Machining a crank shaft, anyone know of good engineer to do this? Turangi - Auckland

[Hamish Carlson]

Ages ago I had a thread about my gsx400 crapping out. Still sad, and still in parts. Found one guy in rotorua that could machine down the big end journal, and take the bearing, file down where it bolts together and hone the inside round again for $460. This seems unbelievably expensive and after talking to a bloke up in whangarei - very stupid and short sighted to even think about grinding down a bearing shell instead of replacing it. BUT ANYWAY, what needs to be done: 1 crank journal built up and machined down, the other one machined to the same undersize. Also what other bearings would be needing to be replaced? Oil pump is fine, so any clues what could cause the big end to fail, just out of interest? Also if there's anyone in rotorua/taupo area with a bit of know how about putting an engine back together, I can pay for time in beer.

[brockzila]

any engine reco shop that has been around for a while should be able to do it.
but i would use murry Papakura engine specs
ewan mcewan auckland engine reco
west auckland engine reco
and glen at tepuke i think.
glendene eng. reco.
i delt these guys on a dayley bassis when i was selling engine parts.
there are cowboys out there and some not bad guys. but these are the ones i trust.

[Woodman]

i don't think he is talking about grinding the bearing shell down, but the con rod. It is known as resizing where you machine a wee bit off the mating faces of the bearing cap and the con rod, bolt them together and then machine or grind the inside so it is round again and to the correct size so the bearing will have its correct amount of crush etc. The crank grind is a fairly basic operation for any reconditioner with a crank grinder. It can get more complex these days as a lot of cranks are hardened and often will need re hardening (nitriling) after the crank is reground.

[CookMySock]

Cant they just grind the crank and then use oversize bearing shells?

Steve