LS1C5Vette

iTrader: (11)

I just want to hear some ppl on here admit that they are running smaller than recommended PTVC (.080I, .100E)? I am at .080 on the intake after flycutting the I side but am at .080 also on the exhaust (no flycut), I would cut it a bit but do not have the correct size cutting tool, would/do you guys think .080 on the exhaust is ok? Heads are TEA stg 2 LS6 milled .020 2.04I and 1.57E valves, stock MLS gasket.

JPH

iTrader: (2)

What is your Int. clearance? Exhaust is a little on the tight side, and about sure te intake is even worse.

.070+ min. int and .090+ min. exh. is what I shoot for, otherwise you go at your "own risk" and hope you stay off the rev limiter?

LS1C5Vette

iTrader: (11)

Intaake is right where it should be at .080. If I could find the Isky flycutting tool asap for the exhaust I would cut it .030 deep but I have no clue where to get one

Dragkid1917

iTrader: (2)

yo man we have the same cam and im wondering if i can swap to a thinner gasket. I have the 241 heads, do you know the stock 233/239 PVC?

chrs1313

iTrader: (24)

get an adjustable timing chain and advance it a 1.5-2 degrees...every degree is around ~0.0065

vettenuts

iTrader: (4)

But his intake will go down. Given a choice (other than neither), I would rather the intake be on the short side than exhaust.

LS1C5Vette

iTrader: (11)

Yea I see what you are saying, I clayed it again and its a very small amount over .080, I would say .082 but I went ahead and put the heads on as I do not have a cutter to flycut the exhaust side. I measured my pushrod lenght and got 7.300 with no preload so I think I am going to order the 7.350's...

vettenuts

iTrader: (4)

I would go 0.075" preload.

Jason 98 TA

iTrader: (4)

I've run .040" / .055" one time on my own car. While I don't at all think it's a good idea, I never had any issues with it. Your on the tight side of what guys like to see, but I doubt you have any problems.

LS1C5Vette

iTrader: (11)

They do not have the 7.375's in stock, if it comes to it and its too loud I will just order longer ones and take a small hit and sell the 7.350's

redtail2426

iTrader: (10)

i have never personally trusted the clay method.Instead i use the feeler gauges between the rocker and valve method.Much more accurate,if done properly.I would say you dont want your exhaust that tight is its an m6,if you miss a shift,and have a mechanical overrev,you may have a problem.The intake valve on the other hand is fine.I would just locate an isky tool and sleep better not worrying about the engine staying together,but thats just me.

The Alchemist

iTrader: (19)

If I am understanding correctly, you take the point to where the valve is closest to the the piston, and then add shims till the valve touches, and then measure the thickness to get PtoV clearance? That seems the best way as you wouldn't have to pull the heads to take the measurements. All you would need to do is swap the valve spring to a softer spring and then back again afterwards.

studderin

iTrader: (28)

I would run .040 on a auto car.
Not on my m6 car. The syock cam/valvetrain had contact on a 2-3-2 so problems form it I even fly cut later). Also run a good valvespring, even more then needed, if your under good amount of room =.100

And watch the valvetrain weights (aftermarker "better" parts that weight a lot more then stock)

vettenuts

iTrader: (4)

I believe the OP did both ways, the clay was a confirmation of his prior measurements with a feeler gauge. I think the fact that the two methods came out 0.002" apart shows he was pretty careful taking the measurements.

LS1C5Vette

iTrader: (11)

Just bumping this thread to let everyone know how its been at those PTVC numbers. I have ran the car a couple times at the track with the rev limiter set to 7300, (I was trying to make 2 passes without having to shift into 4th gear, it did not help my time so I set it back down to 6700). Also I did the "3rd gear into 2nd gear" shift and saw my rpm gauge fly into the black zone on the gauge, I babied it home and thought the worst, I did a cyl leakdown test @ 90 psi on all cyl's amd had NO leakage other than the small normal air slipping past the rings into the crankcase. Also I have smacked the rev limiter a lot since then and its been great, I will however be changing the valve springs out after 15 or 20k miles. Also my numbers and 1/4 mile time on the set-up are below.