01-08-2018, 08:11 AM
I've now attached the rods and pistons and did a test assemble (no piston rings) but with the base gasket in place and bolted down tight but not with all the nuts in place. I measured the pistons as being 9 thou under the top of the block at TDC. For an engine that you want to rev I seem to remember 20 thou below the block being the safe value? I thought it says in the companion but can't find the page and even though Ian has told me many times before I can't remember the exact amount!
I am using a home made silicone block base gasket and the thickness of that is 0.8mm. Our spares Guru measured one of the ones the local club sells and told me they are about 1.2mm thick. It seems to me I should get one of those and remeasure to see if it gives me the extra clearance I need. I guess the amount of clearance will shrink a little once that's done up really tight and settled.
Rather stupidly I had everything balanced before doing all this so now if I do need to machine anything off the middle two pistons I will need to very carefully make sure the outer two still match in weight.
Once I have the block/pistons sorted I want to check the cam timing again as I can then find TDC much more easily with the pistons in place.
Simon
I am using a home made silicone block base gasket and the thickness of that is 0.8mm. Our spares Guru measured one of the ones the local club sells and told me they are about 1.2mm thick. It seems to me I should get one of those and remeasure to see if it gives me the extra clearance I need. I guess the amount of clearance will shrink a little once that's done up really tight and settled.
Rather stupidly I had everything balanced before doing all this so now if I do need to machine anything off the middle two pistons I will need to very carefully make sure the outer two still match in weight.
Once I have the block/pistons sorted I want to check the cam timing again as I can then find TDC much more easily with the pistons in place.
Simon