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+--- Thread: Crankcase / cylinder head shim (/showthread.php?tid=7098)
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Crankcase / cylinder head shim - Matt_Harnden - 19-01-2022
Hi,
Can anyone suggest a supplier for a shim / spacer between the crankcase and cylinder block. NOT a gasket but a shim/spacer to allow for the cylinder block top to be skimmed.
Thanks.
RE: Crankcase / cylinder head shim - Ruairidh Dunford - 19-01-2022
A7 Components supplied me with a quantity a few years ago.
RE: Crankcase / cylinder head shim - David Cochrane - 19-01-2022
Thanks Ruairidh, but unfortunately I have run out of them and my previous supplier has stopped making them. I have been chasing around to find another supplier but my preferred candidate is being v e r y slow... I will chase him again tomorrow. They will be available in several thicknesses.
RE: Crankcase / cylinder head shim - john williams - 20-01-2022
I have used thick "Hallite" gasket material to make a shim to accomodate skimmed cylinder blocks. The block in question had been fitted with new liners. then dropped, and the front lug broken. Then the base skimmed. It wasn't untill the engine was assembled, and I found the piston was fouling the cylinder head, that we realised we had problem. That was over 25 years ago, the car a "Nippy", is now owned by me and is
still going well.
.
RE: Crankcase / cylinder head shim - flywheel1935 - 20-01-2022
I have a 'small stash' of shims, pm with the thickness you need and I can see if I've got said thickness.
RE: Crankcase / cylinder head shim - Roger - 20-01-2022
This is a spare I made it is 1.5mm (0.060”) thick. You can have.
Roger
RE: Crankcase / cylinder head shim - John Mason - 22-01-2022
If having difficulties getting a shim you could skim the same amount off the top of your pistons to give the same clearance provided it’s not to much.
John Mason.
RE: Crankcase / cylinder head shim - Andy Bennett - 22-01-2022
I have a block which is part of a long term 'when i have time' top end rebuild. It has already been skimmed on the top face (but not the bottom) but by how much I don't know. I am planning on fitting new pistons as a part of the process when pennies allow.
I have gleaned from here suggestions to assemble, turn over with the head 'resting' and then 'feel' the head to see if the pistons are hitting it. Also just putting a flat edge on the block surface to ensure pistons don't protrude. I also appreciate that although a standard engine and so not hitting high revs, there might be some movement in the 2 bearing crank.
So that I know where i am starting from, is there a reliable measurement for a 1930 block height and a generally considered amount that if skimmed doesn't cause a problem? At least then if it is 'obvious' that i will need a shim I can save one assembly process.
thanks
Andy
RE: Crankcase / cylinder head shim - Ruairidh Dunford - 22-01-2022
Roger had to make his shim because two of the rods had not been bored centrally, making them taller when installed, measuring the block would not have revealed that.
Fit the block without any gasket and then install the rods and pistons without rings to check that they all sit below the deck. I think a standard block is 4 3/4" in height - others will know for certain. For a quick chek, if you can still read the valve numbers on the surface it is unlikely to have been skimmed beyond safe use.
Removing material from pistons is tricky and will cause problems for any future replacement, so I personally would avoid
RE: Crankcase / cylinder head shim - Roger - 22-01-2022
Ruairidh,
Yes I did run with those two over length rods, they made no difference to the cylinder pressures which are all good. Before I machined the block it measured 4.8”, I have just checked my three spares they are all the same.
As I said above I now have a spare shim as I made two at the time for some reason!
Roger