Hard To Comprehend But I've Seen It Done

[toobroketoretire]

When I was in my early 20's I actually saw a machinist turn a D9 Cat rod throw .010" under with the crankshaft still in the D9 Cat. Mechanics had removed the oil pan and the machinist rigged up a gear reduction electric motor to slowly turn the crankshaft using a v-belt. He built a fixture that fastened to the oil pan rails and that fixture had a "follower" that fastened to one half of the rod throw while a small grinding wheel ground the other half. Then he re-positioned the fixture to grind the other half of the throw and then he polished the throw. The machinist told me he can also grind the main bearing journals undersize using most of the same fixtures. Amazing, huh? His name was Verle Anderson and he specialized in doing on-the-job-site machining and he was VERY expensive.

 

[kpic]

As under size means adding material and over size means remove material; I believe you "mis-spoke.

If a bore is 1.9375"/49.3175mm. The only way to make it less than is to add material....

 

[kpic]

As under size means adding material and over size means removing material; I believe you "mis-spoke.

If a bore is 1.9375"/49.2175mm. The only way to make it less than is to add material.... At least that has been my experience and as usual, YMMV.

 

[dougelam]

When I was in my early 20's I actually saw a machinist turn a D9 Cat rod throw .010" under with the crankshaft still in the D9 Cat. Mechanics had removed the oil pan and the machinist rigged up a gear reduction electric motor to slowly turn the crankshaft using a v-belt. He built a fixture that fastened to the oil pan rails and that fixture had a "follower" that fastened to one half of the rod throw while a small grinding wheel ground the other half. Then he re-positioned the fixture to grind the other half of the throw and then he polished the throw. The machinist told me he can also grind the main bearing journals undersize using most of the same fixtures. Amazing, huh? His name was Verle Anderson and he specialized in doing on-the-job-site machining and he was VERY expensive.

nothing new, very common in low RPM engines

A lot of racers spin a rod bearing, sand the rod journal and install an over-sized bearing insert

AND win their race

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[Crimson Thunder]

How does this relate to Corvette Tech or performance?

 

[dougelam]

How does this relate to Corvette Tech or performance?

Maybe Verle bought Corvettes with all the $$ he made!

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[Vettehead Mikey]

How does this relate to Corvette Tech or performance?

It doesn't, but most of what he posts doesn't relate to performance, Corvettes- or reality.

 

[Hib Halverson]

As under size means adding material and over size means remove material; I believe you "mis-spoke.

If a bore is 1.9375"/49.3175mm. The only way to make it less than is to add material....

I don't think he's talking about a bore. He's talking about machining a crankshaft journal undersized. To do that you machine the journal smaller.

 

[kpic]

I don't think he's talking about a bore. He's talking about machining a crankshaft journal undersized. To do that you machine the journal smaller.

Hib.
Thanks, that makes sense. I've seen bores knurled make them (kind of) smaller. Turning or grinding an OD smaller is a hat trick.