MTFCA Forum

I looked at a 26 sedan today that a new owner had questions about a knocking noise. This car is a recent purchase of a "full restoration" that had a knocking engine after less than three miles of driving. The number two rod babbit is beat out and I am wondering about cleaning up the crankshaft rod journal. I checked the journal for size and it is standard. Does this rod journal look like it will clean up? I can't feel any scratches and I think what looks dull is babbit material that I will have to clean off. I will check the other rods and check the internal oil tube, maybe the mains. Any suggestions or other advice? Thanks, Art

I have seen something similar to this in an engine that had been run without oil.

You can clean off the babbitt and polish the journal, then carefully check it for roundness, taper, and size. The replacement rod can be fitted for size, if the journal is an off-size, but the the journal must be round and straight. There are a number of reasons why the bearing could have failed.

TXGOAT2 wrote: ↑

Sat Oct 04, 2025 6:00 pm

You can clean off the babbitt and polish the journal, then carefully check it for roundness, taper, and size. The replacement rod can be fitted for size, if the journal is an off-size, but the the journal must be round and straight. There are a number of reasons why the bearing could have failed.

How would you clean and polish the journal? Thanks, Art

"Crocus cloth" is often recommended for polishing crankshaft journals. Something like emery cloth with light oil would probably work OK. I'd use a pocket knife to gently scrape away the smeared babbitt. Scotchbrite might work to remove babbitt.

Sure looks like a run dry bearing to me, being a new rebuild maybe clearance set too tight ?
I'd certainly be pulling every cap to check/verify.

Art Ebeling wrote: ↑

Sat Oct 04, 2025 6:05 pm

TXGOAT2 wrote: ↑

Sat Oct 04, 2025 6:00 pm

You can clean off the babbitt and polish the journal, then carefully check it for roundness, taper, and size. The replacement rod can be fitted for size, if the journal is an off-size, but the the journal must be round and straight. There are a number of reasons why the bearing could have failed.

How would you clean and polish the journal? Thanks, Art

Long strip of fine emery cloth. Work like doing a shoe shine. Will polish about 1/3 @ a time. Rotate crank to several positions for an even polish.

More interesting is WHY did this happen? Normally oil loss takes out #1. Definitely check the inner oil funnel/tube.
You will need to check all the other rods for babbit condition & contact.

Restoration?? Who? Credentials? The corner gas station guy?
The answer to this would help decide whether or not to do a complete teardown. Was this a freak incident or the tip of the iceberg in a poor rebuild? Many more issues to follow? Never be able to trust the T waiting for the next mistake to make itself known.
Talk to the "restorer"

Tight piston? Tight wrist pin? Bent rod? I have yet to purchase a set of rods or remove a set from a motor that didnt have at least 1 bent enough to not need straightening in a set!! TRUST NO ONE.
Sorry to be such a bummer, but I have had to re-rebuild quite a few builds from incompetent T mechanics. Its all in the details.

Daisy Mae wrote: ↑

Sat Oct 04, 2025 6:19 pm

Sure looks like a run dry bearing to me, being a new rebuild maybe clearance set too tight ?
I'd certainly be pulling every cap to check/verify.

Then I would want to look @ the mains.

Pictures #4 & #5 confuse me. Dirt, delamination, dirty piston where the wrist pin is. Doesnt add up.

But, maybe poor lighting? Idk. Im not there.

Question, with everything torqued down tight, could you easily hand crank through all 4 pistons (up/down) or was it too tight?

If no movement from the start, then delamination will occur.
I.e. pop/drag and go and hope for best is probably not the best solution.

If you can fix just the one thing and the other journals/rods look great then i would make sure the new #2 rod/piston/rings/journal rotate freely, fully torqued , without binding (<- a big deal) and try again.

We all learn through mistakes but as others have questioned maybe the rebuild was done by a good intentions person with little experience? It happens. Even if they are an EXPERT problems/mistakes can happen! Don’t ask me how i know…

Tight , is no good.

It is a typical “burnt out bearing”. The babbitt instantly liquifies, slings out, and solidifies. It is usually from too tight clearance OR too little oil (or too much load on the engine). The inside oil line may be plugged or oil level too low. Maybe the babbitt quality is poor, but more than likely it was low oil, plugged oil line, or heavy loading (lugging the engine).

I had a No. 2 rod that looked like that several years ago. A week before the Hamilton tour I tightened up some slightly loose rods, put it together, and had a rod knock at about 30 seconds of running. Maybe I forgot to put my usual "motor honey" on the rod cap on re-assembly. Maybe I adjusted it too tight. But I DID forget to put half a quart of oil in the filler, filling the dips on start-up.