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46 model 18 head/cylinder lapping?

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Gents,

I will soon be in the process of removing head and cylinder on my 46 due to bad head gasket...yes a copper head gasket. PO who rebuilt it used a head gasket instead of lapping...I'm assuming...hopefully it's ok? 

Could someone recommend the the grit# for fine and coarse for me so I don't waist my time and money?

Thanks. 

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Post WW2 the factory used a gasket anyway - probably cheaper - less labour.
Which begs the question: when lapping with coarse and fine, the outer surfaces must have a very small gap.  Do the head bolts close this up?
But if a gasket is used, the gap will be wider (thickness of gasket) unless the machining is different.  So does it close up? If so, is there a danger of breaking something?  Or am I over thinking?  If they machined differently, the later engines wouldn't be suitable for lapping in because of the space for the gasket.

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.. fine paste on the actual head joint, coarse on the outer area. You should end up with a minimal - a couple of thou or so - gap on the outer area ensuring that the head joint is pulled down. I like a very thin coat of wellseal on the outer area to seal the oil drain.

I still have my original tin of valve grinding paste as I never use much.

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I will give it a go on the lapping. The PO used a copper gasket but I don't know the condition yet since I have not pulled apart. The only reason I'm doing this is because when the engine first starts I see/feel air/oil straight out the joint blowing toward the mag. After about 20-45 seconds it's gone and seems to run fine otherwise. 

Am I making a bigger deal out of this than I should? 

 



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