proper diagnostic process for RB?

[BeaterM3]

Originally Posted by BimmerRules!

Dang! sorry to read that. Hope you caught it and fixed it before bigger issues.

Bunch of queries pls:

Which year was your car? How many miles were on it? And how did you know - that too within a month - that the RB's were nearing failure?

i got the bearings done 2 weeks ago. I only had the car for a month at that point and decided to only drive it for a couple hours before parking it until getting it to the shop for the replacements. There was no failure but the bearings were very worn.

Mine is a 2010 with just under 82K. I didn't know they were very worn. I just didn't want to roll the dice and chance it. I had to get the oil pan for the DCT fixed, so I was like fuck it, I can do the bearings as well (motor mounts were done too).

The way I saw it ... I only spent $17,500 on the car...another $2,800 for the rod bearings/motor mounts and DCT fix was a good investment.

[CHE///MIST3]

Wow, you got to those bearings very quickly after posting! Good work. I do hope your crank is ok so you can just put new bearings in and keep going. Make sure to keep those bottom ends of the conrods in order as they were taken out so they align properly when re-installing.

GM

[Drifter2090]

Ahhh this makes me scared to drive mine now! I have perfect oil analysis' also

[CHE///MIST3]

Originally Posted by Drifter2090

Ahhh this makes me scared to drive mine now! I have perfect oil analysis' also

In my previous M3 one oil report had a reading of 19 ppm lead and Blackstone would say "it could just be a particle streak" then it would drop to 6 the next time, and so forth. A roller coaster of emotions All we can do is let the car warm up while driving and have some degree of mechanical sympathy until it's time to swap the bearings.

GM

[///M Power-Belgium]

Originally Posted by tweny

will snap a better pic when I can.

Your bearings really look bad . I'm 100% sure there is a lot of debris in your oil system .
I wish you the best of luck . Please keep us posted as for updates regarding your situation ...

[///M Power-Belgium]

Originally Posted by pbonsalb

M3 Belgium has listened to audio of a lot of cars. Record yours and send it to him.

Spot on !

[tweny]

decided to fix the car earlier than I expected. took apart the oil pan today and checked the crank for any damage. turned out to be intact. got really lucky with this one. will be replacing bearings and bolts with OEM. when I put 50k miles on them, I'll change them to BE bearings and ARP bolts.

[tweny]

quick pic I took before I left. will picture all the worn out bearing set when I go back.

[tdott]

Goodluck, if you were hearing rod knock there has to be damage to the rod and/or crank. That won't go away with new bearings.

[tdott]

Originally Posted by tweny

will snap a better pic when I can.

Hopefully you are keeping track of which rod end cap goes where, or atleast match up the numbers to make sure they go before you torque those rod bolts.
That picture of two rod ends just thrown about in a pool of oil, does not inspire confidence.

These are fractured rods and are not interchangeable, must go back in exactly the same position.

[Scharbag]

Originally Posted by tweny

decided to fix the car earlier than I expected. took apart the oil pan today and checked the crank for any damage. turned out to be intact. got really lucky with this one. will be replacing bearings and bolts with OEM. when I put 50k miles on them, I'll change them to BE bearings and ARP bolts.

I will never understand the reasoning behind using a new set of OE bearings when extra clearance bearings are available from ACL, VAC and BE. Especially when you follow it up with "I'll change the to BE bearings and ARP bolts" in the very next sentence. What logic are you using to make this choice?

Good luck and I hope your engine is ok.

Cheers,

[pbonsalb]

Maybe BE is out of stock? There are also VAC and ACL extra clearance bearings.

[tweny]

Originally Posted by Scharbag

I will never understand the reasoning behind using a new set of OE bearings when extra clearance bearings are available from ACL, VAC and BE. Especially when you follow it up with "I'll change the to BE bearings and ARP bolts" in the very next sentence. What logic are you using to make this choice?

Good luck and I hope your engine is ok.

Cheers,

why would I ever buy oem if BE was available...

[330ciprem]

Originally Posted by tweny

why would I ever buy oem if BE was available...

If nothing else was available WPC coated OEM bearings would have been the second to last best choice.

But what's done is done. Hopefully, these will last longer for you.

[Scharbag]

Originally Posted by tweny

why would I ever buy oem if BE was available...

ACL and VAC are also options. Or, WPC stock bearings at the very least. And if you use ARP (VAC or BE) hardware now, then you can re-use it.

BE shows they have ARP hardware in stock. BE also shows that bearings should be in stock in 11 days from today. Given the time and ancillary costs (oil, gaskets, hardware) of changing bearings, I would just wait and do it once and do it right if that is your intent anyway.

Cheers,

[Bemo]

Originally Posted by pbonsalb

M3 Belgium has listened to audio of a lot of cars. Record yours and send it to him.

The only real way to diagnose rod bearings is to inspect them. It’s about 8 hours of labor to inspect them. Might as well change them since it’s no additional labor.

Seriously, dude should get nominated for and win an RB Grammy!

[tweny]

update: installed rod bearings today, put everything back together, turned the car on and the knock is still there. I took out the filter, cut it, and there was metal shavings in it. took out the oil pan, oil had metal in it. I'm thinking main bearings? I'm rather desperate at this point. drove the car for a total of 2000 KMs since buying it. looks like I'm gonna have to take the engine apart.

[tdott]

Originally Posted by tweny

update: installed rod bearings today, put everything back together, turned the car on and the knock is still there.

[6ixSpd]

Originally Posted by tweny

looks like I'm gonna have to take the engine apart.

...No. You're going to need a new engine. That's all there is to it, taking your current one apart won't yield any useful outcomes.

[tweny]

so my only option right now is a new engine?

[tdott]

Originally Posted by tweny

so my only option right now is a new engine?

Only way to know for sure is to tear down the motor and assess the damage. Most likely damage is to the rod, crank and/or block.

At that point your more cost effective option is with a used motor but you'll have to figure that out yourself as prices vary.

[Scharbag]

Originally Posted by tweny

update: installed rod bearings today, put everything back together, turned the car on and the knock is still there. I took out the filter, cut it, and there was metal shavings in it. took out the oil pan, oil had metal in it. I'm thinking main bearings? I'm rather desperate at this point. drove the car for a total of 2000 KMs since buying it. looks like I'm gonna have to take the engine apart.

Shitty deal.

Mains do not knock. If I were you I would take this to a proper engine builder and see what the problem is. Fix it properly if it can be fixed.