Marine Camshaft Differences

I know a marine camshaft is required for a marine application but I got in a debate with a coworker who insisted there is no difference and that an automotive camshaft would work fine because he use to race trucks and the camshafts he used held up fine under those conditions so there is no reason why they wouldn't work in a marine engine. I told him my understanding is a marine camshaft is ground differently to compensate for the relatively high rpm's in a marine app.

Is there any other reasons why a marine camshaft is required rather than a standard automotive camshaft???

Re: Marine Camshaft Differences

I told him my understanding is a marine camshaft is ground differently to compensate for the relatively high rpm's in a marine app.

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Nope,......

Other than you've got that Slightly Backwards,.........

You're Right........

There are several differences, but Basically,.....
Marine Cams are ground to produce the Most Torque, at the Lowest possible rpms......

that an automotive camshaft would work fine because he use to race trucks and the camshafts he used held up fine under those conditions so there is no reason why they wouldn't work in a marine engine.

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Ayuh,............ With that Said,......
Just because it Worked,.......
Doesn't mean it's the Best Grind for That Application......

Re: Marine Camshaft Differences

he use to race trucks

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and I'll bet he wasn't using standard automotive cams either! Tell the guys he's an idiot and needs to stop talking about subjects he doesn't know anything about.

Chris...........

Re: Marine Camshaft Differences

Blend the two responses you got and you've got close to the whole story. There are some camshafts available from the manufacturers that are "auto" cams, but will work in a marine engine. As long as those cams are for "high torque" applications. Anyone building a race truck motor, wouldn't be using the same camshaft as a guy building a boat motor. Racing cars/trucks, tend to demand rpms over 5500, where boat engines tend to like to be under that.

Re: Marine Camshaft Differences

Don't the marine cams have little to no overlap to help prevent water ingestion?
Thought I read that somewhere.

wncrjb

Re: Marine Camshaft Differences

you can use a truck cam in a boat motor... they are soo close you'll barely be able to tell a difference... I know I've read it on here somewheres saying truck cams are almost identical....

Re: Marine Camshaft Differences

JoChek219 said:

you can use a truck cam in a boat motor... they are soo close you'll barely be able to tell a difference... I know I've read it on here somewheres saying truck cams are almost identical....

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Usually they will be referred as an RV grind. Some times you'll see a Marine/RV grind listed. Either way your getting more torque at lower RPMs.

Re: Marine Camshaft Differences

hello,

in general, an automotive sbc cam will work in a sbc marine application, for example. the big issue is going to be the rpm range that the cam will produce its hp and torque. however, a long duration cam such as in drag racing, and that can include trucks, is not suitable for a typical marine application. one could be found in a fuel hydro, and that still is a marine application. well, of sorts...

profile centerlines, centerline separations, adv durations, 050 durations, lift, rate of lift, ramps, profiles, lifter types, etc... all will come into play to tailor a cam for a particular engine application.

the subject is simplified here, however it is a very complex subject.

regards

lakester

Re: Marine Camshaft Differences

hello,

if u really want the full story, i suggest u contact a cam company such as Crane Cams in Fl, or Crower Cams in Ca. they will have tech people that specialize is assisting with cam selections in all sorts of motorsports.

of if u want you can research a marine application engine or cam from GM. i think their annual parts book has them in there. then take a look at the cam specs. look up the cam as an individual part and ck the specs it lists. then compare to, for example, RV cams.

but u have to understand the dif tween adv durations and 050 durations and what they mean. u have to understand how lift varies with duration. time off the seat, time on the seat.

imo, the simplest route is to contact one of the cam companies mentioned. ck them online. no doubt lots of info available from either. both are major players in the performance cam field domestic and internationally.

they were there when ed iskendarian was a "household" name...

regards,

lakester

Re: Marine Camshaft Differences

Ayuh,.......... As noted, Cams are a Science,+ probably just as involved as Rocket Science at that......

To simplify it as much as possible,.......
If Cams were scaled from Mild to Wild,........
Marine/ RV/ Truck Cams are at the bottom of the Mild side of the Scale,......
And,........
Fire Breathing Race Cars are at the Top of the Wild side of the Scale..........
As you climb that Scale,........
Lack of Torque Down Low is the 1st Issue to arise,.....
Next is Reversion.......
And, of course it gets Worse from there....... Marine motor wise.....

Re: Marine Camshaft Differences

"would work fine" ~ needs definition
for example:

My V6 Chevy engine was rated 120HP in the cars it was in, with the stock automotive cam and throttle body injection.
With the marine cam it makes 185HP with a 4 BBL carb.

The ONLY difference in my boat engine besides timing curve, intake and exhaust from auto version is the CAM (ok, and brass core plugs)

So, it would probably "work" with the automotive cam, but I would rather have my extra 65HP for the $99 I spent at Summit for my marine cam
55% HP gain for 99 bucks....
hmmm