#2 Rod Bearing Failure

[Fergie76]

My engine has lost the #2 rod bearing 3 times. Each time it has gouged the crank and it has been replaced 3 times as well in less than 15,000 miles. The oil pump was replaced with a new shimmed asian oil pump the casting was machined to the minium specifications. Runs rich by the plugs. All factory electronics. Boost at about 6 lbs with a worn wastegate spring. I cant figure out what is causing this rod to keep failing. Has anyone out there had problems with the #2 rod bearings. I have run calico coated NDC bearings all 3 times.

 

[Maple191]

Are you saying you replaced your crank 3 times or just the bearings?

 

[GrimJack]

Stop and think about it... if it's not the bearings, what else could be the problem?

How does oil get to the bearing?

Have you checked the clearance with plastigauge?

 

[Fergie76]

Yes the crank was replaced 3 times. I did not want to use non-standard bearings

Plasti-gauge was well within factory specs.

The only common denominator is the block but I don't understand how this could effect only 1 rod. From the looks of things #2 was oil starved. All the others simply have some minor scoring from the bearing coming apart. I don't understand why #2 is different.

 

[IndigoMKII]

Yes the crank was replaced 3 times. I did not want to use non-standard bearings

Plasti-gauge was well within factory specs.

The only common denominator is the block but I don't understand how this could effect only 1 rod. From the looks of things #2 was oil starved. All the others simply have some minor scoring from the bearing coming apart. I don't understand why #2 is different.

Have you tried checking the oiling ports inside the block to make sure they're not plugged?

 

[Supraguy7M]

All I can think of is the oil galley in the block is probably plugged, or obstucted reducing oil flow. I'd have the block looked at personally. I don't know exactly how the oil system works In the 7m. If it continues being starved after you've done everything right, I would think its the block

 

[Prism11]

Check the bore on the #2 main cap. If the bearing spun it probably wiped the cap out. The bearing clearance most likely is not consistent the entire diameter.

 

[Nick M]

The only common denominator is the block but I don't understand how this could effect only 1 rod.

Sounds kind of like a select fit bearing issue.

 

[jake8790]

Were the rods resized?

 

[QWIKSTRIKE]

Were the rods resized?

Resizing the rods and having the crank journals done all at the same time is necessary. The rest lies in using the proper oil and excellent assembly skills. Poor tuning will also cause rod knock from detonation.