SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: bills79southwind on August 30, 2009, 03:48:25 PM
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After some a lot of hours of wrenching, I ultimately found the problem which ended up being a bad lifter and cam lobe being flattened out. Here is the previous thread in case anyone is interested.
I need some help getting a new cam and lifter kit. The heads I have are GM high performance heads. My max RPM's are around 5200 to 5300 max. I'm pulling the cam tomorrow, but I have no clue what the current cam is. Any suggestions would be appreciated. Thanks...
Bill
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As I stated in the other thread, if you can swing it, go hydraulic roller, the headaches you save will be enourmous, there will be HP gains as well.
Because you are going to be under 6k RPM a hydraulic should be the cam of choice (like little hydraulic rev limiters ;D
Comp Cams has always treated me very well, never had an issue with their products.
They actually make marine specific cams to meet your needs, they are marketed under the Xtreme Marine series and I have had much success vs. a custom grind (Read; Clay Smith Cams) never had the opprotunity to use Mr. Horsepower.
If you really have the time and money, go custom and tell the co. exactly what it will be used for. I am sure someone else will pipe in on this, but IMHO non roller would be a mistake.
Sorry for the crappy outcome, but at least you now know what the heck was going on....
GT
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Thanks for the reply GT. Yeah i wasn't happy, but at least I got to the root of the problem. Now you have me freaking out that I could do more damage by not breaking the entire motor down. :banghead: . So if i went with a Hydraulic like you suggest, is there a specific model you would recommend based on my specs or should I just call Comp directly?
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Thanks for the reply GT. Yeah i wasn't happy, but at least I got to the root of the problem. Now you have me freaking out that I could do more damage by not breaking the entire motor down. :banghead: . So if i went with a Hydraulic like you suggest, is there a specific model you would recommend based on my specs or should I just call Comp directly?
Bill.. PM sent.
Plan on tearing the whole thing down to prevent possible further distruction. I recently took one apart for a guy, bearings were all trashed, cylinder walls scored, and steel embedded in the brand new piston skirts. I didn't build the engine originally, and the customer admitted that he made mistakes in break in procedure.
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Thanks for the heads up.. I got your PM and will take your advice.
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Yep I lost a lobe/lifter last season, f'd every bearing in the motor. Piston skirts, cyl. walls. When ever I hear someone say they can't afford a roller cam, I think to myself.....hope you can you afford to build it twice...
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i am building a bbc from scratch now. guess i am going roller, what is the difference?
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i am building a bbc from scratch now. guess i am going roller, what is the difference?
Sent you a PM,, if you call me I can explain some of the questions that you have better. Roller will cost more, especially if you didn't start with one in your Gen 5 block. I have actually never lost a flat tappet cam in all the years I have been building engines, break in is key.
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Im sorry guys but im going to disagree...i mean yes roller cams are the way to go especially for high horsepower motors, but flat tappet cams have been around forever...i think if your building just an above average motor 400-550 ponies you can use flat tappet...dont let em scare you away from them cams they will work just fine...if you wanna flip out the bills for a roller then by all means, but my next motor build will be a flat tappet application and im not affraid...do all the right break in procedures and you will be fine...its your $ do what you please...i think these guys are spending your money sometimes for you!
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I lost mine(cam) after 2 years. I'm not saying there aren't guys out there like Barry that are batting 1000.....I just prefer to look at it like an extra insurance policy. Oil aint what it used to be...
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Oil aint what it used to be...
And That Is The Problem With Non Roller CAms!!!!
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Vr1 designed for flat tappet cams
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Oldsmobiles don't need no stinking roller cams . . . BWAH HA HA HA HA :D
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Vr1 designed for flat tappet cams
That's the off road stuff I run with my roller O0
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I gotta go with Nordie on this. Yeah, roller cams are all the shizzle, I'm an old schooler and am running a solid lifter flat tappet Comp Cam in the Moo. Prolly will stick with that combination on future builds as it works well!
Key is in break in, true, but so is the rest of the engine. My personal viewpoint is everyone skimps on the oil, which is :screwy:
No, You cannot build a performance engine, particularly the way we beat and thrash them in a boat screaming pretty regularly at 5000 + rpm and use off the shelf stuff from Circle K! Use common sense.
I get a lil ribbing about using the Joe Gibbs stuff at a buck and a quarter a case, but you know what? I've got probably 20 or 30 times that , or more, in these engines. Flat tappets need zinc and quite a bit of other stuff missing from most off the shelf stuff. After a few emails and phone calls around, Lake Speed, yeah, that's his REAL name, at Joe Gibbs convinced me to try it. He was right, even though he has never even been on a jet boat in his life. Only problem I have is a poorly installed oil pan (My own fault, :banghead: will be fixed this winter), that leaks a lot of the expensive stuff (About a half a quart a trip on long weekends like Big River).
I guess to make a long story short, which is too late, don't be afraid of flat tappet cams. They are just fine for what we do with proper maintenance.
Ray