Kevin in Atlanta

I am documenting what my heads looked along the way. The purpose of the exercise is using Greg's analogy clean and cap the decay as a preventative measure.

None to the 'decay' was on or near the fire ring.

Here's the heads with corrosion:






Here's after cleaned the corrosion with a brass detailing brush.








Here I have applied JB Weld in the circled spots. I dabbed the JB Weld into each cavity and then used a razor to remove the excess. The JB weld shrinks a bit. I am undecided if I will apply a second coat once the first application cures.




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joejoe

Will thermal differences between j/b weld and head material cause a problem?

FredR

Pitting corrosion is a bit of law unto itself so cleaning up the surface and doing what you have done is probably a very good measure to help seal the pitted surface and stop the corrosion from accelerating.

This type of corrosion seems to be quite common on our motors. My theory as to why this happens is when the engine sits too long without being run- the coolant does not circulate and possibly the anti corrosion chemicals get exhausted "locally" at the high points. Keeping the coolant anti corrosion chemical potent is important and I generally add a new bottle of water wetter after two years [it is has an anti corrosion chemical package in it] and then change the coolant after 4 years.

My heads were OK when they were removed 10 years ago but I had a corrosion spot on the inside wall of the water jacket- cleaned up the surface used something similar to the stuff you used that we use on pumps and the like.

Hope it works for you.

Rgds

Fred

Kevin in Atlanta

"Will thermal differences between j/b weld and head material cause a problem?"

Not from what i have read. I am not doing anything that hasn't been done before. Just documenting for future owners.

joejoe

Thanks Kevin, I may need something like this for my '81.

Shark_gts

JB weld is pretty good stuff. Looks like all water jacket you'll be fine. Another coat and wet sand flat for cosmetics

And not thermal expansion issues, JB weld is more flexible than the AL surface. Pitting provides great mechanical grip - even better if it was fine drilled or dremeled clean before application.

I fixed a cracked wheel rim with epoxy. The wheel edge was bent, so I heated it, last tap with the hammer the tire lip stress-relieved cracked. So I drilled like a dentist, anchor points, etc sanded with 40 grit. Applied epoxy paste and carbon fiber mat over the break. Sanded the next day, painted silver. Tires mounted ~ 3yrs ago and still running to this day. Solid fix.

mskar

I used JB Weld similarly on my Vanagon last time I had the heads off, that was 8 or 9 years ago, still going strong.

My understanding was that the guy who developed JB Weld developed it specifically for repairing cylinder heads.

Ad0911

which type of JB weld are you using? I see there is a whole range of them. I may want to do the same job as you have done here.

MainePorsche

The original JB Weld (twin tube) is good to temps over 500 deg.

http://www.jbweld.com/collections/metal

GlenL

I'd leave it alone. Those pits won't be a problem until the sun has exhausted all of its hydrogen.

ReDesign by FEATHER

Kevin, I use a product called high temp epoxy for much of what I do in mold and form making. My Plastics guy suggests that in order for it to be heat resistant it needs to be tempered with heat. I do that with a heat gun after it has cured over night or for a day or three. I heat it to just short of the point of it bubbling. Then when it cools it is very hard and will file and sand off to a powder rather than little clumps of gummy material. I suspect that process should be used with JB Weld as well.

Another thought I have is that I have used a different product in the past for mold making and that is called Devcon Aluminum F-2. It is a two-part Epoxy like material with a lot of aluminum in it. It is intended for mold making, but I wonder if it might be useful to fill your corrosion voids. Give that some thought. I would temper it also with heat if I were using it on Cyl Heads, and then finish it flush.

GlenL

I'd be afraid it'd come loose and make its way into the pump.

Cosmo Kramer

If it's used on the head it would have to break through the head gasket for that to happen.

Kevin in Atlanta

Heads after JB Weld and some sanding.

notaguru

Should be fine.

I did this on a 1956 Jaguar restoration, the head of which was in far worse shape. I carefully cleaned all surfaces, etched, neutralized, applied a high-temp epoxy*, and sanded lightly. The car drove for ten years and 25k miles with no problems - then I lost sight of it.

*The epoxy was claimed to have the same thermal expansion characteristics as the metal.