gemellocattivo.com

This makes a lot more sense than the other possibilities.

I'm glad you have the proximate cause figured out. I have no doubt you'll get to the ultimate cause. If it passed the clay test then had interference, I have to ask how you can be sure that there wasn't some valve float...

Damaged piston out, popped out the real springs on #1 put in my testing springs, head on the block.....no they most certainly do not hit so......but clearly they do hit so WFT?




I'm leaning toward saying I do not understand, but another 40thou should fix it. I need to drink on it a bit....

Go this drop box and scroll down to Piston to Valve clearance and down load the spread sheet.
Plug in your numbers and see what it says.

https://www.dropbox.com/scl/fo/d019rm1h ... o&e=1&dl=0

The critical spot is not TDC so you need to turn test it with light springs and a dial indicator on the bucket. I usually turn it by degree and push down on the valve and see what the dial indicator reads.

I can send the vise. A few thousandths more never hurts. Assume it hits and add .090 to the current pocket.

_________________
Wade Williams
Master Ferrari Tech
Restoration Tech
Engine Machinist
Fabricator
Racecar Driver

Clearenced in 2021? Didn't you just have new head gaskets made - at least different than you used before? Are they perhaps thinner when crushed? Also - didn't you add shims to raise the sleeves? I know that raising the sleeves doesn't modify the piston travel...but it is another change.

Have you flycut the heads recently?

-Tom

I'll try to hit everything but I'll lead with this. My focus at the moment is on timing chain stretch/slop during accel/decel or kick-back while cranking.  Its a LONG chain and the cam loads very high so it stretches, slop could easily change the timing by 5 degrees and that would be 20-30thou reduction in clearance. Make it 6 or 7 degrees and hot valves and they would hit with the clearance I have I think.

Then tightest intake valve clearance is like 7-8 degrees. Last night I checked at 5 and 10, and got .044, 7-8 is about 1 thou less.

The numbers I just posted were last night and very similar to what I saw in 2021.

My rule of thumb is .090 intake and .100 exhaust.
.040 is close

_________________
Wade Williams
Master Ferrari Tech
Restoration Tech
Engine Machinist
Fabricator
Racecar Driver

Much too close it turns out

Do you know where those numbers are from?

The dull work of tearing down the heads, 1 done.

First engine builder I worked for used that as his guide and I just accepted it.
An internet search returned .080 intake & .100 exhaust so it must be right.

_________________
Wade Williams
Master Ferrari Tech
Restoration Tech
Engine Machinist
Fabricator
Racecar Driver