I got my 416 heads on today. I adjusted the lifter preload on #1 then I went to adjust the next in firing order but when I was rotating the motor it stopped turning. I could feel the crank bolt turning. being afraid of stripping out the threads or worse yet breaking off the bolt I immediately stopped. I took the load off the lifters at #1 and turned the car over with the starter. It turns normally now. Would I be running into valve clearance problems with the 416 heads and my pistons causing the motor to stop turning? I have flat top pistons with valve reliefs in the top. I'd think with the smaller valves this wouldn't be an issue. Thanks

oh yeah on a side note how many cc's are those valve reliefs? I'm figuring -4ish.

 

What cam are you running?

What brand are the pistons?

Are you sure it's not just cylinder pressure that's holding you back?

Are the valve retainers hitting the guides?

Are the valve springs binding up?

Too many possibilities based on the little bit of info we have.

 

stock pistons

.470 lift

the valve springs are new and it's what was recommended for my cam

I didn't have any spark plugs in

 

anyone have any thoughts? This is actually keeping me awake tonight.

 

Stop turning your engine over using the crank bolt
https://www.thirdgen.org/techbb2/sho...hreadid=301205
Unless somethimg is wrong there is no way you should have contact. FWIW I run 416 heads, .040 quench, and a 230dur, 480lift cam with flat tops and have craploads of room.

 

after I bumped it over with the starter it wasn't an issue. I got all the preloads adjusted today and everything acts normal