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When the idea of retorquing the head to stop my boiling over problem was presented to me I too was sceptical. I had tried every temperature thermostat and even tried using a restrictor plate, removed and inspected the distribution tube, checked and rechecked the timing and also went as far as installing an after market aluminum crossflow radiator (rated for 400hp) I wasn't loosing coolant, the head and block were planed and I would never consider using an old gasket. We used the factory recommended specs when tightening everything.
I had given up and had put the car in storage but thought I had nothing to lose and gave it a try.
From what I have gathered an air bubble can form blocking the flow of coolant causing overheating/boilover.
I wish I could better explain it but I have since taken the car on extended rides in fairly warm temperatures and have had no problems since.
It worked for me.

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Not really thought about it that way before. My experience with blown or leaking head gaskets was to find water in the cylinder and also water in the oil causing the oil to be milky brown in color. Also the bubbles in the radiator as well. I have pulled the plug out of a cylinder that had water leaking into the cylinder and found that the plug was super clean as compared with others where there was no leak. ( same engine ) The cleaning was due to the plug being steam cleaned to death. The plug looked new.

I agree that the compression pressure is much greater than the water pressure in the cooling system however the compression and power stroke only account for 1/2 the time. There is still the intake and exhaust strokes where the pressure is less.


Comments?? Where is Eric?? Always enjoy his comments.


Again only my opinion.

I had a honda that I drove for about 3 months on a leaking head gasket. What it would do is when the motor was hot, it would leak cylinder pressure into the water jacket, pressurizing the coolant, and blowing coolant pass the cap and into the overflow bottle. After a couple of days it would loose enough coolant, that it would then start to overheat. At which time, I would simple pour the contents of the overflow bottle back into the radiator, and I would be fine for a few more days. (It's what you have to do when you don't have the money to get it fixed).

The strange thing was that you could never detect the leak when the motor was cold, and it never leaked fluid into the cylinder. It was a one-way leak from the cylinder into the water jacket.

Kev, That is interesting. Don't think I ever had it happen that way to me. Always water in the oil or oil in the water. I can certainly understand the bit about not having the money to fix it. I think I've always been in that position.

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One thing to remember is that the cylinder when running isn't always under pressure, there's an intake stroke that operates under vacuum remember.

BUT....

The 1/5 a second that it's under vacuum isn't very much time for it to allow pressurized coolant into the cylinder, which is why it doesn't suck all the water out of the radiator right away. The likelihood of cylinder pressure going into the water jackets is a lot higher than coolant pressure forcing coolant into the cylinder. Both happen in a blown head gasket situation, but cylinder pressure into the coolant happens a lot more simply because more pressure is involved. 100+ psi Vs. 14 or so.

Think of it this way, try to inflate a tire that's at 20 psi to 35 psi with your mouth, pretty much the same thing.

Thanks BigKev, that seems to be about the best explanation I've heard yet. When I was driving it (pre-torque) I could almost predict when it was going to boilover. When in fact maybe it wasn't actually overheating (as one might expect when it overflows the overflow bottle) but building pressure and blowing by. The tempurature gauge never read accurately before (I assumed it was faulty) but now reads where it should be.
On another strange problem/fix,I have a Porsche 912 that kept on cooking generators, I tried everything to fix the issue...long story short it was the Optima battery...it made the generator work too hard to charge it...I replaced it with a regular 12volt and all was well. I guess something (almost) defy explanation.

Hi, I want to thank everyone for their comments on my combination of problems that I wrote about. After reviewing the comments, I think I will make a short, simple. separate post about each issue that I am seeking information on. So, thanks, and look for my new posts.
Larry

Hi, I have a 2262-9 with a 288 motor. I am looking into several items relate to overheating. A temp profile with a IR meter shows the hottest area is around Cylinder #8. I also have a failed #8 exhaust valve, probably because of the heat. I have the distribution tube out. It is clean and in good shape. There are 3 each holes on the valve side at the front that are 0.430" in dia, the rest on the valve side are 0.268" in dia. On the cylinder side, there is one 0.268" hole at the front followed by 2 ea holes that are 0.430" and the rest are 0.268" all the way to the end. These seem to be laid out and sized for a very specific purpose.
Questions:
1. What if I enlarge the last two holes on the valve side to get more coolant to the #8 exhaust valve?
2. How much should I enlarge the last two holes? I am aware that it will take away coolant from the other holes.
3. I am also very curious why the larger holes are up front and not in the rear, anyone know?
That's all on this post, I'll do another on a related problem.
Thanks,
Larry

Hi, I have the 2262-9 with a 288 motor. I have the distribution tube out and the waterpump removed. I am replacing the backing plate on the waterpump because it is eroded and the exit hole for the water is too big and not a good shape (it seems to have been modified poorly). The new backing plate exit hole is almost the perfect shape of the front of the distribution tube. But the distribution tube has two small tabs bent at right angles on the flat side of the tube. When I removed the water pump the distribution tube was flush against the block and the two tabs were captured between the block and the backing plate of the waterpump.
Questions:
1. Is this the correct position for the tube to be mounted with the tabs captured between the block and the backing plate of the waterpump?
2. Is it possible to mount the waterpump with the distribution extending through the backing plate and the tabs fitting inside the waterpump? This would make a much better fit and better transfer of water into the distribution tube but it might be very difficult to get the water pump/distribution tube mounted. It would move the distribution tube forward about 1/8" and slightly change the location of the water outlet holes inside the motor a small amount. Which is the correct way to mount it, #1 or #2?
Thanks,
Larry

#1 is the correct way to mount the distribution tube.
I'm not sure why some holes are larger than others but If it were me I would not enlarge them.