I’ve often said, “It’s a grand experiment". But for an experiment to be valid, one must have repeatable, documentable and verifiable results. Dialing in my valve clearance has been a test of my patience in that regard, and this particular aspect of the engine build has to be spot on.
It goes beyond the cost of the components involved – nobody wants to drop a valve, bend a rod, crunch a piston – but this has become, for me, anyway, a test of my ability to build a genuine, no compromise, no excuses, single purpose racing engine. Given the enormous aero disadvantage of this car, and the restrictions that competing in a production category places on what I can do to improve the body, my only prayer of making it work pivots primarily on maximizing this engine.
After trying 3 different methods to correctly suss out precisely how much valve clearance I have, I’m delighted to report – plenty.
I tried measuring with testing springs and the valves in place with feeler gauges, the valves in place with a dial indicator, and with the testing springs removed and checking clearance with the valve riding on top of the piston with feeler gauges (verticle valves). All of these methods gave me wildly differing results.
So I called my dad on Thursday – before he went into purchasing at Rockwell, he was a parts inspector for Collins Radio. Collins had the NASA communications contract during the heyday of Apollo, and it’s my understanding that there are parts he’s handled that are still sitting on the moon. If it can be measured, he knows how to do it, or who to ask.
He contacted an old family friend, Ray Burke, who I understand builds off road racing trucks, and has a lot more hands-on experience than I do. Incidentally, my first racing experience, the Soap Box Derby, included axle trees with channels cut by Ray.
“Go with clay” was the response – which was, of course, the consensus of most of you – McRat, wil6er, Gwillard, specifically.
I mentioned repeatability – I did it twice. Bear in mind, I’ve got a .029 Cometic headgasket sitting downstairs – which I WILL be able to use . . .
.060 on the intake side, .100+ on the exhaust.
I’ll be buttoning this one up tomorrow, boys and girls.
K I S S.