Just tore down motor after 4,000 miles trying to track down missfire, thinking it was something in the topend. I decided to go ahead and tear down the bottom end too, just to check things out.

I found out that my rod bearings are trashed, wore down to the brass, and looks as though their not chamferred enough for the crank. My main bearings show wear from something going through the bearings, but not the same as my rod bearings.

I'm using the following:

Eagle 4340 forged steel crank (ESP-435334805700 )
Eagle 6" H-beam forged rods (ESP-6000B3D )
Clevite 77 H series bearings

What has everybody else used? Why did the outer edge wear out, and why did the centers wear down to brass in such a short amount of time. Do I have the right bearings, the machine shop that did it says I did.

 

Is it the top 1/2 of the rod bearing? If so it is from detonation.

Check your ring lands on the pistons and check for rings stuck in the lands.

Did you have a dead miss or what?


David

 

Yep, from about 5,000 and up. Top bearing is worse, but both top and bottom are bad.

 

You have the wrong bearing probably.
They don't have the relief/chamfer to accommodates the crank radius.This creates heat from the rubbing.
If the bearings do not fit tight in the rod bore now and seem to be drawn in on the 9-3 o'clock position that is probably detonation especially if the have little "dots" all over the brg but it depends on how much wear is in the bearing to see that.
Did you have the rods resized? If so check the locking tang fit in the rod,it may not have been re done after the sizing.
You may look into the grade/brand of the bearings. Bearings ain't Bearings.
Clevite "H" series or above is the only thing I use.




Any look like this?

 

No resizing, they were brand new, and I did use the Clevitte "H" series bearings, mine don't look like your picture though, I'll see if I can get a picture of them on here.

 

Did you set up oil clearance or just put them in and bolt it together?

1racerdude can tell you how to do it. It took me about 12 hours to do crank and rods. Bearings are not ready to rock and roll out of the box. You get a dial bore gauge in there and will see real quick.

I see so many peopl think stuff is good to go and eat bearings up........If its wearing one sided or anything odd.....when you put that dial bore in it with the bearing in it you will learn alot about bearings.

Have fun setting them up

 

I understand your point on this now, what do you do to correct this though?

 

check everything as it is now....check line bore etc....

once all that is right set up brg. clearances I have been setting them up at .0028-.0030

 

Thanks for the information

 

That's my picture above.

 

Bearing clearances from Callies testing:

Mains: 2.448" Diameter = .0025-.0030"
Rods: 2.100" Diameter = .0025 -.0030"

Bret