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Pounded rod bearings and main caps walking on fresh motor

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beansblacktsi

15+ Year Contributor
283
53
Apr 2, 2007
Lincoln, Nebraska
Well I had my local machine shop build a 6bolt for me. It is just a standard Wiseco/Eagle setup, stock crank, and ill have to check what bearings were used. They did all the machine work and assembly of the rotating assembly along with balancing the motor. I installed it and broke it in just as stated by them and changed oil after the 100 mile break in. Then I started turning up the boost and tuning afrs. I ran out of injector at 30psi so I stopped there and max timing was around 18 degrees. I will post logs a little later today.

In total I have 515 miles on the motor and about 300 of those mile are highway miles from driving to and from the track in which I made two low ten second passes. The other 200 or so miles it was dd'd and beat on.

I changed oil again at the 500 mile mark which is what they told me to do and it was full of bearing material. So I pulled the motor and had them check it all out. It ended up being the number 2 and 3 rod bearings were pounded really bad. He said from an really aggressive tune and high timing. Also he said the mains were walking pretty good also from to much timing.

Now this just doesn't make sense to me because Im using the same timing map that I used on my 150,000+ mile stock motor that saw the same abuse for 2+ years of 100 percent abuse until a stock rod bolt finally let go. I had even more timing in that motor up top than this one.

So I guess what I am asking is does what he is saying make sense? I just cant see that much damage happening in that little amount of time. Does anybody else have any theory's or things to check or ask the machinist? Like I said ill figure out what bearings were used and post some logs and my tune later today when I get home from work.
 
Posting pictures of the bearings would probably be the most help.
 
There is a lot that could be explained but it probably will not be.

What were the main and rod bearing clearances set too?
What bearings were used?
Do the plugs or the top of the pistons show any signs of detonation?
What half of the bearings were beat up?

On an aggressive tune with knock you should see the top rod bearing beat to crap and the bottom main bearings beat to crap.

If there evenly worn all the way around then it could have been a clearance issue that I doubt the machine shop is going to take blame for.


Did you check the machine shops work before you installed the engine in the car?

What oil was used for break in and final fill?
 
You ran quite a bit of timing for a low 10 sec pass. Its all about where the wear on the bearing is. If it is the top bearing with the most wear it is too much timing. Also if they notices the main walking you would want to know how much press is present for the main caps. Make sure you run a good bearing with adequate clearance for the oil to do its job.
 
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