Amazing: Pisto to valve clearance
 

Ed curtis at Flowtech Induction told me the .566 lift cam he sent me would clear with stock pistons but i didnt believe it.

.566 Intake 218 duration
.566 exhaust 224 duration

I had my Canfield heads worked over by Abbot racing heads( 5 angle valve job, blended bowls, unshrouded valves and set up my springs for this cam.) and was not to happy when they told me they surfaced 15 thousanths of the heads. I thought great no way the cam will clear now.

I had .104 clearance on the intake valve and .184 clearance on the exhaust valve. This is with 2.02 1.60 valves

I measured piston to valve clearance using self hardening clay and some solid lifters. I repeated the process several times to ensure accuracy.

I fired the car up tonight and all is well. I should be flirting with the 11's with the head work and custom cam.

Obviously duration has more to do with clearance than lift.

Re: Amazing: Pisto to valve clearance
 

Valve clearance is in the realm of Black Magic, well a "dark science" at best. Oddly enough, your minimum clearance does NOT occur at top dead center. You're right, duration has alot to do with it, as does overlap and centerline.

Glad ya got it all worked out and the engine is happy happy! Let us know when you get that 11.80! ;)

Re: Amazing: Pisto to valve clearance
 

if ed told you it will work, it will work

Re: Amazing: Pisto to valve clearance
 

I am a believer. :cool:

I made 301 RWHP and 330 RWTQ last time I went to the dyno with a ported cobra intake, out of the box Canfield heads and the good ol E cam. I cant wait to see what I put down with the Trickflow track heat intake manifold, worked over Canfield heads and a custom FTI cam.

I am hoping to put down 330HP and 330TQ.

Re: Amazing: Pisto to valve clearance
 

well if it doesn't make those numbers, don't get too disappointed, just look at the average power in the useable RPM range. A lot of people get hung up on peak numbers, whichs is ok, but the average gains are where it's really at. good luck

Re: Amazing: Pisto to valve clearance
 

Zackly! Peak horsepower at 15,000 RPM isn't very usable. ;)

Re: Amazing: Pisto to valve clearance
 

unless you're in a honda :)