Prop question

[BobbyB]

I have a 77 Spectra20, AC 15:1 gears, and 2speed TH400. I'm running a 3 blade Menkens prop; boat gets to about 4100 RPM at top speed. I have gathered that running a 2 blade prop will increase the RPM's and get me a higher top speed. How do I figure what size/pitch to use? What are the disavantages of the two blade? I can only imagine that planing out will take a little longer. Should I try changing up the 3 blade instead?

[boatnam2]

4100 shit my boat idles at that rpm,may want to check prop might have a empty coors light box stuck on it.

[BobbyB]

I thought that was the high performance coating. I'll remove and drop in. Thanks for the tech advice.

[Sangster]

How bout's a little motor info............:confused: :confused: :confused:

[BobbyB]

How bout's a little motor info............:confused: :confused: :confused:
great idea. It's a LS6, MSD ign, Holley dbl pumper, lightning headers. I saw a build sheet that came with it and it states 10:1 compression. The boat is how I bought it.

[Schiada Time]

Bobby B- What size propeller? I would say that with your gears you should be spinning an 11x15 or 11-1/4X15 3-blade. Your boat being a cruiser is better suited for a 3-blade. If you are pulling kids and skiers you will want the 3-blade for all around use but your current prop is not letting you get into an RPM range where your Horsepower is working for you. You need to be spinning that motor between 5000and 5500. A 2-blade will vibrate more. You could take the prop you have and have it shaved down or re-cupped to bring the rpm's up.
Schiada Time

[BobbyB]

Right on ST, I appreciate the reply. I thought there was a few drawbacks. I like the performance now, I just figured that it wasn't getting there RPM wise. My jet ran a bit higher. So to determine what size prop I have, I measure the diameter or is it stamped on the prop somewere? I tried to check it out before, but I didn't know exactly where to look.
Thanks,

[Schiada Time]

Bobby B-Take your prop to a good prop guy and have him spec it out for you. You cannot always trust what is stamped on the prop if it is a used propeller or what came with the boat as people have them cut down or cup pulled out or added depending on what the prop is doing RPM wise with various engine configurations. If your boat has a Turbo 400 it should be a 3-speed transmission. I am going through this prop quest now myself with my '22 Schiada that has a 502 BBC/Turbo 400-1.10 ratio combo and with an 11.5X15 my boat spun 5100 rpm. With what I thought was a 12X15-which is what was stamped on the prop it revved to 5800 rpm. This is a perfect example of not trusting the stamp on the prop as why would a larger diameter prop turn more RPM? My motor is built to revv to 5800 so my prop guy said to get the propeller dialed to allow the motor to revv to around 5600 (you want to be within 200 rpm of your max allotted) so I get the HP out of it without ringing its neck. On this particular propeller there is a cup on the edge of each blade and removing that will provide more RPM. I have a feeling you are running a 12x15 prop now and with your gears the larger diameter and pitch configuration is not allowing your engine to revv up past that 4700. I don't know where you are located but the guys at Wilmington Propeller (Gary and Tom) are working on my prop quest now and can help you out as well. There number is 310-518-1133. Good luck with your prop quest.
Schiada Time

[lilrick]

Biatches!

[BobbyB]

If your boat has a Turbo 400 it should be a 3-speed transmission...................................... .............................. I don't know where you are located but the guys at Wilmington Propeller (Gary and Tom) are working on my prop quest now and can help you out as well. There number is 310-518-1133. Good luck with your prop quest.
Yeah, it's a TH400, but the 1st gear is locked out; although at times it feels like it wants to drop down into it.
I am sittin' on the Car-SON/ Wimas border as we speak. I will figure out what is really goin' down and give them a hollar.
Thanks again for the info, and I'll keep you posted.
Biatches!
Yeah Man:D

[Schiada Time]

Bobby B-That's cool that 1st is locked out. It is so low I almost never use it although it is nice to have when idling up to the trailer. I'm sure you know but never drive that thing on the trailer. Idle it up to the tail end of the trailer, shut her down, and walk her on. When I bought my boat the prop shaft, rudder, and fin were bent and have all been replaced because the morons before drove it on. Good luck with your propeller research. By the way what part of Torrance are you in? I was born and rasied there and moved to Fullerton 2 years ago. My folks live on Prospect and Del Amo. Graduated in '94 from West High.
Travis

[FrznJim]

BobbyB I bought that prop new from Tom Bentley @ Menkins. Check the side of the prop, I think it's a 11-1/2 x16. If you're rpms are down to 4100, I'd check the timing, then compression, then leak down. I'm thinking we always got 4500-4600 when we had the boat. BTW I have a BBC Hyd Roller Camshaft kit in AZ now for that LS6 if you want to get 50 more ponies.

[BobbyB]

Bobby B-That's cool that 1st is locked out. It is so low I almost never use it although it is nice to have when idling up to the trailer. I'm sure you know but never drive that thing on the trailer. Idle it up to the tail end of the trailer, shut her down, and walk her on. When I bought my boat the prop shaft, rudder, and fin were bent and have all been replaced because the morons before drove it on. Good luck with your propeller research. By the way what part of Torrance are you in? I was born and rasied there and moved to Fullerton 2 years ago. My folks live on Prospect and Del Amo. Graduated in '94 from West High.
Travis
Yeah, thankfully I had a buddy take me out and show me the ropes of puttin the V-drive on the trailer before I tore it up. I ended up getting a trailer from SpectraBrent that had a winch (O.G. trialer had floater bar), and a catwalk so it makes it easier.
Well whaddya know, it is a small world. Born and raised as well, and lived there almost my life (aside from short stay out in Glen Avon). I grew up in the L.A. Strip area (Torrance P.O.). I went to Torrance High, graduated in '92 (F.Y.P.;) ). Know a lotta folks from West, though, and still hang out with a few of them. My wife's uncle lives off spenser right across from the Victor elementary. Her cousin went to West; I think she graduated in '92 as well. We live over by south. Just moved in, and we're diggin' it.

[boatnam2]

i say make a couple of anchors out of of them cheby heads,bump the comp up to 12.1 put some real heads on it,get a good cam and your good to go.Big baller from south torrance you need to step up on the horsepower a little and quit messing with the truck motor!

[BobbyB]

BobbyB I bought that prop new from Tom Bentley @ Menkins. Check the side of the prop, I think it's a 11-1/2 x16. If you're rpms are down to 4100, I'd check the timing, then compression, then leak down. I'm thinking we always got 4500-4600 when we had the boat. BTW I have a BBC Hyd Roller Camshaft kit in AZ now for that LS6 if you want to get 50 more ponies.
Now this is why I am glad I bought the boat.....I can always reference the old owner :D Thanks for the info Jim. I was planning on picking your brain a bit, before this was all over. I have it at a friends shop getting serviced. I told him of the RPM's, and the problem was I couldn't remember what they ran at before when I first got it :confused:, but I could swear they ran higher. He seemed to think that a tune would fix the problem. I have yet to run a compression or leakdown test. I will play with the timing to check to see what happens, and go from there. I am always interested in collecting more ponies. PM sent. I will be in Parker for Easter, if you're around, maybe we can hook up.
Thanks,

[BobbyB]

i say make a couple of anchors out of of them cheby heads,bump the comp up to 12.1 put some real heads on it,get a good cam and your good to go.Big baller from south torrance you need to step up on the horsepower a little and quit messing with the truck motor!
Well now, speakin' of BIG BALLERS!, lemme step aside:rolleyes: ..........my daughter calls your boat a "SHIP" cuz it's so stinkin huge :D . Yeah, I know the ole Spectra is small potatoes for you, but you better watch what you say about her else we may have a pralung :mad:. I'm not opposed to bumpin' up the motor, but I would like to keep is as reliable as possible, and able to run off the pump. SUCKA!!!:)

[boatnam2]

ahhhhhhhhh bobbyb i like the old spectra,just would like to see her spin a little rpm.

[BobbyB]

And you know this MAN!!! :D

[BobbyB]

Jim,
I sent you another PM for the parts. Lemme know. I'm in no hurry. If you want, I could go visit your friend Al again and pick them up.
Thanks,

[lilrick]

HAY BOBBY!! I have two 2-blade props you can try.562 307 5578

[BobbyB]

HAY BOBBY!! I have two 2-blade props you can try.562 307 5578
Righteous! I might have to hit you up just to see. Maybe turn it into an outting. I will see what I come up with after the tune and whatnot.

[BobbyB]

after looking things over, we found the intake manifiold was loose, as was some of the bolts on the headers. I can only assume that the vacuum loss was the cause of the problem. I have yet to run it to see the outcome do to interior work being done. Thanks for the suggestions, opened my eyes to other potentials.
Speaking of potentials, we found the steering cable had a couple of bad spots in it, and needs replacement. Got to thinking and thought that if we were fixing it, we might want to look at some upgrading. A double cable system seems to be the way to go; does anybody have any thoughts on this? Is the double cable needed, or should I just stay with the single cable system?
Thanks,

[BobbyB]

I should try posting this in the just jets maybe...... I guess I ain't in the club

[boatnam2]

shutdown by the v-drive boys:D maybe shoot old CBR and see what he thinks!

[LD Mandella]

I you are going to be seeing any speeds above 65 I would definately get a dual system, preferably the calgo, the rack and pinion is OK but the Calgo is better IMHO, I would do the dual steering regardless as steering is kinda important. BTW Rex has all the steering stuff.

[BobbyB]

I was talking about it, and we are going to price out the dual and see what's what. Thank you for the response,I appreciate it.

[BobbyB]

shutdown by the v-drive boys:D maybe shoot old CBR and see what he thinks!
Yeah man, you know us greenhorns don't do nothin' but ask dumb questions. I figure I gotta break it a few more times before I really get to know it better.