Lapping Head to liner/muff

Martyn Goodwin

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Non-VOC Member
Will soon have my head back from rebuild with valve seals etc. What is the technique to be used to lap the head to the liner/muff?

Are there any traps for new chums like me to be aware of?
 

chankly bore

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Richardson page 44. Avoid side thrust.At least 75% contact on outer surface-more is better, and 100% contact on inner face.Absolutely clean afterwards.Coarse paste outer, fine paste inner. While you've got it apart put a LITTLE bit of gasket sealant on the upper part of the ET55/2's thread into the crankcase if you can partially unscrew them; particularly the timing side rear one. Prove the oil feed to the rear of the piston from the timing cover and check that the oil feed hits the piston below the oil ring at BDC. By the way, valve guides must be reamed with a pilot fitting a modified-i.e. 3/8" nominal i.d. upper valve guide.
 

Martyn Goodwin

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Thanks for the extra information Charlie. Mine is a first edition of Richardson that does not include this detail.
 

timetraveller

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VOC Member
I always find it easier to hold the cylinder head, combustion chamber facing upwards, in a vice with soft jaws and then rotate the barrel by hand. This ensures that at least one part is held securely and it makes it easier to try to keep even pressure on the joint.
 

mercurycrest

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VOC Member
Before you get the parts back, why not have the shop/rebuilder do a proper job with a milling machine? .003 clearance.
Cheers, John
 
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