The Stovebolt Site Forums The Shop Area The HiPo Shop Leaky Offenhauser dual intake???

To put the Offy 2x1 and Fentons on my 261 I had to grind the Offy to get it to clear the Fentons. I plumbed the Offy for water heat using one of Langdon's plates and some brake line and also had the two zinc plugs heliarced.

I've still got what I'll call a weepy leak- It isn't much of a leak but after the engine's been running for a while there are a few drops of anti-freeze on the front bottom of the Offy.

The water isn't coming from the heli-arced plug and it's definately not coming from the lines or the plate bolted to the bottom. I think I might have ground into the water jacket on the bottom but can't see any cracks. If I could find the crack I'm sure it could be repaired, but I can't seem to find it. Is there anything I can do short of replacing the manifold?

Next time I would definately have the mounting surface of the fentons milled at an angle so they tilt inwards toward the engine rather than grinding the Offy. I would also buy the Offy from Stovebolt rather than Patricks or elsewhere 'cause Tom Langdon heliarcs the plugs on all the manifolds he sells and those other guys don't.

D.I.Y. crack detection can be done with L.P.I. (liquid penetrant inspection). Sort of like Magnaflux in a spray can. Most welding supply places will have the stuff. Here's a link showing how it works and what the cans look like. You need 3 spray cans. Cleaner, penetrant, and developer. Good luck.

http://www.magnaflux.com/files/products/overview/Spotcheck_Materials.pdf

NM51,

I would call this "my kind of luck". It seems that It will have to be removed for repair...that's obvious. Would it be possible to take it to a automotive machine shop that pressure tests aluminum heads, and have them locate and weld the leak.

There is a shop down the road from me that does a lot of Toyota and Volvo engines. They have a tank and various blanking plates to test the aluminum heads for cracks for a "go/no-go" determination.

I believe they have TIG capabilities to deal with repairable cracks.

It actually might be cheaper to invest in a new manifold..sometimes you have to bite the bullet.

Stuart

Try some of that aluminum powered stop leak. I had the same problem and it fixed it.
Tom

Thanks for the ideas!

I think the leak detection and repair might cost as much as a used Offy, but I'll check around.

For now, I think I'll try the Aluminum stop leak powder that they make for radiators etc... If that doesn't work I'll keep an eye out for a used manifold and just keep adding water to the radiator until I find one.

I've read that the trick to the stop leak pellets/powder is to drain your cooling system and fill it with water before adding the powder and then flushing it before adding the anti-freeze again.