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Line boring   

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Its always a challenge to write about something you know very little about. I don’t know whether its line boring, or even “align boring”, but its the cutting of the babbitt main bearings, to fit the crank in the block. This seems to be the  big hangup right now, as the entire restoration is now awaiting this work.

With the Lancia type front and rear seals being threaded metal type (not modern rubber), the alignment of the bearing work (in the block) with the two end fittings (seals) is most critical. It all has to line up.  A few thou difference between the center of the crank at the seal and at the bearings will mean a crank that doesn’t spin….thus the boring fixture has to made to fit not just the four main bearings, but the two seals as well, so that all is on one centerline. And there is little room for error: get it wrong, and it will require new babbitt to be made for the bearings.

The joy of shell bearings in the later cars is that this is not an issue – fit them up, and it should all fit. So the pioneers with the earlier cars have a bit more difficulty here.

I’m told the fittings have finally been made, and that early start at taking boring passes may soon commence. Let others take note: getting all this stuff to line up is very critical, and not so easy. Maybe in Turin there is a machinist who has this all set up, but not here!

Written by Geoff

October 14, 2007 at 12:00 pm

Posted in Aurelia

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