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Camshaft valve lift 477 480 for Marine

G

georgeinbeverly

Contributing Member
Does It seem about right for a

Does It seem about right for a High torque mid range rpm Camshaft for a 440 v8 (23-233-4 comp cam)
1600 to 5800 rpm power range
I wanted to stay under the 500 lift cams
some web sites recommend .494 lift
original cam was .430 .440 lift
new lifters and springs also
 
You need to be careful here.

You need to be careful here.
Based on my experience with a 318
1-There are no free lunches /what you gain in mid or top end you give back at idle and in fuel economy.
2- you need to define rpm requirements.
3- a cam listed as 1600 -5800 rpm will have a rough idle and require substantial ignition timing advance to idle and may require limiting total advance.
4- as you increase lift you also increase duration and valve overlap. this has serious effect at idle.
think about a harley at a stoplight.

You could go to compcams website and get a recco.
Joe
 
Yeh I am thinking about a Smal

Yeh I am thinking about a Small grind
there is no Stock grind any more but Close to it
.430 .440 is About stock Size auto 1000 - 5000 Rpm
the only other choice is 800-4500 RPMs .424 .424

If you look at Marine Grinds They are all Large
Lift sizes for 454 and other big blocks
 
Its a 30 ft Single Engine Cab

Its a 30 ft Single Engine Cabin Cruiser

so I was thinking it needs a little extra to push

the 8000 lbs. at 3000 rpms
 
Whoa! Better stick with a mil

Whoa! Better stick with a mild camshaft or you'll be really sorry: bad gas mileage and higher than normal cruising rpms (to get the torque needed).

Manufacturers use mild cams and small ported/ valves heads for marine and truck applications for a reason.

Jeff
 
"Combining points made by Joe

"Combining points made by Joe and Jeff about idle and higher-rpm cruising, your boat could become a nuisance to operate at no-wake speed or in docking situations, for example.

You’ll likely have to idle higher to keep from it from stalling…..especially when in gear. When shifting, you’ll either be pulling the idle back to the range where it’s prone to stalling out or you’ll be slamming in and out of gear at higher rpms. It’s the reason why cam’ed-up cars require high-stall torque converters."
 
George - a quick afterthought

George - a quick afterthought and more of an answer to your question than my last post.....you may want to talk to the folks at Comp about an RV grind. These are typically very close to stock marine grinds (low-end/mid-range power). The most aggressive I'd go with a single engine in a boat your size would be a good-for-towing truck grind.

The duration (more so than lift) is where you don't want to go overboard...no pun intended.

I'd call Comp's tech line and tell the guys what you've got/what you need. They're good.
 
"I seem to remember a few year

"I seem to remember a few years ago, Edelbrock selling carb, cam & intake packages, & they had ones specially designed for R.V's, lots of low to mid range punch, just where we need it. Might be worth giving them a call too."
 
Comp Cams Recommends a 112 deg

Comp Cams Recommends a 112 degree Lobe angle
to decrease overlap and less than .470 lift
and 218/224 duration so A MILDER CAM

Less Aggresive lift and less overlap
it is a cruiser anyway

Most RV grinds are more aggressive ...
But I will take the Safe road
 
It sounds like they're doi

It sounds like they're doing right by you with that suggestion....especially trying to limit overlap (which can cause water reversion in a wet exhaust system).
 
Especially in big block Chevie

Especially in big block Chevies. They are notorious for sucking water in through the exhaust ports.

Jeff
 
"Forget the lift spec, duratio

"Forget the lift spec, duration is more important, along with LSA, it's what determines overlap and power range.
218/224 is a big cam for a 30' boat and 3000 rpm cruise goal.
The OEM 440 Magnum cam, which cam in the 440 Six Pack Marine motors, were 214/218 with a 115* LSA and .450/.458 lift. The M440 4 barrel motor (non-Magnum) had a cam with about 10 degrees less intake duration, or 204/208 with .425/.435 lift.
The largest I would go in a 30 footer would be something smaller than the size of the Magnum cam. Many aftermarket cams have a fast acting lobes designed for the larger diameter Mopar lifter, .904 vs .827 GM or .875 Ford.
Here's is one from Lunati that is between the Low Perf 440 and the Magnum in duration but should have Magnum power at lower RPMs due to the quick lobe ramps, should work good in a big boat.
http://www.summitracing.com/parts/LUN-60300
If you had a smaller boat, or wanted to cruise at a higher RPM, maybe the next largest which has duration comparable to the Magnum cam.
http://www.summitracing.com/parts/LUN-60301"
 
"Yeh Thanks ,,
I returned th

"Yeh Thanks ,,
I returned the comp Cam and ordered a Lunati
60300 a few weeks ago ,, 112 lobe separation
454 lift and 208, 213 duration
It was the 112 Lobe Separation I thought was the
most Important ... its also 4 degree advanced
some say to advance the cam 10 degrees ???"
 
Careful. Bad things can happe

Careful. Bad things can happen when you do that. I'd put it in straight up and down.

Jeff
 
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