LT 1 350 valve to piston clearance

Ed Wright · 01-01-2017, 02:10 PM

Quote:

Originally Posted by Dan Fahey

I do not think so.
265 55 Chevys sure wish they can notch their flat pistons to get some valve tolerance.

D

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.

MR DERBY CITY · 01-01-2017, 02:29 PM

Quote:

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 · 01-01-2017, 03:44 PM

Quote:

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 · 01-01-2017, 03:55 PM

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 · 01-01-2017, 04:01 PM

Quote:

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 · 01-01-2017, 05:31 PM

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

rawhide · 01-02-2017, 07:11 PM

Quote:

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

Dwight Southerland · 01-02-2017, 07:21 PM

Quote:

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 · 01-01-2017, 05:33 PM

Quote:

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^

B Parker · 01-01-2017, 09:40 PM

Hi Asking these questions I would assume your a newbie to stock. As Alan said did you check it the right way? In my younger years I might have run it with .060 but with the cost of everything today I wouldn't risk it. There are several ways to pick up that little clearance you need. I know it sucks but I would take the heads off and have a good machine shop cut .010 off the back of the valve. If possible move the cam a couple of degree's. What head gasket are you using? Have one custom made .05 larger but tighter on the bore so you don't loose compression. They don't cost that much. Good luck BP

01-01-2017, 03:55 PM	#4
TOSTO RACING Senior Member Join Date: May 2007 Location: DRAGSTRIP Posts: 893 Likes: 948 Liked 663 Times in 187 Posts	Re: LT 1 350 valve to piston clearance 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. __________________ 5664 GHI/SA 1985 CAMARO RED H/SA 1985 CAMARO BLUE I/SA

01-01-2017, 05:31 PM	#6
Dan Fahey VIP Member Join Date: Oct 2008 Posts: 2,128 Likes: 1,084 Liked 184 Times in 113 Posts	Re: LT 1 350 valve to piston clearance Curious. Why more Clearance on the Intake vs Exhaust. ?

01-01-2017, 09:40 PM	#10
B Parker Senior Member Join Date: Sep 2009 Posts: 852 Likes: 995 Liked 2,343 Times in 465 Posts	Re: LT 1 350 valve to piston clearance Hi Asking these questions I would assume your a newbie to stock. As Alan said did you check it the right way? In my younger years I might have run it with .060 but with the cost of everything today I wouldn't risk it. There are several ways to pick up that little clearance you need. I know it sucks but I would take the heads off and have a good machine shop cut .010 off the back of the valve. If possible move the cam a couple of degree's. What head gasket are you using? Have one custom made .05 larger but tighter on the bore so you don't loose compression. They don't cost that much. Good luck BP