Camshaft advice

[thatguy]

OK Guru's,
19' Miller jet, fresh .030 454 BBC.
I built this with a comp 284 extreme hyd. cam. Floated valves and bent an intake. I built it w/ HV oil pump.
10:1 KB pistons
Brodix BB1 280cc runners, 119cc chambers, TR, 2 660's. Am switching to the 750's you guys recommended. AND am going solid. Roller is out of the question, $$$.
This is the cam I am leaning towards, any advice or comments are greatly appreciated!!
Comp. #11-677-4, solid
Gross lift w/ .016 lash = .568 int., .578 Ex.
Dur. @ .015= 274 Int., 280 ex.
Dur. @ .050= 236 Int., 242 ex.
lobe sep. 110
These specs are very close to the Hyd. I have in it, never got it on the water so still don't know how it performes. Am also freshening springs and suspect bad or weak spring led to this on the trailer, even though they were new.
Tommy
Oh, B imp. in a one piece bowl.

[QuickJet]

Isky Z-89 solid flat tappet. Put it in straight up.
Did you aready get rid of the 660's? I had a set on my jet and V-drive and they worked great.

[obnoxious001]

These specs are very close to the Hyd. I have in it, never got it on the water so still don't know how it performes. Am also freshening springs and suspect bad or weak spring led to this on the trailer, even though they were new.
Tommy
So you are saying you revved a freshly rebuilt engine that hard on the trailer with no load?

[thatguy]

I know thats what it sounds like, but it never saw anything over 4K steady for a couple seconds, just to check total advance. (drive coupler not attached) It seemed like it fell off over that right away. I suspect timing events are all wrong, going to break out the degree wheel before I take it apart. it just seemed very strange, maybe the tach is not accurate. I will post what I find. I have built alot of performance engines and have never had one act like this. I have seen comp lifters pump up easily on other occasions, even though I know they are supposed to be the same.
Tommy
Not to wory though, I WILL get it straightned out!!

[bajarunner]

OK Guru's,
19' Miller jet, fresh .030 454 BBC.
I built this with a comp 284 extreme hyd. cam. Floated valves and bent an intake. I built it w/ HV oil pump.
10:1 KB pistons
Brodix BB1 280cc runners, 119cc chambers, TR, 2 660's. Am switching to the 750's you guys recommended. AND am going solid. Roller is out of the question, $$$.
This is the cam I am leaning towards, any advice or comments are greatly appreciated!!
Comp. #11-677-4, solid
Gross lift w/ .016 lash = .568 int., .578 Ex.
Dur. @ .015= 274 Int., 280 ex.
Dur. @ .050= 236 Int., 242 ex.
lobe sep. 110
These specs are very close to the Hyd. I have in it, never got it on the water so still don't know how it performes. Am also freshening springs and suspect bad or weak spring led to this on the trailer, even though they were new.
Tommy
Oh, B imp. in a one piece bowl.
There's more to this than your letting out of the bag, or may be aware of. What was your valve to piston clearance? If it was checked was it checked properly? Or was this just a case of the valve to guide clearance being to tight and the valve seizing in the open position which is normally where it locks up of course. I can't give you cam advise when it sounds like there is more to this, valves don't just hit the pistons and bend even if you over rev the engine and float them a little unless it's a very long duration cam with lots of valve overlap and tight combustion space, you will always have a little room for that oopps moment. Then again maybe the throttle stuck wide open? You had not yet made it to the water so I'm not sure what happened to your engine. Can you ad more info?

[VAMI]

First mock up the head ,usally KB's int valve relief wont clear a 2.250 valve the depth is usally ok but the pocket diameter is to small and the valve will hit ,might have to fly cut those pistons.Brodix is claiming those heads flow to .700.I'd go a little bigger on the cam 240-250 .650 lift

[thatguy]

Heads will be off tomorrow, will know then.

[bajarunner]

After all is fixed I would go with a Engle HL-25/26. It's a solid flat tappet and the specs are as follows. Also I have already build your combo with this cam and a little different cylinder head. The engine also went into a 19' Miller, running a "B" impeller with a Berk pump. I promise you will not be disapointed with this cam.
Engle HL-25/26
Adv Int Duration = 286*
Int duration @ .050 = 242*
Int cam lift = .330"
Int valve lift = .560"
Adv Exh Duration = 292*
Exh duration @ .050 = 252*
Exh lift @ cam = .342"
Exh lift @ valve = .580
Lobe center = 110*

[Warp Speed]

Sounds like the small radial clearance of those pistons is what may have bit you. You'll know soon enough.:(
The Comp 11-604-5 appears to be a good "Shelf" cam for your combo.
I'd install it at 105-106 ICL, and run .020 / .022 lash. Should work real well. A little more rocker arm wouldn't hurt neither!;)
Good Luck

[thatguy]

Well,
Got it apart, no bent valves. 4 cam lobes and lifters wasted. Big time wasted. I have never lost a cam at breakin to my knowledge. I am at a loss. I left inner springs out. used cam lube just like always. I did not use engine oil additive. Got new cam today and will be looking at everything very closely. Will also be going Rotella AND EOA this time.
It seemed like a bent valve because it was building compression on exaust stroke, then releasing it through intake opening. Popping through carb sporatically.
oh well, try again.
Tommy

[Sleeper CP]

Thats a shame.:( I have read a couple of articles about cams going flat on brake in because the new oils we have to buy are lacking in the right properties to lube the cam. Have read any of the same info?
Sleeper CP

[cfm]

Well,
Got it apart, no bent valves. 4 cam lobes and lifters wasted. Big time wasted. I have never lost a cam at breakin to my knowledge. I am at a loss. I left inner springs out. used cam lube just like always. I did not use engine oil additive. Got new cam today and will be looking at everything very closely. Will also be going Rotella AND EOA this time.
Tommy
That will help. Many people now ask for and buy the better P-55 cam core. Comp offers this but salesman might not know. Most other cam companies offer this too - Bullet, Cam Motion, etc,etc
If hydraulic lifter - get the one's with hardened foots. Delco/Delphi 's have this and some other companies offer it. You'll see a different material on the bottom of the lifter.
If solid lifters, the ones with EDM holes seem to work well, if on a good core of course.
To reinforce this - EOS is a must !!!!

[sonny glide]

Run The Roller, Ur worth it!:D

[ck7684]

Are the lifter bores square? Was the oil pump blueprinted? Was the cam for the correct year BBC? Just some thoughts...if it's in your budget, get a roller...

[79centurion]

I have lst one on break in recently. It was before I read about the oil crap:mad: The last two I broke in with rotella and so far so good. Also the cams are as good(either metal or hardening) as they use to be. I would recomend like cfm said and get a better core to start with.
Dan

[396_WAYS_TO_SPIT]

Use valvoline racing oil! It has zinc in it whick helps the cam stay alive. Add 2 bottles of gm's EOS. Add 1qt of oil extra, this will allow the crank to grab more oil and sling it on the cam;)

[sanger rat]

I speed coated the lobes on the last three hydraulic cams I have installed and have had no problems.

[boats&bars]

Well,
Got it apart, no bent valves. 4 cam lobes and lifters wasted. Big time wasted. I have never lost a cam at breakin to my knowledge. I am at a loss. I left inner springs out. used cam lube just like always. I did not use engine oil additive. Got new cam today and will be looking at everything very closely. Will also be going Rotella AND EOA this time.
It seemed like a bent valve because it was building compression on exaust stroke, then releasing it through intake opening. Popping through carb sporatically.
oh well, try again.
Tommy
Run diesel oil Rotella is great stuff lucas wouldint hurt either good luck.....

[thatguy]

Sanger Rat,
What is "speed coating"? I will be firing it again tomorrow. I have Comp. Cams EOA and Rotella. The guy at the local machine shop said he had this problem suddenly a few years ago and started using the comp additive w/ Valvoline racing oil with success. he also said he runs 4 oz. of the same additive on every oil change.
Tommy