Valve to piston clearance
Thread Starter
Melting Slicks
Joined: Mar 2002
Posts: 2,164
Likes: 7
From: Beringen
Valve to piston clearance
I need to recheck my VPC on my engine after i change to my new cam. I wonder if the method by replacing the spring with a soft spring and then pushing down on the valve is a good method opposed to dismantling the heads (which i prefer no to do).
Drifting
Joined: Dec 2005
Posts: 1,360
Likes: 3
From: NORTHEAST
That should work fine but remember intake valve to piston clearance is the closest 5 to 7 degrees after TDC as the valve is chasing the piston and we have been .045 on the intake before and no problems but if you could have mroe that would be good and exhaust we have been .080 and zero problmes.
Le Mans Master
Joined: Feb 1999
Posts: 6,172
Likes: 11
From: somers, ny
If you're that close, i suggest you set it up with the valve train that will be run and check it by tightening the rocker nut at 5-10 degrees before and after TDC for exhaust and intake respectively. Reher Morrision's website has detailed instructions to check it. Assuming your radial clearance and valve angles are correct, you shouldn't have to remove the head.
On a recent engine, i had zero p to v clearance with the soft springs, but it cleared with the springs that were to be run and had no issues after 2 seasons.
On a recent engine, i had zero p to v clearance with the soft springs, but it cleared with the springs that were to be run and had no issues after 2 seasons.
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Put the checking springs on and rotate the motor and check, as stated watch before and after TDC, shoot for .100" exhaust and .080 intake 
Le Mans Master
Joined: Aug 2001
Posts: 8,145
Likes: 1
From: Bradenton FLORIDA
If you're that close, i suggest you set it up with the valve train that will be run and check it by tightening the rocker nut at 5-10 degrees before and after TDC for exhaust and intake respectively. Reher Morrision's website has detailed instructions to check it. Assuming your radial clearance and valve angles are correct, you shouldn't have to remove the head.
On a recent engine, i had zero p to v clearance with the soft springs, but it cleared with the springs that were to be run and had no issues after 2 seasons.
On a recent engine, i had zero p to v clearance with the soft springs, but it cleared with the springs that were to be run and had no issues after 2 seasons.
