SoCal Jet Boats

Tech Talk => Engine Mechanical / Electrical => Topic started by: OutofTouch on February 10, 2022, 10:51:53 AM

Title: Cam Shaft Duration @.050 ?
Post by: OutofTouch on February 10, 2022, 10:51:53 AM

I think I have found my cam, still need to talk to Bullet on its specifics. What has me bothered a bit is the duration is 259 and 265 I/E. Is this getting  to close to the magic number of 275 degrees to cause the engine to start sucking water back into the chambers from the water injected headers? I don't need to hydraulic the engine.

Bob

Title: Re: Cam Shaft Duration @.050 ?
Post by: The_Dean_85 on February 10, 2022, 03:19:36 PM

Following, I always wondered the same thing


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Title: Re: Cam Shaft Duration @.050 ?
Post by: mash on it on February 16, 2022, 08:10:56 AM

I used an extreme marine comp cam, flat tappet, .575/.578 lift, 254?/264? at .050", with injected headers, without any drama.
Water valve is at the driver's seat.(Water wide open at the driver's seat wasn't enough to bother it at idle, either, and was gate valved at the pump too.)

Dan'l

Title: Re: Cam Shaft Duration @.050 ?
Post by: OutofTouch on March 02, 2022, 05:00:24 PM

Thanks Dan'l.

That's the information I was looking for. I use the Bassett control T and the cooling water is off at idle. The only time my cooling water hasn't been off was the day I had the spring break but I don't think the duration on the cam I was using is that high. Engine went together back in the 80's. May talk to Bullet to calm it down a bit. I am thinking the concern about reversion at idle when you don't have the velocity in the pipes, not at 3-5000 RPM's.

Bob