More Gremlins pay a visit..

Several car friends had been curious regarding the power potential of the little 6 cylinder Chevy and I contacted them after the dyno run to share the hp numbers.  141 seemed acceptable to everyone with one comment being made that Chevy was known to over rate their hp numbers back then so the 115 number was probably high.  Nevertheless, something kept knawing at me that 141 was too low.  Shoulda been more.  I stayed real busy with computer repairs for a couple of weeks and couldn't make it back to More Power right away.  I talked to Dick on the phone and told him I wanted to run a leak down test on the motor just to be sure some other issues didn't exist.  I finally got a break from the computer biz and made it back to More Power. 

The leak down test started off just fine.  The first 2 cylinders checked at about 12% leakage which I felt was acceptable.  My drag racing engines had checked at 4 - 8% leakage back in the 70's so 12% didn't seem too bad.  Then I checked the 3rd cylinder - 65% leakage!  I couldn't believe what I was seeing on the pressure guage.  Duane came over and double checked my work.  He even gave the valve springs a tap to make sure the valves were seated.  The valves were sealed up rock solid.  The entire pressure loss was blowing straight in the oil pan!!  The final 3 cylinders had one at 12% and the other 2 in the 65-68% range.  My heart sank.  This meant the entire engine had to come apart again to find and fix the problem.  The rings were obviously not sealing but why?  We had chosen Hastings cast, stock replacement rings for this build.  I had checked the ring end gap on #1 cylinder for the top and 2nd ring prior to assembly and found the gap to be about .020" so I hadn't bothered to check the other 5 cylinders.  In my old drag racing days, I would buy rings that were .005" oversized and cut the end gap to my desired dimension.  The Hastings rings were loose enough that no cutting was necessary.  As I was removing the rings from the pistons, I noticed that some were easier to expand with the ring expander than others.  When I lay the rings side by side, I was shocked at the what I saw. 

Not only were the rings varied in diameter, you could see where only part of the ring surface was contacting the cylinder wall.  Further inspection of the bearings showed contaminants in the bearing surface, either from the ring wear or the water contamination - or both.  The main and rod bearing journals were scratched on the crankshaft too.  Now, we REALLY were back to square one.  I cleaned up the parts; the crank went out for grinding; Dick ordered all new parts (bearings, gaskets and Sealed Power chrome rings); Duane rechecked the bores on the block and did a touch up with the hone; and I took a 6 day vacation in Florida with my wife.  Hopefully, we had identified and eliminated all the gremlins.