LawmanSS

iTrader: (19)

Here's my problem (names have been withheld):

Company A sold me a set of camshaft specs based on data I provided about my setup (CR, head flow, etc.). From these specs, I purchased a custom grind from Comp that came out as an XE-R 226/230 .600/.601 110 + 4. Company A guaranteed me that I would have no P to V issues because, "the piston will be 2/3s of the way down the bore when the valve hits max lift." Installer B, who currently has my car, says that there's no way that this cam will work with my heads (MTI SII LS6 milled .030). Installer B has a very good reputation and I don't question his assessment. Anyway, my options are to scrap the cam and buy another one ($400 lost + $400 for a new one) or to flycut the stock pistons. Is flycutting a safe option? Those who have done it on stock LS1 pistons: any problems? FWIW, Installer B doesn't usually recommend flycutting cast pistons, but said many have done it successfully! Whew...sorry for long post, but need help!

HumpinSS

iTrader: (1)

Why not isntall teh cam and do the valve drop down method to make certainly sure there are no issues

BergerMan

There isn't anything wrong with notching the pistons. I did mine without a hitch. LGM has done dozens without any problems. The max you should cut is about .070", but I doubt you will be close to that. Just have your "mechanic B" install everything and check the clearance. You won't know till you put it together. DO NOT TRUST WHAT ANYONE SAYS ABOUT P-T-V CLEARANCE UNTIL YOU PUT THE PARTS ON YOUR ENGINE!!!

LawmanSS

iTrader: (19)

Thanks for the suggestions...I'll ask installer B to test it to verify P-V before I lose my mind and panic...however, he gave me the indication that he didn't believe it would even be close in this case.

LawmanSS

iTrader: (19)

Any other thoughts or experiences with flycutting?
Thanks.

blue2kss

Jay from Absolute did mine with the motor in the car (I went with the G5X2 an 5.3 heads) i've had no problems with anything

robertbartsch

do a search much discussed on this about six months ago - tons of stuff on this....

..one of the sponsors rents a special head that has the valve seats removed.....you use it with the Isky flycutters and the short block in the car...

...Diamond piston guy said it does not mess the motor balance up because little material is take off....

Pro Stock John

iTrader: (34)

Did A know that you have .030 milled heads? .600 lift seems like a lot with milled heads.

LawmanSS

iTrader: (19)

They sure did...I told them repeatedly that I was warned about P-V issues with the heads milled .030. I was concerned with the .600 lift value myself and questioned them about it several times. They repeatedly said that P-V wouldn't be a problem. He explained that "most people confuse lift as the culprit with P-V clearance problems when, actually it's duration because the piston is 2/3s of the way down the bore when the valve hits max lift and that they always recommend the most lift that the heads will take."...since I'm still learning this stuff, I didn't question him...BIG MISTAKE!