Any Crankshaft Techs out there?

[michelle g]

Help desperately needed.

We are the owners of a Pontiac Transport MPV 3.1L 1990
here in Spain and the crankshaft has gone off for a
regrind .

The problem that we are encountering is that we have
to buy bearings for the machine shop to grind down to
as its very difficult get the bearings for an american car in Spain.

We cannot order bearings from another country without knowing what size to order and we are getting very confused with this as no one
can help us.

Our main bearings are currently 0.016 US and that part of the crank just needs a polish (would we get away with 0.10US?)

Our other bearings are standard but this part of the crank needs to be taken down to 50mm /50.1mm or 50.15mm (this needs to be converted into inches for the bearings )to take out an
ovalling on the crank. (would this be 0.10US or
0.20US?)

Anyone out there know the specs etc that we need cos the cars been off the road now for 3 months and its desperately needed in the next two weeks and frankly im starting to crack lol

Thanks to anyone who replies .

michelle

[cdru]

Whenever you have a part worked on, such as machining, grinding, polishing, etc, you are changing the specs of that part. At the factory, those parts have a fairly precise tollerence and require a specific bearing size. When you have your crank reground, you are reducing that diameter ever so slightly. As a result, you may need to go with a slightly larger (or oversized) bearing to help take up that space. If you were to go with the original size when you need oversized, or vice versa needing the factory spec size when you used oversized, in a whole host of problems may result.

Your machine shop or automotive shop doing the work should be able to tell you exactly what size you need to order. If they can't, find another shop that will. You can also do it yourself using something like a Plastigauge. Plastiguage (or the equivilent) is available, at least around here, at most autopart stores.

And by the way, while the we in the US still is stuck using the imperial system for measuring things, many autoparts are speced out using metric. There isn't a need to convert bearing sizes to inches...keep them in metric as that is what you will be using to order new ones in this case.