Crank shaft bearings
 

How often should crankshaft bearings be checked. I have heard every 5000 miles. Is that correct?

Re: Crank shaft bearings
 

Depends on different items such as the quality of babbitt used, whether it was peened in, and/or how much surface coverage the babbitt has to the journal pin.

Re: Crank shaft bearings
 

I make the first check at 5000 miles, if very little wear I let them go another 1000 miles or so on the second check, if excessive wear is found I check sooner the second time, around 3000 miles, like brent said, it depends on the babbit, how it was installed, who did the work, how car is driven and maintained

Re: Crank shaft bearings
 

I've checked and adjusted the original babbit in my september 29 three times in 54 years .

Re: Crank shaft bearings
 

The engine in mine was done in 1961 and I tightened the mains a couple years ago[ the center and rear needed it], the rods were fine.


I guess I should add that I've done a few others over the years, I don't know the number of years or miles on them.
Only one needed the rods taken up a bit. All have needed a little help with the center and rear mains, nothing to the front.

Re: Crank shaft bearings
 

I checked the main bearings once in 50,000 miles, and they were 0.002 to 0.004.

Re: Crank shaft bearings
 

Goodness! if one checked the main bearings every 5000 miles, for some us, that could be twice a year.
I drove my first Model A as daily transport and hard for a number of years without ever checking the mains and without any problems.
Keith

Re: Crank shaft bearings
 

My Lord! If it's runnin' well & sounds good, leave the danged thing ALONE!!!
You'll wear out all the FASTENERS, just dickin' around with it.
Bill W.

Re: Crank shaft bearings
 

Right, that's what wears out pants zippers.:D:p

Re: Crank shaft bearings
 

Well, I was going to give some sort of great insight, but I can't top Bill and Tom.

Re: Crank shaft bearings
 

I thought for sure we would have gotten some comments from our residence engine rebuilders. What would their recommendations be on the subject to their customers after having their engine rebuilt ?

Re: Crank shaft bearings
 

When it is needed. There really is no answer to this question. Depends on how good the Babbitt was done how good the bearings were set. How fast you drive, plus a lot more.

I would just pay attention to the sounds of the engine when it is under load. If it knocks under load you may have a loose main. Also when you first start it after it has been setting for a while. The center main will knock when you first start it, on tell it gets oil if it is loose.

If you have to take the pan off for some reason, or you have a bad rear main leak check them then.

Re: Crank shaft bearings
 

As some of you have suggested, the correct answer is: "if it ain't broke, don't fix it", or "don't go looking for trouble unless it comes knocking". Do I have this about right?

Re: Crank shaft bearings
 

And make sure you do them with the engine still in the car, laying on your back without a hoist. It builds character.....

Re: Crank shaft bearings
 

Oh man, and is that why sailors had buttons on their pants instead of zippers:eek: Not sure about today.............

Re: Crank shaft bearings
 

It may be smooth and quiet with no load and not rear its ugly head until put under a load. Then it can be hard to hear but may be felt. Main bearing that is.
If it seems OK, it probably is. If for reason the pan ever comes off, then is a good time to check them.