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
 
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.
 
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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
 
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.
 
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 ?
 
Rich Bowes said:
How often should crankshaft bearings be checked. I have heard every 5000 miles. Is that correct?
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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.
 
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?
 
And make sure you do them with the engine still in the car, laying on your back without a hoist. It builds character.....
 
Rich Bowes said:
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?
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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.
 
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