Why havent they marinized any dual overhead cam motors???
05-29-2009, 07:52 AM
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Why havent they marinized any dual overhead cam motors???
Does anybody know??? And what is the highest power DOHC engine you can buy???
05-29-2009, 11:13 AM
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Last edited by Dueclaws; 05-29-2009 at 04:38 PM.
05-29-2009, 11:51 AM
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MasterCraft and Cadillac had a very brief venture where they used the Northstar motor in their ski boats. It was a pricy upgrade, and other than bragging rights it did little else. Only a handful were produced and the project was scrapped shortly thereafter.
Toyota also used their Lexus V8 in their ski boat line called Epic. Also a short lived venture.
I think the low end torque of the pushrod V8s proved to be better for boat applications than the higher revving DOHC motors. Plus they are a lot cheaper.
Toyota also used their Lexus V8 in their ski boat line called Epic. Also a short lived venture.
I think the low end torque of the pushrod V8s proved to be better for boat applications than the higher revving DOHC motors. Plus they are a lot cheaper.
05-29-2009, 11:54 AM
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Volvo use to have that 4 cyl cammer that had like 170hp and spun to 5600 or something like that. It was only out for a few years though. Odd little motor . . .
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Throttles- Cleveland Construction 377 Talon
08 OPA Class 1 National Champion
08 Class 1 Geico Triple Crown Champion
08 OPA High Points Champion
10 OPA Class 1 National Champion ( happy now Ed! )
05-29-2009, 12:06 PM
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i saw some 903ci DOHC monster motor that made like 1200hp on pump gas for a boat, but nobody has made something in the middle like say 500hp????
05-29-2009, 02:28 PM
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I think the fact your all over looking is that DOHC engines are for the most part small cubic inch engines.
A boat liking or needing torque has nothing to do with what type of cam configuration or number of valves - the more cubic inches at low RPM produces more torque.
Look at a modern diesel like a Cummins 14 or Cat 3406 both examples of 4 valve heads where the more valves produced greater torque than the 2 valve head engines that they replaced (I know I'm dating myself to the 70's).
When you talk about Lexus, Ferrari or MB V-8's they are generally less cubes than a small block Chevy and you guys wouldn't put a SB in your 40' Skaters - right?
Also, look at the angles of the valves on a big valve push rod engine they are generally slanted as opposed to an OHC where the valve angles are flatter and two smaller valves make for better velocity than one large valve.
I studied all this in depth with the late Jim Fueling, his papers on valve geometry and flow are master peices but even he can't make low end troque without cubic inches.
A boat liking or needing torque has nothing to do with what type of cam configuration or number of valves - the more cubic inches at low RPM produces more torque.
Look at a modern diesel like a Cummins 14 or Cat 3406 both examples of 4 valve heads where the more valves produced greater torque than the 2 valve head engines that they replaced (I know I'm dating myself to the 70's).
When you talk about Lexus, Ferrari or MB V-8's they are generally less cubes than a small block Chevy and you guys wouldn't put a SB in your 40' Skaters - right?
Also, look at the angles of the valves on a big valve push rod engine they are generally slanted as opposed to an OHC where the valve angles are flatter and two smaller valves make for better velocity than one large valve.
I studied all this in depth with the late Jim Fueling, his papers on valve geometry and flow are master peices but even he can't make low end troque without cubic inches.
