Piston/Valve Clearance

Aubrey N Bruneau · 09-10-2011, 03:46 PM

Robert... these fellows CERTAINLY know more than I do here, so I'm just put'n this out there, as an example of where it can be.... if you're an idiot.
I run a 108 lobe-sep cam, installed 4 degrees retarded. There was just too much gained from this confifuration, for me to turn my back on it.
However... the idiot part
I have about .065" clearance on the intake... and, uh.... .038" on the exhaust
! !
My exhaust lobe is much "calmer" than the intake lobe, so my control problem still emminates on the intake side, which has required some pretty outrageous spring pressures in order to rectify.
I don't use a "chip" in my burnout, and refuse to let the engine go past about 5500-6000 during it.
I have yet to connect my two step, to properly control my launch RPM, so I'm letting out the clutch as the engine accelerates throught the 5000-6000 range.
I shift at 7000-7100, go through traps at 7200... IMMEDIATELY drop into neatral and let engine idle.
Maybe it's a combination of my "old style" techniques, that's letting this ridiculous exhaust piston/valve clearance survive ?

09-10-2011, 03:46 PM	#8
Aubrey N Bruneau Member Join Date: Sep 2003 Location: South Eastern Alberta, Canada Posts: 311 Likes: 6 Liked 7 Times in 3 Posts	Re: Piston/Valve Clearance Robert... these fellows CERTAINLY know more than I do here, so I'm just put'n this out there, as an example of where it can be.... if you're an idiot. I run a 108 lobe-sep cam, installed 4 degrees retarded. There was just too much gained from this confifuration, for me to turn my back on it. However... the idiot part I have about .065" clearance on the intake... and, uh.... .038" on the exhaust ! ! My exhaust lobe is much "calmer" than the intake lobe, so my control problem still emminates on the intake side, which has required some pretty outrageous spring pressures in order to rectify. I don't use a "chip" in my burnout, and refuse to let the engine go past about 5500-6000 during it. I have yet to connect my two step, to properly control my launch RPM, so I'm letting out the clutch as the engine accelerates throught the 5000-6000 range. I shift at 7000-7100, go through traps at 7200... IMMEDIATELY drop into neatral and let engine idle. Maybe it's a combination of my "old style" techniques, that's letting this ridiculous exhaust piston/valve clearance survive ? __________________ Aubrey N Bruneau 6409 C/S 62 BelAir sport coupe, 409 HP 409