Can I take a cylinder head from the junkyard and install it right away, or would the timing be off?

[Josh P]

Rust is like cancer. It returns, spreads and grows. Factory coolant never changed or pure water will do that. I'd be confident the head could be ran as is. The JB Weld will protect the metal as much as it will help seal.

 

[rfishi]

I'm basically adding tiny bits of JB weld, letting it thicken up a bit, then gently running a razor blade over it to make it flush.

To be honest, I didn't prep the metal before applying the epoxy, but the small area I was applying it to didn't really have rust, the rust started a bit more inside the hole, so hopefully I'll be okay.

 

[Josh P]

That looks good.

 

[Turdle]

Don't disturb the epoxy until it cures, then, sandpaper on a block to level it down.


Shaving with a blade will pull It off the repair area..slightly but it will pull.

You'll just have to wait overnight for this one. Hopefully you didn't use the quick set version . It's about 25 percent strong as original.

 

[410Fortune]

This is at the “dead end” of a water jacket port. Water will be flowing into this cavity and then through the small hole in the gasket. Scale and crap buildup in these cavities over miles. That epoxy is trapped. Even if it did break free from adhesion it is still not gonna go anywhere but sit there until the next lucky wrench jockey pulls this head. We just don’t want it to break free and clog the hole

 

[rfishi]

I put the epoxy on yesterday and smoothed with razor blade, and waited overnight.

Now this morning I applied a tiny bit more, and plan to wait til tomorrow and sand it down.

I used original JB weld, it says its 5020psi strength.

 

[Josh P]

People with very old engines, where replacement parts are no longer available have to resort to this type of repair. I read about a guy that had a classic BMW with a cracked cylinder head. Oil was pouring out the side of the head onto the exhaust manifold. Some mechanics recommended a JB Weld repair, the guy thought they were joking. He tried it and the leak was gone. I've used it as body filler on a steel bumper. It never cracks like bondo eventually does.

 

[410Fortune]

I fixed a cracked 4.0 ohv w jb weld it held for years
My dumbass overtightened the oil pressure port in the side of the block
Later would learn that’s npt thread and tapered. Cracked the block
My friend Brett rescued me. He drained the oil cleaned the area, dried, let sit overnite
Cleaned and dried some more then carefully applied jbweld and threaded in the fitting. Let it cure for the think two full days

That held for like 8 years until my
Dumbass saw it was weeping a little bit of oil and tried to turn it. Jb weld came right off
I replaced that engine by the next Monday so I could get to work

Impressive repair ability on a cast iron block, on the outside of the block in an oil passage. Without jb weld this repair is not really possible and to hold as long as it did… thank you jb weld and mostly Brett!! Hahaha

This is where engine conversions come in, when an old engine and part is obsolete but the vehicle around d it is worth saving it time for a transplant
With 5.0 explorers the explorer rots out around the 302 lol

 

[Turdle]

It works for powder coating. Conducts, smooths, takes the extended heat.