Summary

What's the best way to measure piston to valve clearance? OK so we've actually got specific module in this in that cam degreeing course that's about to be released. But my own preference is to use either plasticine or play dough on the top of the piston. I actually go through the process of performing a dummy build of the engine.

00:00 - Paul Hughes has asked, what's the best way to measure piston to valve clearance? OK so we've actually got specific module in this in that cam degreeing course that's about to be released.
00:09 But my own preference is to use either plasticine or play dough on the top of the piston.
00:16 I actually go through the process of performing a dummy build of the engine.
00:20 Dialling my cam or degreeing my cam to where I want it to run, we'll place play dough or plasticine in the crown of the piston, fit the cylinder head, rotate the engine through one full engine cycle and then remove the head.
00:32 And what we can then do is visually inspect the indents left on that play dough or plasticine by the valves when they've opened.
00:40 And you can also cut with a razor blade down through the centre of that plasticine or play dough, and this will allow you to see very very accurately exactly how much clearance you've got down into that valve pocket.
00:52 And in particular this will let you know if you need to make the valve pocked deeper.
00:56 But also you can see how much radial clearance you have and what I mean by this is the clearance between the outside diameter of the valve head and the outside diameter of your valve pocket in the piston crown.
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