John Deere 4650 Head Gasket

[fordfx413]

I have a 4650 in the shop that was pushing compression in the radiator. Head gasket and head bolts looked like they have been replaced
before. The head gasket was not blown, however when i measured my liner protrusion, a couple sleeves were sitting around .00 maybe slightly
below the block. Machine shop said possibly upper counter bores were cracked. the customer didn't want to overhaul the motor right now so my
machine shop bored the crimped fire rings from the head gasket and gave me steel rings to install instead. Should i spray some cooper coat on
the head gasket when installing as well? I am going to be using new flange head bolts as well. Any input? Thanks!!

 

[Tech 7]

Glad you are using the new bolts, it is pretty much a necessity. As much as the manuals say otherwise I have for years coated both sides of very head gasket for John Deere with a light coat of high tack

 

[Mike M]

Are you placing those shims on top of or under the liner ? I thought you were to shim them up from under the sleeve ? I've never shimmed one though as the few I have worked on the liner protrusion was fine.

 

[tim s]

How many hours/years are on the pistons & liners?? If the head gasket was not blown through your compression into the water system is most likely a pin hole in a liner,,sleeve protrusion is very rarely an issue on these engines..My Vote is to complete the over haul now,,you are wasting time and money if you don't..

 

[Tx Jim]

I agree about it being time for overhaul. I just had my 4255 OH'd due to coolant in crankcase. As it turned out the liners weren't the problem but the liner o-rings had deteriorated. Oh well engine has new P/L & brgs.