SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: el mojado on September 04, 2017, 06:44:58 PM
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I am running a roller solid cam. Do I need to run a bronze gear?
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I am running a roller solid cam. Do I need to run a bronze gear?
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In most cases yes.... What Cam? Solid rollers are typically billet and you can you a bronze gear or a melonized steel gear...
I prefer the bronze because they are easy to replace and inspect.
Unless your cam has the iron gear on it.... (rare).
GT
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I was told it was a solid Howard's cam. I'm taking it out now to check the grind number. No cam card was given to me when I bought the engine.
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So here it is. Now I gotta find out the specs. Does this look like it needs a bronze gear? How can I Tell?
121633-08
13431
2002 B
Howard's cam. Anyone familiar with this cam? It's in a 496. Gonna run the aluminum center rise Mercruiser manifolds, air gap, and 950 holley set up by performance carb in Ontario. 20.5 70s day cruiser. Jacuzzi WJ, stainless impeller marked "A".
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SKU:121633-08Stock #:121633-08UPC #:840793106325
Camshaft Type: Mechanical RollerDuration Exhaust: 295Duration Intake: 289Duration at 050 Exhaust: 263Duration at 050 Intake: 257Engine: 396-502 (Mark IV)Firing Order: 1-8-4-3-6-5-7-2Intake Centerline: 104Lobe Separation: 108Engine Manufacturer: ChevroletRPM Range: 3400 to 7300Valve Lift Exhaust: .725
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From Howards cams website. Opinions? Thoughts? Remember.... this came installed already.
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Bronze or composite gear... JMHO
Check this out.
http://www.onedirt.com/news/its-all-in-the-twist-taking-the-confusion-out-of-distributor-gear-compatibility/ (http://www.onedirt.com/news/its-all-in-the-twist-taking-the-confusion-out-of-distributor-gear-compatibility/)
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108 Deg. lobe separation sounds kind of tight for a jet boat motor. U might run into reversion issues? If you are not running headers I may be off on that.
SKU:121633-08Stock #:121633-08UPC #:840793106325
Camshaft Type: Mechanical RollerDuration Exhaust: 295Duration Intake: 289Duration at 050 Exhaust: 263Duration at 050 Intake: 257Engine: 396-502 (Mark IV)Firing Order: 1-8-4-3-6-5-7-2Intake Centerline: 104Lobe Separation: 108Engine Manufacturer: ChevroletRPM Range: 3400 to 7300Valve Lift Exhaust: .725
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I hope you marked each lifter where they came from. Important if you put that cam back in the same lifter go in same lobe.
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Agree with GT on gear
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I hope you marked each lifter where they came from. Important if you put that cam back in the same lifter go in same lobe.
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Roller cam and lifters dont care so much.
Dan'l
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SKU:121633-08Stock #:121633-08UPC #:840793106325
Camshaft Type: Mechanical RollerDuration Exhaust: 295Duration Intake: 289Duration at 050 Exhaust: 263Duration at 050 Intake: 257Engine: 396-502 (Mark IV)Firing Order: 1-8-4-3-6-5-7-2Intake Centerline: 104Lobe Separation: 108Engine Manufacturer: ChevroletRPM Range: 3400 to 7300Valve Lift Exhaust: .725
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263* @ .050" on the Exhaust won't be happy with center rise manifolds. (Read : Reversion :( )
Nearly 3/4" lift is going to be hard on all the valve train. (More wrenching than boating?)
It's in a 496. Gonna run the aluminum center rise Mercruiser manifolds, air gap, and 950 holley set up by
performance carb in Ontario. 20.5 70s day cruiser. Jacuzzi WJ, stainless impeller marked "A".
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(Heavy Ass) 1970's DAY CRUISER., Enough said.
Cam It Mild.
Something like this: https://www.summitracing.com/parts/hrs-120183-10/overview/make/chevrolet
Drive it forever.
Dan'l
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Cam is now for sale... $250
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Wait! What?
I seem to recall quite a bit of discussion about flat tappet cams and high compression ratio. I have even seen your boat run.
How did you end up with this cam installed? Were you running this when we met at the Avi?
Since you have been running it, have you had any reversion issues?
What gear have you been running? Does it show signs of wear? FWIW, I would run a bronze gear.
I think your high compression needs more cam to be pump gas friendly.
Joe
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Wait! What?
I seem to recall quite a bit of discussion about flat tappet cams and high compression ratio. I have even seen your boat run.
How did you end up with this cam installed? Were you running this when we met at the Avi?
Since you have been running it, have you had any reversion issues?
What gear have you been running? Does it show signs of wear? FWIW, I would run a bronze gear.
I think your high compression needs more cam to be pump gas friendly.
Joe
This a whole different engine. 496 with aluminum heads and flat pistons.
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My 468 has been running great, though.
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This a whole different engine. 496 with aluminum heads and flat pistons.
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Why do you want to change it?
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My new question is: going from the current roller cam specs to the cam recommended by Dan'l, can i run the same springs?
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Fear of reversion. I posted the cam specs
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Gonna put the 468 in my lil bros 19ft hallett bubble deck.
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This a whole different engine. 496 with aluminum heads and flat pistons.
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My new question is: going from the current roller cam specs to the cam recommended by Dan'l, can i run the same springs?
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Before I open this can-o-worms further, what RPM were you turning with the last cam?
Flat top pistons? Do you know your compression ratio? It might be in the low to mid 8s.
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I never ran the 496. I bought it used from River Dad.
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