So I found my culprit that has been feeding my exhaust antifreeze... I took down my model "B" block today to find an old repair. Someone stitched the crack and them threw a weld over the top. The stitch was not overlapped and was never properly sealed. So with what I had here in the garage, I tried to preheat, braze, and postheat only to find more cracks... I was able to cover most of the cracks and smooth it out with a bur-bit, but I am not totally confident with the fix... Does anyone out there know of a product that I can use to coat over the top of this. (Epoxy/Sealer???) They are hairline cracks that don't deal with a lot of pressure, I just want to run this motor till I upgrade to something later down the road. ***** I can't stitch where all of the cracks are.. so if it can't be brazed, I'm wondering if a epoxy or sealer will hold up to the temp. Anyone have luck with this, or can recommend a product?? Thanks, Matt
In the past , I have successfully used " Marine-tex" epoxy to seal cracked marine engine blocks. It should be available on line or at West Marine among others I doubt it will hold up to exhaust temps ??
Seems like there's a dev-con epoxy product that will hold up to the heat. Shoot.........these guys that use it to build up the inside of there intakes and other race applications....I bet they make sump'in! 6sally6
Temp is the issue... It really is just for a skim coat. Thanks for the suggestion. I will have to look into it more. Thanks Matt
Its just for a skim coat that doesn’t deal with really any pressure... there has to be something out there. I’m sure I can run it as is. Just would like to seal it the best I can. I’ll have to look them up! Thanks Matt
No personal experience with it yet but this product was recommended to me by a local welder when I asked about welding a crack on the outside of a boat exhaust manifold. The outside of my manifold (water side) will never get as hot as what you're working with though. https://www.jbweld.com/product/j-b-extremeheat
I seen that. 2400degrees!! I’m pretty sure my brazing rod melts before that.. If so it can withstand what I need.
The problem area is well exposed. You may consider finding a diesel engine repair/ rebuild shop. Competent shops often weld, braze or use some specialty alloy solders to repair cracked or broken cast engine components. They have proven methods of proper preheat to prepare the effected area for welding and to reduce oil impregnated into the effected areas as well. The shop will post heat to relieve stress and reduce chances of re cracking. Proper cast metal repair is a multi step process. You would probably have to tow the vehicle to them or bring the motor only. There is a shop here in the New Orleans area that has helped guys with these issues for many years. Just a suggestion, something to consider.
I agree with you 100%, that stripping it down and taking it to a shop is the best and most professional fix. I just don't want to strip the motor down all the way and do a rebuild if I will be swapping it out down the road. it ran strong before. I would like a car this next year to putt around on. It won't be a hotrod till a couple years doe the road. just not in the cards.. I planned on building up this motor if it was a good block, so I'm glad I found this before I invested more money in it. so it is kind of a blessing in disguise... Matt
So I am goin to give this a try! Plan is that I will smooth this out in a couple days and reassembled the motor back to the stock condition, once all the gaskets and miscellaneous parts come in. The next step would be to run it on and off for maybe a couple hrs. Pull off the exhaust manifold and inspect the area. If it doesn't hold, then I’m on to either a motor swap (if I can find a good A motor,) or who knows.... Id rather enjoy the car this cruise night season. Haven’t had a runner in 10+years, been playing with the bikes for the past couple. (This can be a little science experiment for all of us. And I guess a product review!) Thanks to all that helped. I will keep you guys informed! Matt
Did you drill a small hole at each end of the crack to stop the crack from continuing to run, before you brazed it?
A temporary repair that may last a couple years with minimal effort may be liquid water glass. Sodium silicate. Years ago I worked at junk yard. We had an old loader with a cracked head. It would dump water into exhaust. We drained all antifreeze, added water and a quart of liquid sodium silicate. Started it and let it run. At first it was steaming like crazy from the cracks in the head. Slowly over the course of about 25 min, it was steaming less until not at all. The old loader run like that with daily use for another year.
The the cracks were in places I could not get to, The place I covered had already been stitched, but not properly... More crack were seen from other places after heat applied. Some were pre existing that we not able to be seen after cleaning. Im sure the heat added to the stress.
You might try a product called Devcon. It come in several variations from liquid epoxy to a epoxy putty. Stuff when cured bonds very well to ferrous surfaces and is very tough. Do a google search for Devcon and it is sold in a lot of places.