Reply With QuoteMaybe a roller?
Got a cam question for you guys...
The engine is a 540 at 9.5 compression. It is in a 22 Stealth pump boat. Boat web site
The current cam is a crane:
Crane camshaft. 236/246 .553"/.571" 114 hydraulic. 134561
The current setup is supposed to have pulled 631 @ 5600. I think that is fairly accurate as it spins a Dominator SS A at 5400 - 5500.
I'd like to gain some HP in the 5000 - 6000 rpm range (maybe run a 150 shot of NOS at some point also) so I was thinking about going to this cam:
Crane camshaft. 254/262 .585"/.600" 114 hydraulic 130721
What do you guys think?
Engine specs:
Merlin II cast iron 4-bolt main block.
Scat 4130 forged steel 4.250" stroke crankshaft. Clevite bearings.
Manley Sportsmaster 4340 forged steel rods. ARP rod bolts.
SRP forged aluminum pistons. 9.5:1 compression. Speed-Pro rings.
Merlin Hardcore Retangular port aluminum heads.
Manley Severe duty SS valves, in: 2.300" ex: 1.880".
Speed-pro lifters. Manley True Roller timing chain.
Crane aluminum roller rockers. Manley 4130 pushrods.
Merlin aluminum single plane intake manifold.
Hardcore Holly 870 cfm double pumper carburetor.
Hardcore HEI distributor.
Dooley 10 qt. jet boat oil pan.
Lightning water jacketed headers.
Maybe a roller?
If you went to that cam you would only see a minimal gain in rpm and speed would only be bumped up a few mph (2/3). Not really enough to warrant the change.....but, the N20 would probably gain 500 to 1000 rpm and 7-14 mph faster (guesstimite but probably pretty close).
Looks like all those parts can handle the nitrous (wish I had your engine)
.
I run a Crane 228 @ .050 with .544 lift, and it's rated for 3000-6000 rpm. Your cam has a is a little bigger, so I think as long as the rest of your parts can handle it (which it looks like they can), I would just add the n2o and have fun. I would go for the super powershot from NOS. It comes with 100, 125, and 150 jets. I would put in just enough juice to turn 6200 on the bottle, and leave the cam alone.
You will always gain performance with a roller camshaft verses a flat tappet. The reason being is the camshaft designer can now open and close the valve at much more rapid rate that he could possibly do with a flat tappet.
Not to mention less friction!..
It looks like my pick for a cam upgrade wouldn't have been much of an upgrade.
The consensus seems to be to investigate a roller cam or just leave the cam alone and go for the N20.
Thanks for the comments.
[ January 15, 2003, 10:33 AM: Message edited by: Shmoolie ]
Schmoolie, i am running a Crane solid roller 595/602 lift 236/246@ 50 112* it is under blower cams @ Crane website it is the smallest prod.cam they got on the shelf..it would also work good w/NOS too, cam is very easy on valve train parts and idles smoothly.just my 2*
Gopherrr
Schmoolie,
Speedamotive in california advertises a 540cu in. with10-1 compression that makes 750Hp up to 6500 rpm's. I talked to them a while back and they said that the motor makes a very flat torque curve up through 6000 rpms. The cam that they spec is a comp roller .636 lift 280-290 duration @50 with a 110 centerline. They use merlin steel heads. I realize the the duration is high but their thinking is that you are replacing lift with duration to fill the larger air requirements needed for a bigger cubic inch engine.
They claim that the motor idles smoothly. and is perfect for a jetboat application. Your compression is one point less and probably could use a 2 point raise in compression to compensate for alluminim heads. I would give them a call and see what their recommendations are for your application.
Based on the dyno sheets I would think their motor would push your A impellar into the 6200 range and then add a little shot of juice.
Just a thought. I am going to give them a try when I sell my 572's
Kojac
Shmoolie,
First off, did we pass you last year on the way to the river? Silver Durango, my boat... your rig looks familiar.
Second, I have a big roller cam in my boat that really woke the sucker up. .688 lift, 107 deg lobe centers. Talk to Wheeler about it, he knows exactly what it is. Motor is spinning 6000 right now with an Aggressor "B" (which loads like a Berk "A") and a preloader impeller. Spun a Berk "A" at 5800-5900 depending on conditions, timing and gas.
Wes
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