Rod Journals out of round

[Jbird988]

Have a crank here which all the rod journals are .0005 out of round on a fresh grind and cranks are hard to come by for this engine. Must be something is up with the grinder used or maybe to much pressure on the steady rest?? It is ground .030 under even though it was supposed to had been .020 and its even stamped as .020. .040 undersize bearings for this engine are on a back order until may. I'm also wondering how far off the stroke lengths on this crank are now. Factory spec is 2 tenths out of round. How bad of a idea is it to put this crank into service? Probably localized stress on oil film and bearings? A change in load capacity obviously.

[BillK]

What does the guy that ground it say ?? I would not be real happy with it. What engine ?

[Jbird988]

What does the guy that ground it say ?? I would not be real happy with it. What engine ?

I'm not even going to bother with the guy that ground it. I've confronted him before on stuff and he will just say things like it was that way from factory as well or worse from factory so it's fine the way it is now. If i was someone that didnt know any better this crank could have been put together with .020 undersize bearings because that's what the crank is marked as but really he took .030 off. Went against my better judgment and had him grind this crank because otherwise I got to take a 8hr round trip just to drop something off from where I live if its something I'm not equipped to do. The engine is a toyota 3rzfe, everything specs pretty tight on these things. I've been on a long road of getting previously machined parts corrected on this thing.

[Geoff2]

You can get it hard chromed & re-ground to size. Expensive, but if is rare....

[mag2555]

From what I just sniffed out in my FM bearing book there is a .0005” tolerance that is allowed.

If the journal (s) are out of round by more then that .0005” and the crank is straight, then yes that’s a issue!

Not to be a wise ass, but you do realize that for example a cut of .010” removed takes a .020” under bearing and so on with more removed, right?

[Dan Timberlake]

Clevite and others say something about like this -

Out-of-Round:
.0005” (.013mm) maximum up to 5.000” (125mm) journal
.0002”-.005mm for HD or highly loaded engines
(Never use a maximum out-of-round journal with a
maximum out-of-round bore.)

[Jbird988]

From what I just sniffed out in my FM bearing book there is a .0005” tolerance that is allowed.

If the journal (s) are out of round by more then that .0005” and the crank is straight, then yes that’s a issue!

Not to be a wise ass, but you do realize that for example a cut of .010” removed takes a .020” under bearing and so on with more removed, right?

I had seen the .0005 mentioned as well from a few bearing suppliers. Crank is straight, I was able to indicate that myself. Really sucks having it be at max out of round according to bearing suppliers and toyota says 2 tenths so wasn't sure what the consensus would be on this situation. In regards to the journal sizes .030 really was removed from the journal when it should have been .020.

[BillK]

In regards to the journal sizes .030 really was removed from the journal when it should have been .020.

Then I have to wonder if he did that correctly ? Most import bearings are in mm sizes so that should be .75mm which is really .0295"

[MotionMachine]

No way that .0005' on a journal that small is acceptable. And that's what you can measure with a mic. I guarantee you'd find more than that if you were to put the crank back in the grinder and run the Arnold gage on it.