KevsfastZ

iTrader: (8)

Well I recently spun a bearing, when pulled the motor apart, I found PTV contact on every cylinder. This is the first time ever pulling the heads off, or even being in the motor besides the cam swap. I was revving the stock bottomed end to 6800. What do you think caused it? Car was MS4 with dual springs and a 150 shot.







Kev D

Nimitz87

iTrader: (17)

the weird thing is that it is on the exhaust side too...curious to see what the experts say.

Chad

Skeet Skeet

Wow that is weird. could it be weak springs? How old are the springs? Ill bet it pulled like a mother on the jug didnt it!

vettenuts

iTrader: (4)

Pretty big cam with less then minimum clearance on a stock setup. What were the original as assembled PTV numbers?

Nimitz87

iTrader: (17)

isn't this came suppose to clear stock setups though, that's the whole point.

I do not think he measured PTV.

Chad

Skeet Skeet

I thought that the ms4 was to big for stock heads? Im probably wrong but I thought that the ms3 was the biggest they made for stock heads. I dont think that he measured either. He could have over revved the car also and it would do that wouldnt it?

KevsfastZ

iTrader: (8)

I did not measure PTV at that point of install, I used stock length pushrods since the heads have never been off the car. I probably had 12k on the cam+springs.

98blueSScamaro

iTrader: (14)

stock push rods?????

vettenuts

iTrader: (4)

Pretty big cam with less then minimum clearance on a stock setup. What were the original as assembled PTV numbers?

Intercooler2

iTrader: (24)

He said he never measured.


If it's 6 speed maybe over-revved it. It's kind of a joke but they say the MS4 makes it's own reliefs in the pistons so not a huge deal. Nice pics

02*C5

iTrader: (1)

What springs and what push rods did you use?

Also why did you not measure PTV...don't tell me some one on the net said you'd be ok hu?

LS1TA385

iTrader: (1)

looks like valve float to me since the exhaust valves contacted the piston. the reason for that is because the exhaust valve is closing as the piston is coming up and if the valve springs are weak/overreved then contact is likely.

Skinny

iTrader: (11)

Valve float + high RPM with stock bottom end. I've seen the same kind of contact with the stock cam.

hcb1700

iTrader: (9)

12K miles+high revs+big cam+150 shot of nitrous=weak springs, which in turn will lead to valve float.