Reply With Quoteto be on the safe side have a machine shop mic it it may only need to be polished but the polishing has to be done on a machine not by hand. its cheap insurance to have it checked by the pros
O.K. Gear Heads,tore down my 468 chev and this is what I'am seeing...On the Bearing surfaces mostly the Rods,some of the Gray Babbet material is polished away leaving shiney metal.There are NO gouges or impregnated metal.As far as the Crank itself,the Main Journals look great,however on some of the Rod Journals, there appear to be some ridges or grooves.Nothing that can be picked with a finger nail,but can (just) be felt with a finger. The Crank (G.M.Cast) was cut to 10/10 some time ago,and fully polished at last rebuild,about 5 years ago.So my question would be...can I buff the Crank with some very fine scotch brite and install new bearings...Or must I have the Crank cut .020 at the Rod journals and fear makeing the Crank weaker? P.S. oil psi was always strong! Thanks HammerDown.
[This message has been edited by HammerDown (edited December 23, 2001).]
to be on the safe side have a machine shop mic it it may only need to be polished but the polishing has to be done on a machine not by hand. its cheap insurance to have it checked by the pros
LIKE tinker said, the only way to know about the crank for sure is to mic it. Your machine shop will know the specs and wear limits. From the way you discribe the bearings, it sounds like normal wear and the crank will most likly be fine to use with out a regrind to .020 . Have it checked and polished, your bearing surface and clearances are not something you want to guess at or assume about.
And I would strongly recommend having the machine shop torque your rod caps on and check the big end of your rods for size and roundness. That is a very critical size that often gets overlooked during a rebuild. Or better yet have ARP rod bolts installed. Your rods will have to be resized if you do, but it will make the rods much more reliable. Good luck
Thanks for the info guys...the rods were reworked with ARP bolts not to long ago.I'll take the Crank to a shop and have it magnafluxed for cracks etc. I'am hopeing not to cut the Crank anymore I'am going to mic. it tonight.It was polished before I hope it will be in spec.after a second polishing!
that could be an indication of dirt from the rebuild also.you could prob get away with the scotch brite.personally if have it down that far and have time you might as well have a machinist look at it or even got to.20 under to be on the safe side.
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