Bearing wear

[JVMopar]

Took my race 318 apart today to inspect the bearings. They are worn threw to the copper in a groove by the edge of the bearing. More than one cylinder was like this but not all of them. What would cause wear like this? Just dirt?

The bearings have 7 races on them. The inside of the engine was very black. When I assembled it I had everything apart and washed with soap and water the best I could.

[Ray Bell]

Lubrication... in short, just lubrication...

Whether it's the type of oil, surge causing loss of pressure, simple inadequate pressure or whatever, the oil just isn't getting in there well enough to keep the surfaces apart.

[DartGT66]

Seems to me more like tapred crank journals? Do you have a radiused crank there? Looks just like the bearings do not clear the radius in the outer edges?

[Ray Bell]

Good point...

How many are like this and is there a pattern to where they came from?

[JVMopar]

Stock cast crank, so there is no radius (actually a bit of a groove there). The original bearings that came out of it didn't have wear marks like this.

There were 3 or 4 rod bearings that were like this.

The main bearings are aluminum and weren't worn too bad, but had a rough feel like dirt contamination.

The whole inside of the engine is black with a good layer of crusty carbon on it. I'm wondering if it's comming loose and going through the oiling system.

What was left in the bottom of the oil pan looks like mud, and it was clean when I put it back together.

[JVMopar]

Sitting here stairing at this bearing, I'm thinking it's oil starvation and dirt combined. You can see there is alot of particles imbeded in the bearing, but if you look closely at the side that's worn to the copper you can see the babbit is pushed up to the parting line of the bearing.

The oil pressure was rather low on the last race. That's why I wanted to check the bearings.

[Ray Bell]

Time to check the oil filter and pump, methinks...

[adodgemann]

Did ya have a circle track pan on it ??? Kevco makes them, cheep insurance. Running a stock pan on our pure stock we couldn't keep bearings in it, even with 7 quarts of oil...

[cudabob496]

Originally Posted by JVMopar

Sitting here stairing at this bearing, I'm thinking it's oil starvation and dirt combined. You can see there is alot of particles imbeded in the bearing, but if you look closely at the side that's worn to the copper you can see the babbit is pushed up to the parting line of the bearing.

The oil pressure was rather low on the last race. That's why I wanted to check the bearings.

Do you use synthetic oil? Wonder if it would make a difference?

[JVMopar]

Just a stock pan. Going to a Kevco this year. Since I now have a job and some money to spend. Just the wear pattern on the bearing has me baffled. You'd think it would have wiped the bearing out more evenly. I'm going to do some oiling system upgrades and have the block hot tanked.

Was using Mobil 1 15-50 was on sale $20 for 5 qts. I put 6 quarts into it.

[cudabob496]

Originally Posted by JVMopar

Just a stock pan. Going to a Kevco this year. Since I now have a job and some money to spend. Just the wear pattern on the bearing has me baffled. You'd think it would have wiped the bearing out more evenly. I'm going to do some oiling system upgrades and have the block hot tanked.

Was using Mobil 1 15-50 was on sale $20 for 5 qts. I put 6 quarts into it.

wonder if there would be a diff in wear pattern had Mobile 1 5-30 been used?
Maybe depend on how tight the clearences are?

[cudabob496]

Had a cirlce track racer friend who put in a system that brought oil pressure up before starting. At end of season, no observed bearing wear!

[Ray Bell]

Originally posted by JVMopar
.....Was using Mobil 1 15-50 was on sale $20 for 5 qts. I put 6 quarts into it.

Could you possibly have experienced frothing of the oil?

This happens when the pan is overfilled and the rods start dipping into the oil and beat it up like a milkshake, eventually the pan is full of froth and you pump gobs of air through the oil pump instead of straight oil.

[lilcuda]

Originally Posted by JVMopar

The inside of the engine was very black.

If the inside of the engine is very black after only 7 races, it's either running too rich, or your rings never seated properly and you had lots of blow-by. That can wear the bearings out.

Take the crank, pistons & rods & block to a good machinist and have everything measured, then go from there.

[ehostler]

I agree. You need to figure out why the engine is black after 7 races. It's probably killed the detergents and lubricants in the oil. Any of it that is circulating is probably rather abrasive as well.

[JVMopar]

It was a used engine that I slapped together. After 30 years of neglect there is quite a bit of crud built up.

I was drilling out oil passages this weekend and the ones that were already 1/2 inch had thick black crud built up inside them. I'm sure moving a high volume of oil along with heat was causing it to come free.

I've got it all apart and degreased. It's going up to be hot tanked tomorrow morning. It will be spotless before it goes back together.

[cudabob496]

Choice of oil filter could also be a factor, as far as what size particles it will allow to pass.