Speed Pro 2295F questions...

[rampage_82]

Ok I know that they are heavy, but I already have them, and they were not damaged, when I spun my rod-bearing, which my machine shop diagnosed finally. I was only using half-grooved main bearings....yeah I know I'm an idiot . However, if I run these pistons, will my motor survive, if I set the rev-limiter at 6,500?

Also does anyone know how big of a camshaft you can run with these pistons. I have 906 heads, which have an 82cc combustion chamber. I want to get .600" lift, with .258 duration @.050, and 300 adv.duration, is this possible, or will I have to flycut the hell out of these pistons?

[thatwasfunny]

You should not be spinning rod bearings over not having full grove mains.
You will possibly spin bearings if your rod bolts are stretching/or are crap.
You say 6500 rpm, but the cam you mention sounds more like 7500+ rpm.
Is it a roller?
Sounds like you'll need valve clearance all right.

[owatajrkiam]

Most forged pistons have a valve relief depth of .2" for the intake and .15 to .16 depth for exhaust! Now depending on a lot of other factors ,they are usually pretty generous in allowing a pretty high lift cam!. .600" lift is a whole new ballgame though! Without even knowing the details,i would say it's gonna' need flycutting somewhat!. I couldn't find the specs on what these weigh,...do you know!. These are definately a strong piston though, as my buddy hasn't melted em' down w/ nitrous yet!. As was stated,..half groove vs. full groove shouldn,t of made a difference!. Full groove is nice to have for sustained rpm,but for just the occasional bashing,where you don't run to the floor for 10's of minutes or hrs. on end or a real high rpm,i wouldn,t sweat it!. I've seen 8,000 rpm small blocks live w/half grooves!. I suspect there was another problem!

Glen

[rampage_82]

Well, my poor unbalanced 440 was way over 8,000 (hence the new ignition box, with rev limiter), because the truck went airborne three times in 200 ft. Also I ran extremely loose tolerances on the bearings, I.E. .004. Mix that with the 6 pack rods, and 3/8" standard oil pickup (rear sump truck pan), I think it was a combination of things that did me in...and I had 2 comp cams go flat on me as well.. BTW these pistons weigh 835g's. ... and the rods were resized, and I was running ARP rod bolts..

Ok the cam I'm wanting to run is a Howard's Mechanical Roller, the power range is from 3000 to 6700 on a 440.

[rampage_82]

Heck this roller cam, isn't that much bigger than the Mopar .590" solid or some of the Ultradyne solid stuff, has anyone here put a big cam with these pistons?

[rampage_82]

Actually I've found several 440's built with these pistons, the 906 heads, and the .590 MP cam. The MP cam seems to open the valve sooner than the roller cam I found?

[rampage_82]

Sorry to do this, but

TTT

I'm just asking if someone has put a large cam with these pistons.

[nhdriver]

I ran those pistons w/ a .600 lift Lunati. I did have them flycut not too deep. I don't think you could run them without flycutting them

[thatwasfunny]

Not to say thats your goal, but If you wanna rev 8,000 RPM it's time for oiling mods.

[thatwasfunny]

Also loose the 6 pack rods and get some that are stronger [in the right places]
and that when combined don't weigh as much as 1 of your cylinder heads.

[rampage_82]

Originally Posted by thatwasfunny

Also loose the 6 pack rods and get some that are stronger [in the right places]
and that when combined don't weigh as much as 1 of your cylinder heads.

already done... the H-Beams are on the way....and I have a Mallory Hyfire 685, that the rev limiter is going to be set at 6,500.

[rampage_82]

Originally Posted by nhdriver

I ran those pistons w/ a .600 lift Lunati. I did have them flycut not too deep. I don't think you could run them without flycutting them

thanks man that was what I was wanting....