Rod journal diameter?

[rb68rr]

My crank is turned .020. When I put a micrometer on the rod journals it measured 2.226. Is this correct? Lost oil pressure and the bearings went away, however the crank still looks ok. Thanks, R.B.

 

[TurboDave]

Well, the factory spec for the crank pin journal is 2.2487 - 2.2495. So..... With your 2.226 measurement the difference would be .0227 on the small side and .0235 on the larger side. That leaves you with some pretty hefty clearances!
How can the crank be "OK" with the bearings tore up?

 

[rb68rr]

Since the crank has been turned .020 wouldnt you have to add that back to your figures? When i said it looked good, I mean't to my eye. Couldn't feel any grooves with my fingernail!

 

[TurboDave]

What I was trying to say is, your rod journals are already between 22.7 thousandths to 23.5 thousandths under. depending on what side of the tolerance you want to use. On average you're down 23.1 thousandths.

 

[rb68rr]

I need another crankshaft, huh?

 

[TurboDave]

Hard to say. I haven't seen it, or measured it. And you would want to measure the rod ends with new bearings to see what kind of clearances you'd have with this one. A good machinist can tell you what you need to do.

 

[FASTV6HENRY]

IT LOOKS LIKE YOUR CRANK MAY HAVE BEEN TURNED .020 ALREADY. OR YOUR MACHINE SHOP DIDNT MEASURE IT BEFORE MAKING THE CUT. HOWEVER, I WOULD DO WHAT TURBODAVE SAID AND TAKE IT TO A "GOOD" MACHINE SHOP AND GET IT CHECKED AGAIN NOT SURE IF RUNNING .040 OVERSIZED BEARINGS WOULD BE A GOOD OPTION.

 

[TurboDave]

IT LOOKS LIKE YOUR CRANK MAY HAVE BEEN TURNED .020 ALREADY. OR YOUR MACHINE SHOP DIDNT MEASURE IT BEFORE MAKING THE CUT. HOWEVER, I WOULD DO WHAT TURBODAVE SAID AND TAKE IT TO A "GOOD" MACHINE SHOP AND GET IT CHECKED AGAIN NOT SURE IF RUNNING .040 OVERSIZED BEARINGS WOULD BE A GOOD OPTION.

Yes, he stated in his original post that the crank was turned 20 under. My posts merely confirmed this, it appears to have been turned 20 under plus a little more. That little more was my concern.
Gotta find someone that can measure all the journals to the nearest 10 thou.

And I would not turn it again. More than 20 is IMHO excessive.