Cracks in the Oil Return Passage

[steve_wood]

Check this out. There is a small crack in the head near where the oil return passage is.

This is one my "spare" rear head. It used to be on the bike and it leaked a little. Not really serious, just an annoyance.

But I wonder if it's fixable.... I took it to a shop that does work on performance cars and they suggested trenching it out and filling it with Loctite 99913 (epoxy steel putty). Maybe even high-temp silicone which would stick to the sides of the trench as the metal expanded and shrank with heating and cooling.

Thoughts, comments or suggestions?

Crack3.jpg

Crack - Close Up2.jpg

[1950Panhead]

Easy repair, aluminum weld, the other ideas are temporary not permament.
I repaired a similar crack in a gear cover
Jerry

[Northman]

Steve,
I had this on a 48 front head......Tried several things like the aluminum weld and it held for a while and the started driping again, too much expanding and contracting, besides being a pain in the ass to reach it between the fins. I finally just put up with it because I didn't want to stick the cash into fixing it.

Northman

[steve_wood]

Jerry, Northman:

Are you guys talking about products like alumiweld or durafix i.e. aluminum welding with a propane torch, or are you talking about MIG/TIG aluminum welding?

I'm thinking that a big problem with alumiweld or durafix is that the heads would have to be pre-heated to exactly the right temperature for it to be a lasting repair.

Comments?

steve

[Cotten]

Steve!

It is the result of zealous over-torquing.

I fear that any attempts to weld are folly, causing more problems at great expense.

My choice would be to cosmetically cover upon the outside, and seal upon the inside.

The insert itself is still nearly as secure as it was cast.

If the crack shows within the combustion chamber, then that is something that can be welded.

....Cotten

[Huck]

Add me to the me too list.
rear head one fin up closer to the spark plug.
I found the problem after new guides over sized valves, a few heat cycles.
that sucks .
I now know you bubble test oil galleys first. Lets see the fixture for that!

[Northman]

Steve,
Yes I was refering to a quick fix without having to dig deep. The heads I had at the time were not cherry, but did the job. I left it as is in fear of creating more work and expense to resolve the issue. It already had the seats replaced once and were getting to the point of more work. I figured it would be more feesable to put my money to better use....like a head in better shape. They might have better stuff on the market now for repairs than they did then...don't know.

Huck your right seems, this old sand cast stuff you tend to chase issues.

Cotten too. I'm sure you have had your share of treats. Welding the stuff is tuff, you have all that impregnated oil to deal with and before long its just a gob of goo.

Northman

[58flh]

Pretty much anything you do will be a temporary fix,unless you weld it!. Ask yourself -is it leaking real bad or just an annoyance?---IF its just an annoyance I would just clean-it & apply some jb-weld or similar-(bandaid)!---Till it starts again.-BUT if the crack can be welded by putting a groove in & tigin it up to fill the groove &a little more-Then dremmel it to shape THAT should work. IF the crack can be seen inside the head!--THEN you can permanently do a proper fix!.--ITS your call BANDAID or WELD!---GOODLUCK---RICHIE----HEY I have seen BANDAID FIXES LAST ALONG TIME!

[Cotten]

Folks,

The cast-in insert is steel.
Welding the thin aluminum above it will only make a mess, and possibly compromise the insert.

My approach would be first to pressuretest it by corking the gallery at the headgasket, and then introduce high pressure from above with a conical rubber stopper.

The outside crack could be cleaned and filled;
My favorite isocyanate urethane would be my first choice, for its solvent and heat resistance, as well as its sealing qualities, even in the presence of oil.

The gallery itself could be sealed by reaming for a press-fit tube, if swabbing it with the isocyanate urethane alone was insufficient.

The gallery does not suffer high pressures when running.

....Cotten

[steve_wood]

Tom,

The crack does not propogate to the inside of the combustion chamber.

Any recommendations for an isocyanate urethane sealer?

steve

[Cotten]

Steve!

I use TNEMEC's "Omnithane 530", which is actually an industrial aluminum primer for water towers.
Unfortunately, it is only available in gallons or more, and hazmat shipping makes it expensive.

Here is where I sealed a leaking seam between the motorcases on a '49.

crakseal.jpg

The picture was taken a decade after it was applied.

Imron is also an isocyanate, but I have no experience with it.
I hear you can't use it straight out of the can like Omnithane.

....Cotten

[Huck]

I patched mine on the bike, gouged it out with a small hand file to bright metal, started the machine to get it hot, cleaned it again. I used JB weld, it flowed in pretty well on the hot surface, my leak went from an oily track on the head to a dirt gatherer. I like Cotton's fix, could you roll a piece of copper tubing into that galley? The way the tubes are rolled into the tube sheet on a heat exchanger?

[nmaineron]

If you have a good welder i would grind the fins down around the crack,clean the crack up real good and weld it up and build the fins back up.You will have to reshape the fins but the repair should do the trick!Good luck !

[rodklop]

Cotton, what you're saying is that you brushed a bead of Omnithane on the leaking seam of the engine to seal it ??
Is this the product that you have painted manifolds with that you have worked on in the past ??
Thanks for the info.....Rod

[58flh]

THE IMRON IS EXPENSIVE!---RICHIE