| Author |
Message |
    
george leone
Member
Username: georgeinbeverly
Post Number: 52
Registered: 09-2006
| | Posted on Sunday, September 27, 2009 - 10:44 am: | 
|
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 |
Joseph J Levelis
Member
Username: joe_l
Post Number: 18
Registered: 04-2008
| | Posted on Sunday, September 27, 2009 - 12:11 pm: |
|
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 |
george leone
Member
Username: georgeinbeverly
Post Number: 53
Registered: 09-2006
| | Posted on Sunday, September 27, 2009 - 12:55 pm: |
|
This Link is to a .478 ,.502 lift cam
that Summit web site says is marine type
is it correct
http://www.summitracing.com/parts/CRO-32243/Application/?query=Camshaft+Usage%7c Marine |
Fastjeff
Senior Member
Username: fastjeff
Post Number: 6846
Registered: 09-2003
| | Posted on Monday, September 28, 2009 - 05:20 am: |
|
Fine for a Go-Fast boat; horrible for a cruiser.
Jeff |
Dan Finnelly
Member
Username: tolly_family
Post Number: 83
Registered: 07-2006
| | Posted on Monday, September 28, 2009 - 06:34 pm: |
|
What kind of boat? Most cruisers never run a 440 above 3000 rpm. Can't you get a stock regrind?
Dan |
george leone
Member
Username: georgeinbeverly
Post Number: 54
Registered: 09-2006
| | Posted on Monday, September 28, 2009 - 06:47 pm: |
|
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 |
george leone
Member
Username: georgeinbeverly
Post Number: 55
Registered: 09-2006
| | Posted on Monday, September 28, 2009 - 06:50 pm: |
|
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 |
Fastjeff
Senior Member
Username: fastjeff
Post Number: 6863
Registered: 09-2003
| | Posted on Tuesday, September 29, 2009 - 06:13 am: |
|
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 |
george leone
Member
Username: georgeinbeverly
Post Number: 56
Registered: 09-2006
| | Posted on Tuesday, September 29, 2009 - 10:35 am: |
|
WHAT CAM WOULD YOU RECOMMEND ??
FOR LIFT AND DURATION ?? |
Buehler Jet
Member
Username: bogdenz
Post Number: 67
Registered: 06-2009
| | Posted on Tuesday, September 29, 2009 - 11:41 am: |
|
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. |
Buehler Jet
Member
Username: bogdenz
Post Number: 69
Registered: 06-2009
| | Posted on Tuesday, September 29, 2009 - 01:48 pm: |
|
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. |
Peter McWilliams
Member
Username: pete31
Post Number: 67
Registered: 04-2008
| | Posted on Tuesday, September 29, 2009 - 10:24 pm: |
|
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. |
george leone
Member
Username: georgeinbeverly
Post Number: 57
Registered: 09-2006
| | Posted on Wednesday, September 30, 2009 - 10:15 am: |
|
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 |
Buehler Jet
Member
Username: bogdenz
Post Number: 70
Registered: 06-2009
| | Posted on Wednesday, September 30, 2009 - 10:23 am: |
|
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). |
Fastjeff
Senior Member
Username: fastjeff
Post Number: 6876
Registered: 09-2003
| | Posted on Friday, October 02, 2009 - 01:08 am: |
|
Especially in big block Chevies. They are notorious for sucking water in through the exhaust ports.
Jeff |
quik225
Member
Username: quik225
Post Number: 9
Registered: 08-2009
| | Posted on Sunday, October 25, 2009 - 03:14 pm: |
|
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 |
george leone
Member
Username: georgeinbeverly
Post Number: 58
Registered: 09-2006
| | Posted on Sunday, October 25, 2009 - 06:34 pm: |
|
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 ??? |
Fastjeff
Senior Member
Username: fastjeff
Post Number: 6987
Registered: 09-2003
| | Posted on Monday, October 26, 2009 - 06:15 am: |
|
Careful. Bad things can happen when you do that. I'd put it in straight up and down.
Jeff |
