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Hi Everyone,

Been doing some engine building today and everything was going great and then I got my first piston/rod slotted in to the bore and attached to the crank. I have the torqued up the crank studs, but have not stretched the rod bolts yet, but they are tight. When I put the engine at top dead centre to look at the deck height, the piston is protruding from the deck. I have not measure it yet, but it looks like about 0.5mm.

At this point I am thinking that the block I am using needs to go in the bin and I should start again. I have another stock bottom end in the garage, so I take a look at that and basically I find the same - about 0.5mm protrusion (not measure accurately).

I realise that the cylinder head gasket will provide some clearance, depending on the thickness.

So my question is, is this normal or are both these blocks scrape?

Thanks in advance for your help.
Si.

Pretty standard for just about every engine Ive put together, excluding Low comp turbo builds like the 8:1 rb25/30 i just did.

Dann

yeah, my B6 was like that. Check carefully but it should be fine once the head gasket is in.

Matty wrote:yeah, my B6 was like that. Check carefully but it should be fine once the head gasket is in.

Thanks Matty - did you measure the height? I have not done that yet, will report back tomorrow what it is.
Si.

Id have to say just about all of the jap 4 bangers Iver ever built have a piston height greater than the deck height by about 0.5 to 1mm.

Dann

Measured the deck height today, it is 0.25mm, so should be all good.

Thanks again for everyone's input, both here in a PMs.
Si.