LT 1 350 valve to piston clearance

[MR DERBY CITY]

Originally Posted by Ed Wright

Having raced 265" '55 & '56 Chevies, we damn sure flycut our flat top pistons for valve-to-Piston clearance. Mine was down 4 times by NHRA, three national records & once was protested, passed every time.

Ed, we are talking STOCK eliminator.....Alan is correct. I might add just watch yourself in the water....

[Ed Wright]

Originally Posted by MR DERBY CITY

Ed, we are talking STOCK eliminator.....Alan is correct. I might add just watch yourself in the water....

I apologize. The Stock rules are different enough from when I ran Stock with that '56, I should have kept quite. About all he can do legaly is move the cam.

I don't get the remark about water?

[TOSTO RACING]

I think he is referring to don't let it get away from you on a burnout. People tend to over rev a car in the water box.

As for vtp like Alan said above .060 .065 exh would be as tight as I've ever ran and it was okay for me. The intake is more forgiving. if I were you I'd advance the cam and get yourself some more exh clearance and less int in my opinion if you are worried about it .

Good luck with it.

[Ed Wright]

Originally Posted by TOSTO RACING

I think he is referring to don't let it get away from you on a burnout. People tend to over rev a car in the water box.

As for vtp like Alan said above .060 .065 exh would be as tight as I've ever ran and it was okay for me. The intake is more forgiving. if I were you I'd advance the cam and get yourself some more exh clearance and less int in my opinion if you are worried about it .

Good luck with it.

Need to use a rev limiter in the water. I run .040" on the intake side a lot, have run .035" and they never touched. Had clean intake pockets. No carbon. I've never run less than .065" on the Ex side. Right now, mine has .040" & .070". Nothing touches.

[Dan Fahey]

Curious. Why more Clearance on the Intake vs Exhaust. ?

[rawhide]

Originally Posted by Dan Fahey

Curious. Why more Clearance on the Intake vs Exhaust. ?

Dan,

The exhaust valve runs much hotter than the intake and expands more.

Roland

[Ed Wright]

Originally Posted by rawhide

Dan,

The exhaust valve runs much hotter than the intake and expands more.

Roland

The exhaust valve and the piston are moving toward each other at the closest point.
Intake Side, the piston and valve are moving the same direction. You can run them closer.

[Bob Mulry]

Come on guys you all know the answer.............

Exhaust valve is closing and being chased by the piston and depends on valve spring pressure to stay ahead or be bent.......

Intake valve is opening and chases the piston down the hole and is controlled by the cam profile.....

[Dwight Southerland]

Originally Posted by Dan Fahey

Curious. Why more Clearance on the Intake vs Exhaust. ?

Should be more clearance on the exhaust than on the intake. Observe the relationship of the valve action in comparison to the rotation of the engine during the cycle. The piston is closest to the intake valve as the piston is approaching TDC and the valve is closing, so any contact will "push" the valve closed and/or the clearance will increase rapidly. For the exhaust valve action, the opposite is true. The piston is closest to the exhaust valve as the piston is approaching TDC and the valve is opening. The camshaft will push the valve into the piston and potential damage is greater.


There are other factors like what causes valve float, etc., but the above is generally true.

[randy wilson]

Originally Posted by TOSTO RACING

I think he is referring to don't let it get away from you on a burnout. People tend to over rev a car in the water box.

As for vtp like Alan said above .060 .065 exh would be as tight as I've ever ran and it was okay for me. The intake is more forgiving. if I were you I'd advance the cam and get yourself some more exh clearance and less int in my opinion if you are worried about it .

Good luck with it.

This^