Posted this in the Multipla section as that's my usual haunt, but figured I might get more/better advice here.

I've picked up what is (I hope) a bargain recon cylinder head & plan to fit it next month. However, it struck me last night as I was making a list of the bits that I still need to buy, that I don't know what thickness head gasket to use. The head has been skimmed, but I don't know by how much. It is flat.

So: how do I work out the correct thickness of head gasket? I used to use a length of solder pushed through the spark plug hole back in my two stroke days (daze? ) but I'm not sure if that'll work on the JTD - through the injector hole. ePER lists three head gaskets for the JTD 115, in 0.1mm thickness steps, so I figure from this that it's pretty sensitive to set up, but surely it's not THAT sensitive?!

They are usually marked with notches on the edge in one place, the number of notches determines the thickness. It's all to do with piston protrusion, on a diesel the piston comes slightly higher than the block at TDC and the gasket thickness depends on the tolerance and how far the piston comes up. If in doubt, fit the thickest one, I'd defy anyone to feel the difference in performance if it should have a thinner one.