Thread: Bearing failure. What caused this? (pics inside)

No as long as you used assembly lube it shouldnt have affected it. If its just that one bearing that failed it was more than likely a definite cause from overtorquing the rod bolts. Instantly will out of round the rod and cause that issue very early on.

You will have to purchase a new rod for sure if thats the case.

Yeah doesnt look like thrust washer. Its a big chunk of the bearing which means the bearing is most likely completely gone from between the rod and crank. And either way that bad of knock would cause the rod to go even more out of round. Dont bother even trying to reuse it. Not worth the risk. Replace it and try again.

Overtorquing is the enemy. If they are the 3/8" ARP2000 rod bolts torque to 43 ft-lbs using their supplied lube and be done. Simple as that.

Oh dang Doctor G didn't you just install an oil cooler?

Here is a link to manley's instructions the sr20 uses a 1.5" arp bolt.

http://www.manleyperformance.com/dl/tech/rod-hbeam.pdf

lost oil pressure, or material from previous issue caused this failure as well.

Any history on the engine? Sometimes spinning a rod bearing can cause issues in future builds unless you are absolutely meticulous about getting all old bearing material out.

This motor fresh? why was it rebuilt?

hey guys,

so pulled the motor out today. It is in fact no 3 rod thats the main culprit. I can move it up and down a lot - as if there is almost no bearing in there. The rod cap also looks kinda blue-ish now from the heat. Almost like a titatnium tipped exhaust muffler. Guess it got very hot!

No one rod can also move around a little, as can number 4. No 2 is solid. As I mentioned the bearing failure occured on the freeway in peak traffic so I had no choice but to lug it home - which inevitably caused more damage. I haven't pulled the bearing caps or the main caps yet. Want to have an engine builder present when that's done so they can give an opinion on the cause.

The motor was built initially with 16ve pistons, at which stage I did the knife edged crank as well. Ran well but eventually ran a bearing. I can't recall which one but I think it might have been no 3.
Then I switched to CP pistons and manley rods and kept the crank. Drove untunedt o the dyno and blew the headgasket. Car overheated.
New headgasket. Overheated again. Block seemed out of round.
Installed a new block. Had the crank machined and went a size bigger on the bearings. Ran fine for 2000kms incl. running in. Recently installed the oil cooler and oil pressure hardly dropped. Maybe half a bar if that much.

Had one race against an E46 M3 with a few mods - which I beat btw. Then I notcied oil pressure was maybe another half bar lower from that day onwards. On cold start, warm up, idle, everywhere, half a bar lower than before. The next two days the motor sounded a bit rought on start up, almost like the old style DE chain tensioner. And eventually after one redline pull on the highway i got the death rattle and the oil pressure ligth come on.

I am in 2 minds about rebuilding this engine again. Especially if you guys say I'll need a new rod. Does manley even sell individual rods??

So new rods, new bearings, new crank (got spare DE untouched cranks available), engineering on the 3 good rods. Possible line bore on the block for the mains, new headgasket, new oil pump. Also, if I apply some pressure I can kind of move the pistons a fraction in their bore on the cylinders with the damaged rod bearings. Is this normal and due to the bearing failure or is there something wrong with my pistons?

For less money I can have a perfectly good Avenir motor, boost pipes and fmic. Confused.


here's some pics. Compare the colour of no 3 rod on the left to number 2 on the right.




And the two pics below show how far the rod can move up and down on the crank. I'm pretty sure the bearing is not present at all anymore.

just buy new rods. start with a different block. looks like most of the engine is trashed in one way or another. also check the cam bearings up top. if it ran with low oil pressure it can damage those too.

You don't have to replace the rod. The rods change color at a pretty low temp and you have to get heat over 800*F to take the heat treat out, the discoloration is supposedly from the nickle in the steel they use that causes that. But it happens pretty soon.

All 4 of my rod big ends are black. I was concerned I had to replace them and fork out big bucks. Instead, I called the manufacturer and talked to their engineers (at Pauter) and they said if they didn't warp I should be fine.

So we checked them for straightness, and they were still good. We cut the caps down and re-honed them slightly and it was all good.

These rods have done awesome for the last 3 years, even revving out to 8800rpm and 450+whp. Even with a specialized "anodized coating"!

CAM BEARINGS...

YOU FAIL... nuff said. There are no cam bearings in any SR20 engine.

Theres a cam bearings. Gotta run it tight tolerance kinda like cory. Ask him he'll tell yalll lol.

I dare say its an assembly related failure.

Oil starvation, poor preperation and incorrect sizing are the first things that come to mind for me.