Hot Rods Ouch! - New Offenhauser Heads Leaking

before I retired, I worked for a company that used a lot of aluminum castings. every once in a while we would have porosity problems. we sent the castings out to a company that impregnated a Loctite product under pressure, that stopped the porosity. If you would like the company name, I could get it for you. nick.

 

Flathead Jack lists sodium silicate in his catalog although I've never tried it. Here's a link:

http://flatheadjack.com/73.html

 

I wonder if it can still be done after the coolant has contaminated the pores. Do you end up with a layer of loctite over the entire piece requiring blasting, machining and polishing to make it usable again?

 

Man I believe you may have done this to yourself.... Not every piece is made to be polished. Those spots have a fairly thin casting to start with...

 

Thousands of flathead heads have been polished, some multiple times. There's no reason that they should be that thin or porous. The heads are defective. I would try to deal direct with Edelbrock if you run out of options.
I have had very good luck with Alumiseal. I wore a hole in an aluminum radiator because of those Mickey Mouse plastic ties that come with electric fans. One can of the sealer , let it come up to temp and then drained the system. That was 5 years ago and not a sign of leaking since

 

Mendtite cooling system sealer by Zecol will solve your problem quickly and easily. It works in anti freeze and pressurized systems and won't plug your radiator or heater core. If you do a google search you'll find Subaru, Mazda and tractor forums where it has been used successfully. I've used it for 40 years.

https://usahardware.com/departments...-additives/mendtite-radiator-sealer-16oz.html

 

Sorry but this is all wrong, you can't polish away 5/16 or more of alloy, plus the leak is in beads == porosity.

 

How does one go about directly contacting Offenhauser? To my mind they would be the ones to contact. People have been polishing those heads since Day One so I find it hard to believe that the act of polishing is the culprit.

 

well he either polished it right down to the water passage. Or the whole casting is oozing liquids. (because the casting is porous) If that's the case he's gotta seal it either polished or not. I think that that's the case. And he would have had the oozing regardless.
-Pat

 

Why is it so hard for some people to admit those heads are bad....defective.....no good.......poorly cast......icky or whatever term you like. He didn't ruin them with a simple polishing. They should be a quarter inch, or more, thick in that area. There was core shift or a poor pour.
Like Sidevalve and I suggested, contact the manufacturer and see what your options are

 

now there's good advice, do that first and let everyone know the results of that conversation.

 

Good question, I was never able to find a contact number or better yet an e-mail address so I can show them these pics.

I appreciate all the advice of stop-leak products, but I’m hesitant to try any. I’ve only used them a few times, and they either didn’t work at all or the fix lasted a couple months. Plus I'm nervous about plugging up my new Walker $$$$.

Leaking this badly simply after break-in does make me wonder if they'll get worse or crack after years of heat cycles.

 

If you are able to find contact information pass it along if you will.

Good luck and I hope your problem can be resolved to your satisfaction.

 

I've had very good luck with stop leak products. Had a BB 427 with a head gasket leaking (badly). Used a high quality stop leak product and went though the whole procedure. It worked great and that engine was driven hard for years after that. We're not talking about putting a lot of gunk in the engine to plug the holes, these are products specifically designed to repair leak issues. It does take quite a bit of effort to go through the process, but well worth it from my experience.

 

At this point, what is needed is a cheap and easy try to seal, like with sodium silicate carefully used.
Since the heads are an old purchase and have had metal removed it is impossible to prove they were junk when delivered, and of course new heads would have the dreadful cast finish they have now. Only reasonable thing is to try a sealer system and hope for the best.
If I remember correctly, the Moroso stuff was once specifically advertised for use on excessively ported drag race heads...

 

water glass!

 

Bruce,

You mention "sodium silicate carefully used". Would you like to explain how to use it carefully?

 

I'd use some sort of sealer with Gingerroot in it. It does the job, but isn't so permanant that it's hard to remove when you tear the engine apart.
Every overhaul I do gets a dose (usually GM Cooling Tabs) to make sure the headbolts and such don't weep.

 

Which dealer sold you the heads? Contact them first and then contact Offenhauser at 323/225-1307.

 

Phone Offenhauser themselves and see if they want to save face...
(323) 225-1307

 

At my job we use die-castings that are sealed with a loctite casting sealant to fill porosity. You can probably get some through Fastenal, or industrial distributor, but you would need to devise a means to pressurize.

 

By "carefully" I just mean with good cleaning of the system first, in this case probably followed by letting it leak some running clean water to clear out any contamination in porosity, then following directions from supplier to get it in there, pressurize, get up to hot, etc.
If this is just porosity and not a casting that has been ground down to nothing it seems an excellent hope here.
I think this was a bad casting, most likely, but what supplier is going to take back a long past purchase that has had metal removed at point of leakage??

 

cadillac has been using block sealer since the 90's when they started using alloy blocks! discovered this after buying one at auction everyone thought head gaskets were blown and guy tells me they don't use them just block sealer and every 5 years it needs more added. bought many cheap cadillacs and added sealer and problem solved! parts guy said it was water glass with something added that did nothing but keep patent from being infringed on.

 

Offy had a porosity problem with their flathead heads a number of years ago. A motor I built with new Offy heads from Speedway leaked in the dome area in a number of cylinders I found the flaws after pressure testing the new heads but that was after they had been installed on a motor that filled with water when you tried to start it.
The heads were purchased many years before the motor was ever run. I contacted Offy directly and talked to Tay Offenhauser who agreed they had a porosity issue with a run of heads he sent me a new set of heads to replace the bad ones he also made good on the extra time I had to put into the customers motor.
Offy at the time would only do a small run of flathead heads at a time so I had to wait until the next run of heads were cast that took some time but at least I was able to correct the problem. Call Offy directly it worked for me and they know there's bad heads out there Speedway and Offy know there was a problem but kept it a secret wonder how many motors were damaged from these leaking heads?