The Stovebolt Site Forums The Shop Area Engine Shop Screwed again

The '55 early GMC I bought a couple weeks ago has a freeze crack in the block. It is a great sounding engine and doen't smoke a bit. And it matches the title.

I'm thinking about trying to patch it up enough to use around the farm. Anyone had any luck, good or bad, trying such foolishness? I'm thinking arc weld with ni-rod, braze or J-B weld. What do you think?

The crack is about 6 inches long and doesn't pooch out. :confused:

I'd try JB Weld myself, but arc could prolly work - heck, if it's always on the farm maybe that powdered StopLeak stuff would be enuff - and leave the rad cap loose?

Bill

I think most states are good about changing titles from the engine number to the body number - it isn't much different than just having a typo on the title. Here in Missouri, you just have to have a police officer look at the data plate and the title, and sign off on the correction. That way your title would still be valid for the truck, and you could swap engines.

Yea Squeeze, that stopleak might work if I never got it on the road. Now that you mentioned that I remember hearing oldtimers tell about stuffing steel wool in the hole and let it catch the stopleak. I don't think this one is even big enough for steel wool.

GMCpanel, Yea I know the different number won't be much problem but I was upset because I've seen very few trucks where the engine and title match. Most people don't bother with it.

Texas was very helpful when I needed to prove that they titled my truck by the engine number instead of by the body number. Here in Washington I had to have the truck inspected to get the title changed. They wanted to assign a new number, but I asked that they use the body number instead.

As for the crack, I'd start by trying the least intrusive fix, and working toward the more drastic. I don't think you have a pressurized cooling system in the first place, so stop leak may take care of the problem. I'd save drastic action like welding for after the other approaches failed.

Just my two cents...

stop leak on the inside, jb weld on the outside.. should do the trick.

Welding the crack will require a full teardown to the bare block, and the services of a very good welder experienced in cast iron welding. It's necessary to pre-heat the block, weld about 1/2" at a time, and peen the weld to stress-relieve it as it cools, then weld another 1/2", and do the peening again, etc. The metal will crack right beside the weld as it cools if this isn't done.

I'd suggest grooving the crack out just a bit with a die grinder, plus grinding the metal bare of paint for about 1/2" on each side of the crack. Get some Devcon Epoxy Steel, which is much harder and more durable than JB weld. Mix it according to directions, and apply it about 1/4" thick over the crack, tapering to nothing at the edge of the ground-smooth area. Lei it cure overnight, then dress the patch with the die grinder and repaint.
Jerry

there is another product you can also try, it's Block seal, you do a flush of the system, then pinch off the lines to the heater core, run the engine up to over the normal operating temp, if having to blocking the air flow throught the rad for a few min till the leak stops. Then drain the cooling system and let sit for 12 hours, its suppose to even fix head gasket leaks, and another product is Iron tite.

I worked a while at a machine shop, they would drill the ends of the crack, peen a small steel rod in the holes(stops crack from spreading), then V-groove & fill with regular JB weld-the quick type was not liked for this. Some of these engines for tractors, etc. were made of unobtainium so had to fix what you had. Brian

cletis there are a lot of really good suggestions here. I think this is what I would do. drill the ends of the crack to keep it from spreading. Then I would drain the cooling system including the block. Then I would cap off the upper hose outlet. Attach shop vac to the Lower hose and see just how much air you suck through the crack. If it is a lot then you will need a smaller source of vacuum. If it only sucks a little then fine. I would then mix up some epoxy and apply using the vacuum to help "draw" the epoxy into the crack. Good luck and let us know what you end up doing.

Thanks for all the responses.

I'll go the stop drill and epoxy route first and see what happens. I suppose that Devcon Epoxy Steel is available at parts outlets. I'll try to put a little V in the groove with the die grinder and plug the stop holes with steel rod.

Brian, your vacuum idea sounds good. Even though I don't think it's possible to get the inside of the block clean enough for the epoxy to stick, having it in there should make the patch stronger. And if it still squirts a little I'll have more meat for the stop-leak to stick to.

Whoa, That thing is split from a**hole to appetite. I started cleaning on it today and it's worse than I thought. I'll have to pull the manifold to get to the middle of it. Now I'm thinking about pulling the engine and dropping in a rebuilt 248 that is earmarked for my '54.

I couldn't find the Devcon steel epoxy. I found their clear epoxy and their "metal patch and fill compound". I bought the latter. It is premixed in one tube, not epoxy. Anyone tried it?

I agree 100% with hotrod lincoln. A needle gun is an excellent method of relieving stress in welding cast iron. Always prep thoroughly as suggested. Doesn't matter how long the sucker is, this method works. If they used this method during the repairs of the liberty bell, it would never have to be retired!
If you have $ to burn, there are various cold-apply powdered compounds. These are applied dry & heated. But a few ounces usually cost over $100!

I pulled the engine and did an epoxy patch. I'll get some pictures up soon.