Post #14 by ElPiloto » Sun Sep 23, 2007 1:06 pm
The best cure I have found for blown head gaskets over the years, is to make absolutely sure that both surfaces, head and block, are perfectly flat.
To find high and low spots, I use Dykem, a dye used in metal fabrication, and cover the head and block with dark blue or purple. Then, with a new, or like new, flat mill file about 2" wide and 12" or 14" long, I file very gently the 2 surfaces. This will reveal the high and low spots. On the head, the problem many times is the head is bent from over or under torque on the head bolts. On the block, the problem is usually that the metal around the head bolt threads is pulled up by too much torque.
Use the mill file over the entire block and head surface until the dye is completely removed.
Use a clean up tap to renew all threads in the block.
For torqueing the head bolts, follow the directions in the Honda manual exactly. The only change is that you should tighten them, in the correct order, using 6 or 8 passes and increasing the torque in small increments.
Most people use the "click" type torque wrench. The cheap ones are only accurate to 4%. The good name brand wrenches have accuracy of 3%. The best torque wrench is the old fashioned beam type wrenches with 2% accuracy. These are usually the cheapest too. I don't use any other kind.
The very best solution I have found is all of the above, but using studs instead of bolts. The studs thread into the the block all the way, using every bit the threads. And when you torque the nuts on the studs, you tighten on fine threads and get much more accurate torque readings. The best studs are from ARP, they may have the correct studs, or may not. If you send the measurements and thread size, they will check their inventory and made up stud kits for all engines to see in one has the studs you need. You might be able to get the correct sized sized studs from Taiwan or China.
After you do the first torque on the head bolts, check them after a 10 mile ride. Check them again after 100 miles too.
Aluminum heads on an aluminum block is the most difficult combination to get a good headgasket seal.
All the above information I have learned after 45 years of engine building, with many of those engines being supercharged or turbocharged.
The old Meyer-Drake 4 cylinder racing engines (Offenhauser) had the best solution to head gasket problems - The head and cylinders were one unit. No head gaskets.
"Some Cats Got it, Some Cats Ain't"