PDA

View Full Version : Need minimum piston to head and piston to valve clearances.


drew416ex
06-10-2013, 08:44 PM
Im rebuilding my engine and had to shave the head a little so now I want to clay it and make sure everything is still good to go. Only problem is I lost my specs for all of this. Does anyone know the minimum piston to head and valve clearances? Thanks!
81dasher81
06-10-2013, 09:09 PM
how much did you deck the head?
drew416ex
06-10-2013, 09:37 PM
how much did you deck the head?

Only .003", but I guess I should mention I'm puttin in a higher compression piston also. I'm having to bore and they don't make a 88mm stroker piston. So I'm custom making one to work. I just don't know my allowable clearances.
81dasher81
06-11-2013, 06:51 AM
what compression? i really dont think it should be an issue
Blodg
06-11-2013, 08:43 AM
It definitely could be an issue with a stroker and custom piston so you are smart to clay it. I have done that years ago with my 500cc stroker 350X motor and have some notes somewhere. I will look it up when I can but I am thinking maybe .030" or .040" but don't go by that until verified.
81dasher81
06-11-2013, 10:10 AM
oh im sorry, i didnt realize you were doing a stroker.. then yes it def could be.. my bad
Blodg
06-11-2013, 03:10 PM
On the Duncan Racing website it says: Minimum clearance is .060" from valve to piston at peak lift.
drew416ex
06-12-2013, 11:53 AM
On the Duncan Racing website it says: Minimum clearance is .060" from valve to piston at peak lift.

Just got a email back from Mickey Dunlap at four strone tech and he told me Intake valve needs .060 clearance ,ex valve .080 and the deck needs to be .040 so I guess I'll go for that. Thanks for the help everyone.