Air bubbles at head nuts

H

hydropower

Member
Hope to solve a mystery. I recently started up a new rebuild. 1941 block bored 20 over 3 3/16, mercury crank, stock cam, adjustable lifters, egge pistons. The block was decked .010 best 59A composite head gasket with 2 coats of k&w copper cote.Which was still very tacky when I installed the heads never used it before? Used Edmonds custom heads that were in good shape redomed the chambers .050 for piston clearance. Stock studs with hardened washers permatex aviation form a gasket to seal threads into block. Torqued head nuts to 45lbs in 3 stages. The compression on all 8 cly is 135lbs.Motor has about 30minutes of run time and I have retorqued the heads to 55lbs when cold because of this problem. Did not help!
I am getting small, size of a bb to 3/8"air bubbles intermittently from about 3 studs on each head. No coolant leaks and cannot detect any air bubbles in radiator.
Any ideas or suggestions?
Thanks for your help.
 
As noted - possibly some studs are leaking just a bit. But I agree with you, is a bit strange that you don't see coolant? I've only seen situations where coolant seeped just a bit - and usually it quits after some run-in time.

As Alan noted - make sure you get it into a car and broken in (if you haven't already).

If Weeping Studs: I've found that in most cases after a few runs, it will 'seal itself'. Otherwise, you'll need to pull the heads and redo the studs. I use a liquid teflon sealer on my studs - seems to work really well.

Something Else: The only other thing that I can think of is that some of Edmunds heads were known for porosity - maybe there is a chance that it is leaking come compression through the aluminum? Or, some slight compression coming by the head gasket to the stud? Just some other wild-*** guesses to consider - especially since the heads have been redomed.

D
 
Thanks for everyone's responses I think Bored and stroked might have found the answer
"The only other thing that I can think of is that some of Edmunds heads were known for porosity - maybe there is a chance that it is leaking some compression through the aluminum? Or, some slight compression coming by the head gasket to the stud? Just some other wild-*** guesses to consider - especially since the heads have been redomed."
I think I will run it for a while and keep an eye on it Like Alan suggested. It is in a bare frame with a seat bolted to plywood. Should be interesting driving through the neighborhood. Thanks Mike
 
"Should be interesting driving through the neighborhood."

"Splain" to the cop what you are doing, in a nice tone, and he probably won't give you a ticket. At least the one that stopped me didn't, but he didn't like "that thing" (28 Buick) on the road w/o lights, seats, body, etc etc.
 
ford38v8 said:
That ^^ but don't panic yet. It can seal itself in due time, just watch it for a while.
Don't run your new engine too much on the test stand, install it and drive it to break it in.
Click to expand...

I have a car buddy that has been working on a restoration for over 50 years ,on and off still not finished. He has run the engine at idle most of those years so it will stay freed up. I bet he would be shocked if he had an hour meter on it.Hopefully this will be the year he finally drives it.
 
You must log in or register to reply here.
Back
Top