Update: Clay test and Measuring Valve MOP
Posted: Mon Oct 09, 2017 11:44 pm
Since the head has been skimmed many times before, the machine shop expressed some concern that I might need an oversized head gasket to maintain adequate separation between the pistons and the valves. I decided to do a clay test in the spirit of other posts on this forum, to see for myself.
After filling the valve pockets with modelling clay, I built the head back with the old headgasket, which i believe to be a standard thickness. Much faffing later, I managed to jimmy the cam sprockets back into position, with the timing marks more or less where they should be. After a couple of full rotations, and without any binding (thankfully), I removed the head and found that only the intake valves had made an impression on the clay (as per photo). Using a sharp knife, I chopped the clay in half, and found a clearance of about 150thou. This seems plenty (I recall 60thou as a minimum), so this is good news i guess?
I'd like to make sure the engine is timed correctly. I know this is a well covered topic but I did have a quick question for the wise among us. Using a dial gauge, I've accurately determined where TDC is. But how do I use the dial guage to measure the point of maximum valve lift? There doesnt seem to be much space between the cam lobe and shim to poke it in there... Any help much appeciated .
This engine, despite its pitfalls and money draining abilities, is proving to be a great learning experience for an amature such as myself!!!
Best
Dave