need help on cam
 

zz502 replacing cam,heard lost on crane 731,would like comment on isky 696275/284 or crower 01403 lm .best pick out of three? why? thank in advance.

Re: need help on cam
 

If you could list the timing and lift specs of each we could help more. I assume the heads are edelbrock rect port. What is your wot rpm target?

BT

Re: need help on cam
 

awesomerott, I have two HP 500 cams for sale if you are interested pm me.Jeff

Re: need help on cam
 

the crane is 587/610 lift 226/236 at .050 duration 112 lc.isky is 553/578 lift 228/238 at .050 duration 112 lc. crower is 563/586 lift 229/237 at 0.50 duration 110 lc.had a ultradyne 284/292 # stamp on shaft (need to be replace corosion on it.fond trace of water in motor). just but this boat only ran it 4-5 hr,it 's a Awesome 2600f/x approx 4000 lbs,boat ran 84mph on speedo at 5400 rpm,bottom was poor.motor as stock aluminum head oval 110cc 2.25 int/1.88 ex. angle on valve being done.9.6/1 comp with 850 cfm double pump,intake was team G #7524 ,changing for air gap or sugestion welcome,it as headear(wet) d'ont know make,(lithning may be?).want to improve bottom and at least same wot rpm if possible.running only fresh water.

Re: need help on cam
 

I would be looking at a 242/ 252 @ .050, I like the 110 lobe separation for a stronger mid-range, I would degree it in at 102-104. Just an opinion.

Re: need help on cam
 

why so much duration and the change of timing ? i've been told to stay whith a duration under 240 if possible,just curious.

Re: need help on cam
 

Advancing the cam would bring the hp/tq back into a useable range. My opinion would be to pick a lower duration cam and load it straight up.

BT :cool:

Re: need help on cam
 

if enderstood,stay below 240 and degree centre?

Re: need help on cam
 

We ran a 238/ 248 .585 lift cam in a 454 it ran fantastic. The old LS6 454 was 242
at .050 it was a solid. We ran a 256/[email protected] in a 502 for at least five years, it
ideled right around 1000 rpm, it would rip the arms off a skier, and run right up to
6000. Most company cam cards, Comp, Crane, Crower, will tell you to install a 110
lobe separation cam at a 106 lobe center, Ultradyne would say 104. I've had my best luck at 102, I ran them anywhere from 98 to 108 just to see the difference.
On a new rebuild with a new chain and gear it is possible to end up with a couple degrees of wear. This is only an opinion, just what I've seen and done over the last
20 or so years.

Re: need help on cam
 

[QUOTE=GPM]ideled right around 1000 rpm, it would rip the arms off a skier, and run right up to 6000. Most company cam cards, Comp, Crane, Crower, will tell you to install a 110 lobe separation cam at a 106 lobe center,

If you plan to run up to 6000rpm, those durations are great. I see what you are saying about cam timing now GPM. My cams are 111 seperation angle with a recomended centerline of 107. That is considered 4* advance ground in. I really meant when you deviate from the recommended ICL is when you are suboptimizing the cam timing.

BT :cool:

Re: need help on cam
 

We are always trying for that last hp in a useable range, the 454 motor pulled very
strong to 5600 it ideled at 850.It was in at the manufacturers recomended center line. The cam has to be right for the combination. I'm only sharing what I found, we could run a bigger cam, advance it a couple of degrees and make more power in the same rpm range.
I'm not talking 20 degrees bigger, and it's not a good idea in a blower application.
And like the other guys say it's only my 2 cents. Good Luck.

Re: need help on cam
 

i definitly want stay under 6000 may be 5800 rpm max,i sure d'ont want sacrife lo and mid range. what about lift ,like to hear your opinions, what about company,any preferance,why?appreciated. :frog:

Re: need help on cam
 

As far as heads go awesomerott , I run edelbrock rect port alum heads and they are about the best value (inexpensive) you will find in a marine head with good marine valves. Others says AFR heads are the ones to beat flow wise. I never ran them personally. Sizing the lift on a cam you should consider the airflow of the heads at the desired lift and pic a cam with lift that will complement the flow values at that max lift. That's how I do it anyway.

BT

Re: need help on cam
 

that's why i was looking at a cam close to stock for this set up. i don't want to change the heads.money is an issue in this case.just trying to find best cam for this set up.i'm pretty happy whith the top end i had, but low to mid range was not wright.and not knowing all the specs of the cam i pulled out,(i measured lift on it about .600 lift int and ext.)i thought i pick something in between.i don't think the problem was the cam,but since i have to change it,i need to by from different company.of course it would be nice to improve all around.

Re: need help on cam
 

awesomerott
Do you have the flow #s or the exact part number of your heads?
Bob

Re: need help on cam
 

gm p/n 12363390 cast#12363391 semi-open/110cc int.vol.(cc)290

Re: need help on cam
 

anybody ever run the isky mentioned above?

Re: need help on cam
 

may be i should give the gring # instead rr-275/284 HR for gen v1


as for the heads that all i know,got the #'s from GM perf. parts book.
may be someone else know the flow# on these head.

i'm stil a bit confuse on wich cam to use.regardles of my choice do you think it would be good to instal a quick access timing cover to fine tune the power ramp ?

thank's for the info. realy appreciate all your comments.

Re: need help on cam
 

Info on "desk top dyno" thread
Bob