Kurt vs. Heat Exchanger Nuts

[Rot 911]

Kurt: 11, Heat Exchanger Nuts: 1

Well it was a hard fought and long battle last night as I took on the dreaded heat exchanger stud nuts on the '86 3.2. Following all the recommendations of this board, the previous night I soaked all the exchanger stud nuts with PB Blaster. Then last night I got out the weapons for battle: my trusty oxy-acyetaline torch, long 8mm allen wrench and the wrench that came with the SSI's I put on my '72E. I heated each nut up to cherry red twice. I started with the barrel nuts thinking they would be much easier as the metric nuts looked like lumps of rust. Giving each a slight twist clockwise (tightening) I then slowly and smoothly untightened them. First one came off easily. Next, not so smooth then SNAP! Damn broke right off. Now worried I went and heated all the nuts up cherry red one more time. Back to the barrel nuts. The last four came right off. Now to the regular metric nuts, which I was dreading to attack due to the looks of them. First thing I discover is that when you heat rusted nuts up cherry red the rust pops like a firecracker and flys all over the place. One flake of superheated rust fell right down on the newspapers I had under the engine soaking up the oil drips. Damn, quickly put out the torch and stamp around on the newspapers putting the fire out. Glad the wife is up at the house. (I did have a fire extinquisher within easy reach). The nuts were so rusty I had to take a hammer and drift to get the wrench to fit down over the nuts. Maybe all that hammering did the trick because all six of the nuts broke loose easily. Once they were loosened up I could take them off just by using my fingers. Now back to the broken stud. Normally these things break off flush with the head or leave a 1/4 inch or so sticking out. When I took off the heat exchangers I found that the stud had broken off flush with the end of the barrel nut leaving me about 1" of stud with a good 1/2 inch of threads! Tonight I will try to double nut the stud out of the head. Once I had the heat exchangers off I got a chance to look at the exhaust valves. The reason for the whole rebuild was 60lbs of compression and 100% leakdown in cylinder 5. Here is a picture of the exhaust valve on cylinder #2 which had 190lbs of compression and 4% leakdown:

Here is the exhaust valve on cylinder #5. I can only imagine what the piston looks like:

[pete911]

I usually heat the nuts cherry red one at a time and loosen them while they are still red. They come right off this way.

Pete

[RickM]

I also tap the nut before and after heating with a hammer.

Nice pics Kurt. Keep us posted.

[MotoSook]

Wow Kurt..that second picture would scare the crap out of me, but then it might just be carbon preventing the valve from seating that is creaing a low compression (crossing my figers for you). Still, that's some scary dodo brother...

[Early_S_Man]

Very good pics, Kurt! Was the broken stud on #5, also? That valve may be burnt ... then, again, maybe not! Awful grungy ... maybe a leaking injector???

Looks like you may be getting off 'light' with just a top-end job, depending on what the #5 piston and cylinder look like!

[Rot 911]

Thanks for the feed back! Warren, the broken stud was on #2. I'm not sure if I have a leaking injector. #5 plug was very oily so I suspect a very worn valve guide, possibly bad oil ring and probably a damaged exhaust valve.

[goat]

Very good description. Excellent pics.
Looking forward to more.