99ssleeper

iTrader: (98)

I disassembled an engine because the ringland on #7 broke from too much nitrous. The engine also had used an MS3. 3 of the 8 pistons had marks on them from the valves hitting, some worse than others.

The heads were stock other than PRC golds and Titanium retainers, rev limiter was up near 6800 or 7000.

I can get pics later on. Just some info for you all.

CABRO

iTrader: (1)

did you over rev.... spray through redline?

99ssleeper

iTrader: (98)

i bought the car as a roller with the damaged engine, so i dont know.

PREDATOR-Z

sounds like unstable fluctuating valvetrain (maybe float), those cams are tight so any sneeze on the valvetrain parts and wacko.

Paint_It_Black

iTrader: (1)

Exactly. That's why minimum recommended clearance is .080 intake and .110 exhaust. And with excessive float, you can STILL kiss the pistons. Cut it closer to the "well it's not hitting at idle it must fit fine" clearances, and all it can take is 1 over rev or missed shift and OOPS you've got eyebrows in your pistons!

PREDATOR-Z

Yeap, but most low to mid 230 cams with 112 LSA are borderline to that, a 232 112+4 is .07x, a 230 111+4 is .07x just to give a couple of exemples.

brad8266

iTrader: (23)

Wheres all those guys here that always tell me that PTVC really isnt that big a deal?

Me personally would not run any cam other than like a 224 ish one without some cut in the pistons and clearances verified, just my personal preferance.

Dave 96TA

iTrader: (10)

Just run it at 7000rpm for a few minutes then change out the valves and you've got DIY flycutting

taws6m6

iTrader: (37)

so does that mean my 232/234 112+4 is extremely close to having possible problems? I dont rev the engine past 6500

PREDATOR-Z

No, but it is borderline on the safe street PTVC. As long as your valves are controled correctly, no float, it is very safe; this is why it is important to keep an eye on the valvetrain and do yearly checks on spring pressures and such.

ls2 bait

iTrader: (11)

my 232/234 on a 112+0 hit numbers 1 and 3. not bad but u can see the marks. this was with a .040 gasket and stock valve drop. i also rev to almost 7k.

LS1crazy01

iTrader: (14)

Wow thats crazy. I am very thankfull of this information now. Most likley I will be doing my heads at the same time as a cam but this is good stuff to know. I gotta let my buddy that just put his MS4 in know about this. I hope everyone that preaches big cams read this, its good stuff. You wouldnt happen to have any pics of this tear down would you?