opinions on this cam
 

Well I'm trying to get the motor back together for the weekend and ran into a roadblock.

To fix my current cam will take 2 weeks, to have another one reground will be 2 weeks maybe more. So I ordered an off the shelf Crower solid roller here are the specs:

.680 lift intake and exhaust
duration at .050" is 264/272
Lobe separation is 110 and it is ground on a 106 c/l

It was the closest I could find to my current one , which is :
.715 lift intake and exhaust
duration at .050" is 256/268
Lobe separation is 112 and it's on a 112 c/l

I have one more place that I can call tommorow that say's they can grind me a cam in two days but if they can't I plan on running that Crower one.

Chuck, see Crazyhorse's post in tech on "dyno vs boat hp".

lots of experience posted down in the guts of the thread about cams in that range and 680-700 hp motors at 5600...... maybe someone in there knows..... kaama (mark) has just built a 540 and the comments are flowing..

26;

The only thing I would be concerned about is Idle quality with a 110 LSA. Remember bigger motors like WIDER LSA's 114 is ideal. What intake and carb are you running, where do you Idle, what is "quality" and what kind of exhaust are you running? A buddy of mine had a 108 LSA in a 540 and it idled like ****.

Hi Rambunctious. Been around Muskegon Lake at all? Waterfoul called last night and said he can hit the rev limiter at 5200 with a light fuel load and one person. Seems pretty happy with the engine. He's thinking he'd like to bump the limiter up a little to see what it'll really turn. I told him to go for it. I'm kind of surprised he can spin that four-blade prop that high.

Dave, I hadn' t heard that latest..!! although my phone is blinking right now. he gets one call per day(kinda like jail LOL) I knew he saw about 4900 with a load of people. the engine must be freeing up a little. THAT'S AWESOME!!
It sure is awesome to see him smile again!!! great job on the engine. it sounds nice, starts great, and runs GREAT. he's a happy camper.

I was teasing chuck here (scarab26) that there is a reason they (merc, etc) don't build engines to run 5600 all day long. seems 5200 is a magic number for any sort of durability. Chuck said his engine would never survive our kind of running here on Lake Mich.
I guess Chuck you need to fill er up with fuel and check the ......lifters......

Dave, I was itchin to comment on your q about dyno vs boat power, but the thread drifted quickly into the cam specs. My opinion is one wants a cam that gets the most power output as possible at say 5200 , you mentioned kaama's cam lugging it with gobs of torque at 5200, but hp (as mentioned in your post) is simply torque x rpm. so if a radical cam makes 500hp at 5000 rpm on it's way to 5600or 6000, it isn't lugging any differently that another milder cam that happens to make the same hp at 5,000rpm at it's peak output. either one is making the same exact torque at 5,000rpm to get the same exact power (500hp)

just my opinion. (just armchair engineering again... :rolleyes: )

Dave, are you coming to the boat races. I am a race patrol, I could get you a front row seat:p


Jdnca1, 26scarab (chuck) has dry exhaust so no risk of water reversion. and it idles real bad.... I MEAN REAL BAD:D

sorry chuck for dilluting this so bad.....

Hey Rob ,
Sounds like your bored at work or wishing you were in LOTO !!:D
I'm sure it's only one of those !

Jdnca1,
My boat idles in gear at around 600rpm's with no loading up. So what do you meen by a "bad" idle ?
I have a Brodix intake and a 1050 Dominator.


I just got off the phone with someone that will do a custom grind and have it back to me by Monday. So I might just wait.

What I meant is if you had a borderline idle with a 112 LSA, a 110 LSA would make things worse. It looks like you were going up about 10 degrees in duration and coming down to a 110 LSA. That will have a bigger impact on idle "quality" than you might expect. I went from a 272/278 on a 114 LSA to a 280/288 on a 115 LSA to help keep the idle quality I had. (650rpm in gear) Even though I compensated, my idle is a lot choppier than it was and it does not idle as well. ;) But Damn it sounds nasty, you can tell its a BIG cam. :cool:

That cam sounds good to me. The lower lift will be negligible and the longer duration will probably push things up about 300 to 400 RPM. What is your compression? I have a used Erson 278/284 @ .050 on a 112 + 4 with .688" lift that would work well if you have at least 9.5:1. $50.00. I ran it in a 12:1 comp 496 with iron GM rect. heads. It worked well and pulled to about 6000 RPM. In a 540 with a little less compression it would work about the same.

Here is 26scarab's dyno curves. I don't know if you want to move the power band up anymore than it is. notice power still climbing at 6000!!!!:eek:

chuck, are you going to dyno this one? It will help with propping if this motor acts different, also I would like to overlay the two when you get the data

Mine was the same @6000 with the first cam I had in it, thats why I stepped it up. Now power falls off at 6800 vs 6100. Also remember a narrower LSA will produce a "peakier" TQ curve.