Plugs still white!!!

[DUCKY]

I am up to 90's and 94's in my HP950 Holley. Factory jetting in this carb was 78's all the way around. This is on an 8:1 468 Chevy with Team G intake, little oval port heads and 302/544 Crane cam, in my 18' v-drive. Motor is running better, but still has a miss at WOT (46-4700rpm)and the plugs are still white. I added raw fuel to the engine at WOT with my nitrous (fuel) solenoid, and the miss went away, but I also lost rpm, of course. You would think that adding that much fuel to it would make the plugs turn black, right? Wrong! They were a nicely colored greyish tan. That makes no sense, now does it? What do you guys think?

[Hotcrusader76]

Scott,
Check your email.
~Ty

[DUCKY]

I did. Thanks Ty.

[Blown 472]

you changed tha heat range?? it will take some time to color them.
If I remember right I read some where that if you are jetting a bunch over stock then something else is wrong, I think it is on the holley website.
[ January 02, 2003, 05:35 AM: Message edited by: Blown 472 ]

[DUCKY]

I haven't changed the plugs (again...) yet. I am going to try another carb I have first

[Thunderbutt]

Are you sure your secondaries are opening all the way. What plug are you looking at? Maybe there is a vacuum leak around the plug your checking. Check 2 or 3 plugs

[DUCKY]

The HP950 is a mechanical carb and it is opening fully. I can only get to 3 plugs (2, 7, and 8) when the headers are hot, but I have looked at all of them after cool down, They all look about the same. (which is like s**t!!!)

[Maxey]

Hello "Ducky",
I think your problem is either lack of fuel (fuel supply) or ignition. In my opinion, your carburetor is too large for your application. That aside, I would reccomend 80's on the primaries
and 82's on the secondaries. I ran this setup on a 502 BBC with similar modifications in a 18'
DiMarco runnerbottom with No problems and 90's in the mph. I used an MSD ignition, with a
magnetic pulse distributor. Hope this helps.
Maxey

[DUCKY]

You're the second person to say that. I am going to try a modified 750 that my Dad has. Is it because the engine, being the "air pump" that it is, cannot pull sufficient air through the carb for a strong enough booster signal for proper fuel metering?

[Hotcrusader76]

Bingo! Exactly.

[missilemud]

have you tried checking the carb at the base? alot of time a holley wears out if you have to big a return spring,try this , when its running work the shafts on the butterflys and listen for a whistle, had a simular problem, it tuen out to be the base plate was beat .

[Hotcrusader76]

His carb is brand new. Bottom line is...
After I looked over his build last night, after he sent me a spec sheet, I determined that his carb was too big. His motor just doesn't draw the necessary air to pull the fuel. He was installing huge jets, and still nothing. A band aid fix would be to shrink the high speed air bleeds, but then his low end would suck, as if it didn't already.
On top of it all he's running drop-leg boosters which have a better high speed response on fuel draw over Annulars, so he was fighting two battles here.
He's better off with a smaller carb for now, and when he upgrades to more HP then he can recalibrate that HP950 to work his motor.
Good luck Scott!
~Ty

[Blown 472]

Ok, not to start a flame war, but I am not buying the too big carb thang, I have a friend (believe it or not) who has a 340 mopar, flat tappet cam, 11 to 1 ish comp in a car that has a 950 hp on it, no bog, no flat spots, off idle stand on it and it flat huals ass right to 7 grand. So I am confused now.

[Blown 472]

One more thing, I was just taking a duke and pondering, maybe what you are seeing is two fold, first too hot a plug to get a read, secondly high speed miss, too big a jet and you are sucking the bowls dry, way to check for that if you are in tha boat and dialed into it and it lays down, pull tha throttle back let the fuel catch up and then dial back into it, if it comes on strong and lays down agian, no fuel in tha bowls, then agian I ate alot of paint chips as a kid so take it for what it is worth.

[DansBlown73Nordic]

I don't by the carb size thing. I have a good friend with a 283 SB and he runs a 780 cfm Holley. The car runs great. So this 950 should work on a Big Block.
Check the manifold bolts......

[Infomaniac]

Guys there is a lot more to consider than just the size of the engine and size of the carb.
I think the best way to describe "carb too big" is: Does the vacuum signal provided by the engine match the requirements of the carb.
A small engine can give a good enough vacuum signal to run a bigger than normal size carb depending on many differences in the design of the engine and also the combination "build" of the carb.
The reverse also applies. A big engine can give a very poor vacuum signal to the carb and require smaller than normal size carb.
My gut feeling in Ducky's case still is, it is running out of fuel. I had a boat in the past do the same thing. I would raise the float level 2 flats and it would run better. I did this three times and determined that the fuel system was just not providing enough volume.
[ January 03, 2003, 07:23 AM: Message edited by: Infomaniac ]

[Blown 472]

Hey info, since you live close to dorthy and toto, ever seen any twisters?

[Infomaniac]

I have only seen 1
No witches were killed

[Blown 472]

Infomaniac:
I have only seen 1
No witches were killed Up close?? or close enough to hear it? must be some serious stuff.

[DUCKY]

Am I not correct in saying that if I had insufficient fuel volume, then my pressure would also suffer? I have a gauge on it, and it never leaves 7-7.5psi. After a WOT run, I shut it down clean, and pull the bowl screws out, the bowls are full. And I have checked the intake and carb base for vacuum leaks with propane. Guys keep in mind too, I have the little tiny oval port heads. The intake ports are smaller than that of a 350!!!

[Blown 472]

Then you should have a good vacuum signal. What size lines are you running from your tank to the pump??
correct me if I am wrong but pressure is a function of resistance, you can have all pressure you want in a 5/16 line and no volume, or pressure and more volume in a 1/2 line.
[ January 03, 2003, 07:59 AM: Message edited by: Blown 472 ]

[Hotcrusader76]

Blown 472:
Ok, not to start a flame war, but I am not buying the too big carb thang, I have a friend (believe it or not) who has a 340 mopar, flat tappet cam, 11 to 1 ish comp in a car that has a 950 hp on it, no bog, no flat spots, off idle stand on it and it flat huals ass right to 7 grand. So I am confused now. Scotts motor is 8:1 on compression. Big difference there, no?

[Hotcrusader76]

Dans66Stevens:
I don't by the carb size thing. I have a good friend with a 283 SB and he runs a 780 cfm Holley. The car runs great. So this 950 should work on a Big Block.
Check the manifold bolts...... Apples and Oranges here my folks. 780cfm Vacuum secondary? Almost positive it is, which is still big for a 283 but should work considering the secondaries will only open as much as the motor allows. What type of cam and compression is he running also...

[Hotcrusader76]

DUCKY:
Am I not correct in saying that if I had insufficient fuel volume, then my pressure would also suffer? I have a gauge on it, and it never leaves 7-7.5psi. After a WOT run, I shut it down clean, and pull the bowl screws out, the bowls are full. And I have checked the intake and carb base for vacuum leaks with propane. Guys keep in mind too, I have the little tiny oval port heads. The intake ports are smaller than that of a 350!!! Is that free flowing pressure or static?

[78Eliminator]

Ty,
What's the deal with these guys not running their dual setups not squared? I thought it was pretty common to loose the power valves, jet higher and square for a dual setup? You don't loose a whole lot missing your powervalves. We're not talking about daily drivers here where "streetability" comes into play. Anyway, I guess there are many ways to set up a carb, I just thought the simpler, the better.
J

[Hotcrusader76]

To each his own...right J? Don't try to start another Power valve thread again...LOL
058...where are you on this? LMAO

[Blown 472]

Hotcrusader76:
Blown 472:
Ok, not to start a flame war, but I am not buying the too big carb thang, I have a friend (believe it or not) who has a 340 mopar, flat tappet cam, 11 to 1 ish comp in a car that has a 950 hp on it, no bog, no flat spots, off idle stand on it and it flat huals ass right to 7 grand. So I am confused now. Scotts motor is 8:1 on compression. Big difference there, no? Maybe, but the ports are big and so is the cam, he said he has the small port heads which should give good velocity in turn which should give a good vac signal at the carb, perhaps a vacuum gauge is in order??

[Blown 472]

One more thing and the reason I bring up the mopar with the big carb, look at the 340 six pack, cast iron exhaust, mild state of tune and 1400 cfm??? that is the reason he put it on.
And in no way am I bagging on anyone, just playing the "why" game, I get it enough from my kid so I need to play it myself.
[ January 03, 2003, 02:19 PM: Message edited by: Blown 472 ]

[Hotcrusader76]

No sweat there hoss... wink
Team G manifolds (which he states he uses) and the cam profile provided (that is the correct profile right Scott?) I would never choose a carb larger than an 850 version (with a custom calibration alone!)
The carb of choice for his set-up as is would be a 750DP or even an 850 Vacuum Secondary (yes they do exist :D )
It sounds like there is alot of mix-matching of parts going on here. Right carb with the right block but with the wrong cam and wrong heads. Oh well, we are all here to help, not badger one another, so please don't be offended if I came off strong... argue :D :D :D

[058]

Hotcrusader76:
To each his own...right J? Don't try to start another Power valve thread again...LOL
058...where are you on this? LMAO I'm here...just lurking. Not sure I want to get involved in this one after that P/V deal :D and since I don't have much info on his particular carb. But just reading whats here I would drop a heat range or 2 on the plugs first and then go back and recheck everything, Ducky did say when he activated the fuel side of the nitrous the lean pop went away but lost power too. I think the jetting is off for a 950 [90s/94s] considering a 4781 is jetted at 80/80 with p/vs. It would also help to know what kind of fuel he is running, if its pump 92 unleaded then that is a big part of not coloring a plug. Read plugs like its running alcohol. Fuel pressure should be taken as close to the carb inlet as possible. I've seen guys take the f/p reading from the pump and have 7lbs but change it to the carb inlet and it drops to 4lbs. What about f/p regulators? bypass or inline? A Holley inline can restrict volume but still show pressure. How about engine timing [total] not enough and the cyl. temp will run off the scale. Hows that for not wanting to get involved? :D :D

[DUCKY]

Hotcrusader76:
DUCKY:
Am I not correct in saying that if I had insufficient fuel volume, then my pressure would also suffer? I have a gauge on it, and it never leaves 7-7.5psi. After a WOT run, I shut it down clean, and pull the bowl screws out, the bowls are full. And I have checked the intake and carb base for vacuum leaks with propane. Guys keep in mind too, I have the little tiny oval port heads. The intake ports are smaller than that of a 350!!! Is that free flowing pressure or static? I have a 10' 1/8" hose on the fuel rail and a hand held gauge I can look at while runnig WOT.

[Hotcrusader76]

Also take on board what O58 said, with regards to where you take the reading and your F.reg

[DUCKY]

058:
Hotcrusader76:
To each his own...right J? Don't try to start another Power valve thread again...LOL
058...where are you on this? LMAO I'm here...just lurking. Not sure I want to get involved in this one after that P/V deal :D and since I don't have much info on his particular carb. But just reading whats here I would drop a heat range or 2 on the plugs first and then go back and recheck everything, Ducky did say when he activated the fuel side of the nitrous the lean pop went away but lost power too. I think the jetting is off for a 950 [90s/94s] considering a 4781 is jetted at 80/80 with p/vs. It would also help to know what kind of fuel he is running, if its pump 92 unleaded then that is a big part of not coloring a plug. Read plugs like its running alcohol. Fuel pressure should be taken as close to the carb inlet as possible. I've seen guys take the f/p reading from the pump and have 7lbs but change it to the carb inlet and it drops to 4lbs. What about f/p regulators? bypass or inline? A Holley inline can restrict volume but still show pressure. How about engine timing [total] not enough and the cyl. temp will run off the scale. Hows that for not wanting to get involved? :D :D I am running 87 octance pump gas and only 28deg of timing, becuase if I advance it anymore, it doesn't want to crank. I run one of the little Holley inline regulators, without a bypass, and yes it's internal passages are tiny, but I didn't even experience a pressure drop when I hit that solenoid. I am reading pressure about 3" from the carb, too.
OH, BTW, that carb my Dad has is a 600 :( , so I am going to stick it on my truck and "borrow" the mech. sec. 750 Edelbrock (Carter AFB) off of it!!! We shall see. I will keep yall posted.

[DUCKY]

Hotcrusader76:
No sweat there hoss... wink
Team G manifolds (which he states he uses) and the cam profile provided (that is the correct profile right Scott?) I would never choose a carb larger than an 850 version (with a custom calibration alone!)
The carb of choice for his set-up as is would be a 750DP or even an 850 Vacuum Secondary (yes they do exist :D )
It sounds like there is alot of mix-matching of parts going on here. Right carb with the right block but with the wrong cam and wrong heads. Oh well, we are all here to help, not badger one another, so please don't be offended if I came off strong... argue :D :D :D I could not find my cam card, but I got that information off of Crane's website, so I assume it's correct. Yes I have a mix-match cluster f**k of parts, but I know plenty of people who have run the rect. port intake with oval heads, with no problems. I figured having the small heads wouldn't be a problem, since I will be stuffing air down it with turbos soon.
My cam choice was pretty simple, I wanted a healthy sounding lopey idle, in a hyd. cam, with a 2500-6000rpm operating range. That's why I bought this one.
[ January 03, 2003, 05:36 PM: Message edited by: DUCKY ]

[DUCKY]

Blown 472:
One more thing and the reason I bring up the mopar with the big carb, look at the 340 six pack, cast iron exhaust, mild state of tune and 1400 cfm??? that is the reason he put it on.
And in no way am I bagging on anyone, just playing the "why" game, I get it enough from my kid so I need to play it myself. Both outer carbs on those "six-pack" systems are vacuum operated. Only the center one is connected to the linkage. And you call a 340 six-pack a mild state of tune? Those things had 10 or 11:1 compression and a nasty solid lifter cam right from the factory!

[Hotcrusader76]

I've run a rect.port with large ovals without a problem to, even though I have recently changed it out... :D
What's the part number on that cam?

[Hotcrusader76]

DUCKY:
Blown 472:
One more thing and the reason I bring up the mopar with the big carb, look at the 340 six pack, cast iron exhaust, mild state of tune and 1400 cfm??? that is the reason he put it on.
And in no way am I bagging on anyone, just playing the "why" game, I get it enough from my kid so I need to play it myself. Both outer carbs on those "six-pack" systems are vacuum operated. Only the center one is connected to the linkage. And you call a 340 six-pack a mild state of tune? Those things had 10 or 11:1 compression and a nasty solid lifter cam right from the factory! No kidding? :D Good catch Ducky!

[058]

28deg of advance and on 87 octane? Its no wonder its shooting ducks. A true 8 to 1 engine should be able to handle 34-36 deg total timing on 87 but you say it won't crank, why? Are you running a locked dist? If you are you should run an advance dist. with app. 12-16 initial and 34-36 total full in @ 3000-3200. Unleaded gas will not color a plug like racing gas will. You should read your plugs like you would an alcohol plug by looking for the heat tracks on the plug body and by the ground electrode. NGK plugs are great for heat reading. Try for 2 to 3 threads on the plug body for a start. One last ??? are you running oval port heads or the "peanut" port heads?

[SUI-CY-COLE]

if its as bad as you say ducky,,check in to a fuel delivery problem....buy a fuel gauge and mount it where you can see it when this problem happens,,and mount it as close to the carb as possible.....just a thought??

[SUI-CY-COLE]

if its as bad as you say ducky,,check in to a fuel delivery problem....buy a fuel gauge and mount it where you can see it when this problem happens,,and mount it as close to the carb as possible.....just a thought??

[Hotcrusader76]

058:
28deg of advance and on 87 octane? Its no wonder its shooting ducks. A true 8 to 1 engine should be able to handle 34-36 deg total timing on 87 but you say it won't crank, why? Are you running a locked dist? If you are you should run an advance dist. with app. 12-16 initial and 34-36 total full in @ 3000-3200. Unleaded gas will not color a plug like racing gas will. You should read your plugs like you would an alcohol plug by looking for the heat tracks on the plug body and by the ground electrode. NGK plugs are great for heat reading. Try for 2 to 3 threads on the plug body for a start. One last ??? are you running oval port heads or the "peanut" port heads? Yes, he's running the small oval ports.

[058]

IMO trying to run peanut port heads is a complete waste of time. Like trying to suck thick milkshake thru a bent straw. These ports are too small to support anything over about 4000 rpm. Were't they originally designed for the 366" truck engine? Get a decent set of heads on that thing and I would bet money your problems go away.

[ACCEPTENCE]

As I read along the thought of fuel pressure -vs- volume keeps coming up. Plumbing, line size, line distance and type of fittings...
Pressure is good but volume counts on top end.
Just a thought.

[GofastRacer]

Personally, I think he's still running out of gas??.... :confused:

[Blown 472]

I had another idea, maybe you could get someone to ride in the back of the boat and look down the carb as you are driving it, if the boosters stop flowing fuel then you have an idea what is going on with it.
The 340 six pack might have some of that stuff but still has stock manifolds that dont flow for chit.

[DUCKY]

SUI-CY-COLE:
if its as bad as you say ducky,,check in to a fuel delivery problem....buy a fuel gauge and mount it where you can see it when this problem happens,,and mount it as close to the carb as possible.....just a thought?? Been there, done that!

[DUCKY]

058:
IMO trying to run peanut port heads is a complete waste of time. Like trying to suck thick milkshake thru a bent straw. These ports are too small to support anything over about 4000 rpm. Were't they originally designed for the 366" truck engine? Get a decent set of heads on that thing and I would bet money your problems go away. The "peanut ports" were on most 454's in trucks through the mid 70's to early 80's. They have 2.08 intake valves and 1.88 exhaust valves (bigger than a fuelie small block). If the good oval ports are good for 6500, and the rect. ports are good for 7500++, then these should get me to 5500...

[DUCKY]

ACCEPTENCE:
As I read along the thought of fuel pressure -vs- volume keeps coming up. Plumbing, line size, line distance and type of fittings...
Pressure is good but volume counts on top end.
Just a thought. 3/8" lines from tanks, to valve, to pump, to filter, and to the carb.

[DUCKY]

058:
28deg of advance and on 87 octane? Its no wonder its shooting ducks. A true 8 to 1 engine should be able to handle 34-36 deg total timing on 87 but you say it won't crank, why? Are you running a locked dist? If you are you should run an advance dist. with app. 12-16 initial and 34-36 total full in @ 3000-3200. Unleaded gas will not color a plug like racing gas will. You should read your plugs like you would an alcohol plug by looking for the heat tracks on the plug body and by the ground electrode. NGK plugs are great for heat reading. Try for 2 to 3 threads on the plug body for a start. One last ??? are you running oval port heads or the "peanut" port heads? My distributor is a GM HEI, which would normally rely on "ported" or "timed" vacuum from the carb to attain full advance. The Holley has no vacuum fittings at all, so I advanced the timing until it cranked hard, then backed it off. This ended up as 16deg static, plus 12 centrifugal equals 28 total. I am installing a 750 mech. sec. Edelbrock carb as we speak that has timed vacuum. My plug(s) electrode changes from brown to black about 1/32" above the bend. The threads have no color.

[DUCKY]

riodog:
or one with a 12" mouth (like my X-wife OUCH!!! jawdrop

[Oldsquirt]

Ducky, at WOT your vacuum advance will not be operating and thus will not add to total timing. If you are going to run the HEI, remove the vacuum advance.I think a couple companies make a "vacuum advance eliminator rod" that will hold the advance plate stationary. At the same time you should recurve the distributor to allow more centrifugal(mechanical) advance. This will allow you to have proper total timing and an initial setting that still allows satisfactory cranking.

[DUCKY]

I always thought ported, or timed vacuum, comes from inside the venturi, and it increases with the opening of the throttle, whereas the opposite, manifold vacuum, drops with the opening of the throttle. Is this not correct? :confused:

[058]

Ducky, We are just trying to help here but trying to diagnose problems from words on a computer screen leaves alot to be desired. The suggestions I tossed out were just some things I thought of by what was posted prior to me reading the last post. It seems the more we get into your combo the more things I see are wrong with it. I stand by what I posted as I'm sure others do too. I say this because everything we have posted you have a rebuttle to. Sorry, but I don't think I can help you anymore. Good luck with your dilemma. :confused:

[Oldsquirt]

Ported(timed) vacuum comes from just above the closed throttle blade. So at idle it will be zero, but as soon as you crack the throttle and expose the port to vacuum it will rise to a value equal to manifold vacuum. At WOT under load, both manifold and ported vacuum will be at a minimum, most likely at or near zero.
Venturi vacuum is vacuum sourced at the carb venturi. It will increase with air flow through the carb. Signal is weak when compared to the other two. The only use I can recall for venturi vacuum was Chrysler using it to trigger its EGR systems.
Vacuum advance units are intended to aid fuel economy while cruising at light load, part throttle operation. Example:cruising down the freeway. In a boat you never really encounter these conditions because you always have a signifigant load on the engine

[Infomaniac]

Increase your total timing 4 or 6 degrees to get the timing burn to the center of the bend of the ground strap on the sparkplug.
See if you can remove the inline regulator. Those things suck. how much pressure will you have if you remove it?
Also you cannot read the plugs after cruising and idling back in.
[ January 04, 2003, 09:10 PM: Message edited by: Infomaniac ]

[Sandbar Junkies]

There's a carb shop in Whittier CA.called C&J engineering.562 946-1388 ask for John he is a genius;he's kinda grumpy so be patient but he knows Holly's better then Holly........

[DUCKY]

Infomaniac:
Increase your total timing 4 or 6 degrees to get the timing burn to the center of the bend of the ground strap on the sparkplug.
See if you can remove the inline regulator. Those things suck. how much pressure will you have if you remove it?
Also you cannot read the plugs after cruising and idling back in. Info, which way does advancing/retarding move the "burn line"? And the regulator is already gone, as is the Holley carb! I put on a 750 mech. sec. Edelbrock. I think I will get to try it tomorrow. I don't forsee a problem without the regulator, as I was more or less using it as a junction block anyway.

[DUCKY]

058:
It seems the more we get into your combo the more things I see are wrong with it. 058,
What do you see wrong with the combo, other than a low compression motor with a big intake and cam?
Keep in mind, I am not leaving it natually aspirated forever... :confused:

[Infomaniac]

The ideal place for the timing burn line is in the center of the bend.

[058]

DUCKY:
058:
It seems the more we get into your combo the more things I see are wrong with it. 058,
What do you see wrong with the combo, other than a low compression motor with a big intake and cam?
Keep in mind, I am not leaving it natually aspirated forever... :confused: There is nothing wrong with a low comp. engine, thats not what I'm talking about. Its the peanut port heads, the timing, the advance [vacume?] The Holley inline fuel pressure regulator. The 28 deg total timing will increase cyl temp, should be 34-36 deg and if you have a starting problem then thats a seperate issue to deal with but don't take it off the total just to get it to start. The Holley f/p reg is designed to run with a small cfm carb if run as a single reg. set-up. Its recommended to run two regs. on a large cfm carb because of the small orface [.090"] in the unmodified reg. As to the Peanut port heads they are designed to run on low rpm engines [truck] and will probibally reach max flow at about 4000 rpm since thats what the truck engines were governed at. The low rpm port velocity was most important to getting a loaded truck moving. And as to you trying to use these heads on a turbocharged application will only hurt the performance of your engine as the boost pressure will not effectively reach the cylinders. You may have high manifold pressure but it won't be getting to the cyls. because of the port restriction. I would much rather have 10lbs of boost that gets in the cylinders than have 20lbs of boost in the manifold but restricted by the head and/or the valve. Don't forget, for every lb of boost will raise charge temp 7 deg. not including any other factors. 10lbs/boost=70degF, 20lbs/boost=140degF. Sorry if I got a little short with you but you seem to refute and question most of the people that are trying to help you. You posted the problem, we're just trying to help by what we see wrong with your combo. wink

[DUCKY]

I just question alot to make sure I fully understand what is being said. I don't want to go off "half cocked" If it seems that I am being argumentative, I'm sorry, I didn't mean it that way. Thanks all of you for your help. I will start saving for some good heads (HEHE)

[MsHotCrusader]

Sorry....wrong log in.....LOL...
[ January 05, 2003, 12:47 PM: Message edited by: MsHotCrusader ]

[Hotcrusader76]

Scott,
I am as well as everone here are with ya!
That's what so great about ***boat, we can all share bias as well as objective opinions on whether something works or not.
Even though our egos :D sometimes cloud the issue, and 058 thinks he's the "PV" king :D , we all share something in common, getting the most out of what he already have.
So what's the update on your progress? Did you get that smaller carb installed? Fuel pressure? Clean fuel filter? Proper engine timing? Air-Fuel-Spark...
~Ty

[058]

Hotcrusader76:
Scott,
I am as well as everone here are with ya!
That's what so great about ***boat, we can all share bias as well as objective opinions on whether something works or not.
Even though our egos :D sometimes cloud the issue, and 058 thinks he's the "PV" king :D , we all share something in common, getting the most out of what he already have.
So what's the update on your progress? Did you get that smaller carb installed? Fuel pressure? Clean fuel filter? Proper engine timing? Air-Fuel-Spark...
~Ty Hey, I didn't say anything about power valves in this thread, it was tough and it took alot of restraint but my good judgement prevailed and not a word was said about...... That would look good on the dash of my Hondo "The Power Valve King Of the WORLD" Waddya'all think?? :D :D :D

[DUCKY]

Hotcrusader76:
Scott,
I am as well as everone here are with ya!
That's what so great about ***boat, we can all share bias as well as objective opinions on whether something works or not.
Even though our egos :D sometimes cloud the issue, and 058 thinks he's the "PV" king :D , we all share something in common, getting the most out of what he already have.
So what's the update on your progress? Did you get that smaller carb installed? Fuel pressure? Clean fuel filter? Proper engine timing? Air-Fuel-Spark...
~Ty It's all done and ready to hit the water, but I haven't had a chance to try it out yet.
And 058, I am not even going to start on power valves, as you are the king! :D :D :D

[GofastRacer]

"Hey, I didn't say anything about power valves in this thread, it was tough and it took alot of restraint but my good judgement prevailed and not a word was said about...... That would look good on the dash of my Hondo "The Power Valve King Of the WORLD" Waddya'all think??"
________________________________________________
Man what fortitude!!, I bow to thee!!!.. http://www.handykult.de/plaudersmilies.de/jump.gif

[supersoaker509]

I am running a ford 466 with that carb and I had the same problem it turned out to be two big of jets it was washing the plugs clean. Went with 74 and 76 problem gone. Carb is a little too big.
Just my 02.
boxed

[DUCKY]

Well I tried the 750, and it ran like SHIT!!!!!
Less responsive at all rpms, and missed worse than it did before. Guess I am going back to the 950 with factory jetting, then I will try a different distributor so as to eliminate the possibility of the HEI crapping out.

[Hotcrusader76]

That 750 was junk then. That carb should have ran alot better, from a throttle response point of veiw.
Sounds like you have some spark problems Scott. Don't touch your carb, dig deeper into that ignition.

[DUCKY]

Guess I will try ignition first :D
But that 750 has less than 5000 miles on it in my Blazer (on a stock 305...) I got it from a friend who ran it one time on his boat, he bought it new.
The thing ran great in my truck, it was just a little oversized, and too rich.
[ January 07, 2003, 04:59 PM: Message edited by: DUCKY ]

[Infomaniac]

One change at a time dude.
Put the 950 carb on maybe a bit richer on the secondaries. Minus the regulator. If it still runs bad then try ignition changes.
[ January 07, 2003, 09:12 PM: Message edited by: Infomaniac ]

[DUCKY]

Here we are again! I don't even care about the plugs at this point, I just want the miss gone!!
I have eliminated the ignition as an issue. Changed to a single point dist. with good coil, set the timing to 34 deg at 3000 rpm, ran it today with the dwell meter attached, no loss of dwell. I also left my timing light attached, and moved it amongst all eight wires and ran it WOT while looking at the light, no miss. I am starting to beleive 058's idea about the heads reaching max flow. Anyone got any heads?
RE-cap, 7psi fuel press, no regulator, tried both my 950 Holley and a 750 Edelbrock, Changed ignition system. What else is left?
Oh yeah, and I nailed it WOT from an idle today, no BS, no bog, it just went to 4600 rpm immediately and started it's usual crap.
[ January 12, 2003, 08:11 PM: Message edited by: DUCKY ]

[502procharger]

i have a carb, intake, and heads from a 500hp. i do not know if any of them would be any help to you, but let me know if trying any of them would be a help.

[Infomaniac]

Ducky, I am sure better heads would help with power but no matter how bad the combination of engine parts it should run clean (no miss) Miss is a tune up issue.
Sorry you are having this much trouble. has the engine ever run clean?

[502procharger]

Ducky, i agree with infomaniac if it were the heads it would not run to it's potential in hp or torque but it should still run smooth. I know it sounds stupid, but i put a new set of plugs, wires, cap and rotor on my motor. Ran ok then started to break down top end. I went through all the same shit you did. carbs, fuel pump, new ignition module, new coil, re-ground motor, tach, wires, just got worse and worse to the point it would start and run smooth, timing was perfect, as soon as i got over like 3000rpm's it spit sputtered and ran like shit. I replaced it with another carb, and some other shit. Finally just for shuts and giggles i re-replaced the plugs and cap and rotor. Holly shit. It ran perfect. I feel your pain, it took like 4 weeks to figure out i needed new pugs again, make sure they are gapped right also. Good luck.

[058]

Correct me if I'm wrong but the way I see it Ducky is using heads that are so restrictive that it is disturbing the fuel mixture, such as lack of velocity in the manifold plenum causing the fuel to "drop out" creating a lean condition in the cyls. He claims to have checked everything else from ignition to plug heat range to fuel del. and various jetting and the problem still exists, where would you guys go from here? :confused:

[BobS]

This is the kind of thing that made me bald (tore all my hair out.) Just like you are describing, low end was okay, started breaking down at the top end. The more it ran, the worse it got. I went through the whole fuel system once and the ignition thing twice. I finally came back to the fuel system. When I replaced the fuel filter for the second time, ta da!, it ran perfectly.

[GofastRacer]

I also got to agree with Info on this, no matter how bad the combination, it should still run, it may not pull the rpm's but it should run, when my bypass stuck open, the motor ran up to 6100 instead of 7500 but the motor never missed a beat!..058 has a good point also but I would say that it would just not make the power!..
I think it's time to start at the beginning again, something has been overlooked?..I would start with the ignition, Why don't you see if you can borrow a Vertex mag along with the wires that you know is GOOD, with a fresh set of plugs, that should clear up any doughts about the ignition!, if it still runs like shit, then it's time to look elsewhere!!...What you guys think?, am I way off here??...... :confused:

[DUCKY]

Alright, I just talked to my brother. The last motor these heads were on was another 468 in his old DiMarco Runner bottom, and it turned 6100rpm, with a rectangular port tunnel ram and two 650 Holleys. I am now wondering about valve float, any ideas? Those springs are pretty weak (20 yr old stockers), but my cam isn't that big at .544 lift. I swear it sounds like theres a rev-limiter on the thing!

[DUCKY]

Infomaniac:
Ducky, I am sure better heads would help with power but no matter how bad the combination of engine parts it should run clean (no miss) Miss is a tune up issue.
Sorry you are having this much trouble. has the engine ever run clean? This motor was in my Dad's Rex-craft, with different heads/valvetrain, and it ran fine. He had BIG ported rect. port heads and tunnel ram with two 750's and a pretty big roller cam. It only turned 5000 rpm due to gears (35% over!) but it ran smooth.

[GofastRacer]

DUCKY:
Alright, I just talked to my brother. The last motor these heads were on was another 468 in his old DiMarco Runner bottom, and it turned 6100rpm, with a rectangular port tunnel ram and two 650 Holleys. I am now wondering about valve float, any ideas? Those springs are pretty weak (20 yr old stockers), but my cam isn't that big at .544 lift. I swear it sounds like theres a rev-limiter on the thing! If those springs are that old, it's time for new ones, even if your cam is mild, they are fatigued, especially if you let the motor sit for long periods of time without backing off the rockers, leaving springs compressed will weaken them quick!. This could very well be your problem!!.. eek!

[DUCKY]

Those heads sat in the garage for 3 years, but they weren't on a motor (Rockers) I think I need springs even if thats not the issue.

[058]

Ducky, What does your dad and brother say about your problems? It seems they have enough experence between them that they should be able to solve your problems and get your engine dialed in. Now you say your valve springs are old wore out stockers, why wasn't that mention early on when this thread started? Why wasn't alot of things mention early on? This thread is now up to about 80-85 posts and you're no closer to getting the engine to run than when you started. I have offered you everything I can come up with as well as the many others who posted. Is this a test? Did we pass? This is worse than studying for a urine test. :confused:

[jstwkd]

Hey ducky
I ran into the same problem with my boat.My comp. is 9.3.I also was using a 950 hp. The motor is a 502.I chased everything under the sun and finally switched from -6 with the real cool looking blue anodized inline filter to -8 line and a huge inline fuel filter from fram.No more pinging.I didnt think I could possably be using that much fuel.I was only spinning 5100 RPM. I was also changing my press at the carb. Went as high as 9.5 psi no change.
This prob. also cost me two motor rebiulds.

[SUI-CY-COLE]

058 anyluck finding that stud girdle nut?

[DUCKY]

058:
Ducky, What does your dad and brother say about your problems? It seems they have enough experence between them that they should be able to solve your problems and get your engine dialed in. Now you say your valve springs are old wore out stockers, why wasn't that mention early on when this thread started? Why wasn't alot of things mention early on? This thread is now up to about 80-85 posts and you're no closer to getting the engine to run than when you started. I have offered you everything I can come up with as well as the many others who posted. Is this a test? Did we pass? This is worse than studying for a urine test. :confused: I never figured valve float could even be an issue at such a low rpm, so I didn't think it was relevant. Still not sure it is, it's just something else to try. My Dad is pretty knowledgeable, but this one is out of his realm, and my Brother doesn't chase problems well either. I was just sharing their experiences with the same parts. And if you have to study for a pee test, I'm Sorry :D

[058]

SUI-CY-COLE:
058 anyluck finding that stud girdle nut? Sui-cy, JBG hooked me up with a couple from his parts bin....we be in business now. :D

[058]

Ducky, What are the chances you can borrow a set of good heads, igintion and whatever else that may be in question to try just to see if you can get that boat to run the way it should? idea

[502procharger]

Yah well my dad is cooler than your dad :p wink :D J/K
This sucks so bad. i feel for you. i went through very a very simmilar thing and it drove me insane. i could not sleep at night b/c i was thinking about it non stop. I feel your pain bro, stick with it and you will figure it out.

[sterling]

While reading through all of the above posts, one thing caught my att. Having dealt with GM HEI for a long time , altough not any more, and after reading hundreds mabe thousands of plugs my advice for you is as follows... #1 like was said before it is nearly impossibe to read plugs using pump gas. #2 HEI systems require 13.7vdc - 14.6vdc to operate, also and most important is that it receives enough current. Make sure its at least 12ga or even better 10ga. from batt. + through any switches to the dist(no butt connectors). I've had high speed skips on several different occasions in different applications caused by #2. And after all its very easy to check and re-string if needed. Just my .02

[Badboat1]

I ,Have to go with the ignition problem issue as Sterling stated.The valve springs would have to be pretty junk to do it at such a low RPM.But as you stated they have set up for along time and were used to start with.
Badboat1

[DUCKY]

Badboat1:
I ,Have to go with the ignition problem issue as Sterling stated.The valve springs would have to be pretty junk to do it at such a low RPM.But as you stated they have set up for along time and were used to start with.
Badboat1 I pulled a couple of springs and had them checked. How about 53# on the seat!!! jawdrop
Ouch!!! They are toast! I will replace them b4 I run it again. I hop thats it. My cam card specifies 130# on the seat at 1.880" installed height and 300# at 1.336"

[058]

My ball-point pens have more pressure that that. :D :D :D

[GofastRacer]

I would say, problem solved!.. eek! :D

[Infomaniac]

New springs for sure.
I would think maybe your valves were hitting the pistons depending on your clearances. You might get lucky only having about 544 lift. You need to check for bent valves.
Leak down should tell you that. They do not seal well when even slightly bent.
[ January 17, 2003, 10:29 AM: Message edited by: Infomaniac ]

[78Eliminator]

Ducky, are you SURE you are not starving the engine of fuel!!??

[Infomaniac]

78Eliminator:
Ducky, are you SURE you are not starving the engine of fuel!!?? Good one Justin.
In a way he was.

[Blown 472]

DUCKY:
Badboat1:
I ,Have to go with the ignition problem issue as Sterling stated.The valve springs would have to be pretty junk to do it at such a low RPM.But as you stated they have set up for along time and were used to start with.
Badboat1 I pulled a couple of springs and had them checked. How about 53# on the seat!!! jawdrop
Ouch!!! They are toast! I will replace them b4 I run it again. I hop thats it. My cam card specifies 130# on the seat at 1.880" installed height and 300# at 1.336" Well at least the cam is broke in now. :D

[78Eliminator]

Infomaniac:
78Eliminator:
Ducky, are you SURE you are not starving the engine of fuel!!?? Good one Justin.
In a way he was. Well, it just seems like he is bouncing off a rev limiter. This can be caused by cutting off the spark, fuel or timing (the three main factors). I wonder if he is running those crappy filters in the carb fuel bowls? Take those suckers out if you are. Replace and/or clean your primary fuel filter(s). Remember, just becuase you are getting 7-9 psi at your fuel pres guage, it doesn't mean you're getting it to the needle/seat valves....

[Infomaniac]

Justin,
I thought you were being funny. I guess you have not read all the posts.
I thought he was running out of gas along with a few others. It was actually his valve springs.
You posted that he is probably running out of gas right after he posted the real problem.
It was the perfect opportunity to be a smart ass and I thought you beat me to it. :D

[78Eliminator]

Infomaniac:
Justin,
I thought you were being funny. I guess you have not read all the posts.
I thought he was running out of gas along with a few others. It was actually his valve springs.
You posted that he is probably running out of gas right after he posted the real problem.
It was the perfect opportunity to be a smart ass and I thought you beat me to it. :D Uhhhhhh, yeah! That's what I was doing, Info...NOT. I should have read before I posted. I am a smart ass, but I was more like a dumb ass on this one.

[Badboat1]

I think 53 # on the seat would work on my lawnmower.And as Info informed you check for any bent valves. I bet you will have a good running boat now.
http://free.***boat.net/ubb/Avatars/Forum_Graphic_Depot/Texoma_0008.JPG
Badboat1

[Hotcrusader76]

WOW!!! That's quite a large pump you have there eek!

[Infomaniac]

Yea that thing runs big also.

[stix818]

Well any luck DUCKY. If so it seems like this was a pretty good learning experience (a costly one too). Hope everything is running better. I remember tearing apart my CRX and it had 75 #s on the seat and I couldn't believe it. I've never seen anything that low before until now.

[DUCKY]

Well, I am working on it now. I don't see nay damage to the locks/retainers, no bent pushrods etc...
The shop I had "test" the springs (Varner performance here in Havasu) was a joke! I don't even think they tested them! And they left out one valve stem seal.
I took the springs off myself and took them to a reputable machine shop (JD Machine). Yes, they were 53# on the seat, and less than 200# open because they were installed at 2.180" The heads were machined for rotators (.250" thick), and they have been removed. My springs are very heavy, in fact they are a little too heavy for my cam. At 1.880 (proper installed height for BBC), they were over 150# and nearly 400# @1.336" We shimmed them for 110# on the seat and 305# open, and ended up with 1.910 installed height. I will run it tomorrow and see if it did any good.

[Badboat1]

Thanks,Info damn Suck and Blows are a hard thing to make run hard.Just got a chance to post 5 more jobs coming and a resto on a jet also.Damn got to say take my real job and shove it.Been at at it all last nite and today and back at it in the morn.
Badboat1

[stix818]

DUCKY if you need any assistance let me know. My old man's speed shop is in Mohave Valley and he's the one you want if you want it done right!!!

[Infomaniac]

DUCKY:
Well, I am working on it now. I don't see nay damage to the locks/retainers, no bent pushrods etc...
The shop I had "test" the springs (Varner performance here in Havasu) was a joke! I don't even think they tested them! And they left out one valve stem seal.
I took the springs off myself and took them to a reputable machine shop (JD Machine). Yes, they were 53# on the seat, and less than 200# open because they were installed at 2.180" The heads were machined for rotators (.250" thick), and they have been removed. My springs are very heavy, in fact they are a little too heavy for my cam. At 1.880 (proper installed height for BBC), they were over 150# and nearly 400# @1.336" We shimmed them for 110# on the seat and 305# open, and ended up with 1.910 installed height. I will run it tomorrow and see if it did any good. If anyone is not completely certain what all that means, here are some explainations.
Valve Spring Set Up On Havasu Barney Site. (http://www.havasubarney.com/cgi-bin/ikonboard.pl?s=3e2ad3f90960ffff;act=ST;f=25;t=30)

[DUCKY]

It's fixed!!!! Pulls like a raped ape to 5300 now and sounds sweet!!! I do need to recurve my distributor, but thats about it, then it's nitrous, turbos, and taller gears time!!
Thanks!

[Infomaniac]

:D :D :D :D :D

[GofastRacer]

DUCKY:
It's fixed!!!! Pulls like a raped ape to 5300 now and sounds sweet!!! I do need to recurve my distributor, but thats about it, then it's nitrous, turbos, and taller gears time!!
Thanks! Right on!!.. wink :D :D :D

[Fiat48]

I got lost with all the changes and the trying to fix. So the culprit was the valve springs?
Wonder what the adding fuel in the first post had to do with making the miss go away?
Maybe I'm missing something. I'll read again.
Nice pictures Infomaniac on setting up valve springs. Least the spring checker made me feel better about my homemade one!
[ January 19, 2003, 10:01 PM: Message edited by: Fiat48 ]

[78Eliminator]

DUCKY:
It's fixed!!!! Pulls like a raped ape to 5300 now and sounds sweet!!! I do need to recurve my distributor, but thats about it, then it's nitrous, turbos, and taller gears time!!
Thanks! Now we just need to get you some more revs. I have a 468 that does 6 grand.......

[GofastRacer]

I have one that does 7500!.. wink

[Infomaniac]

GofastRacer:
I have one that does 7500!.. wink Better check those spring tensions !!!

[DUCKY]

I am pulling a 17" prop and 22% gears. Once I make the slippage go away, and add the bottle, I will be at 6000 and probably running in the 90's. That's fast enough. And Fiat, I think adding the fuel caused a drop in RPM, which made the miss disappear.

[GofastRacer]

Infomaniac:
GofastRacer:
I have one that does 7500!.. wink Better check those spring tensions !!! Just put a new set on!.. wink
Thanks for the reminder!!.. :D

[058]

Fiat48:
I got lost with all the changes and the trying to fix. So the culprit was the valve springs?
Wonder what the adding fuel in the first post had to do with making the miss go away?
Maybe I'm missing something. I'll read again.
Nice pictures Infomaniac on setting up valve springs. Least the spring checker made me feel better about my homemade one! You weren't the only one who got lost. This thread read like an Agatha Christy mystery novel. :confused:

[Hotcrusader76]

So what's the news? Is she being splayed out across the garage yet? Please update..
[ January 20, 2003, 10:57 AM: Message edited by: Hotcrusader76 ]