Stock Rod Bolt Torque

[Alex]

Does anyone know the connecting rod torque? BMW Workshop states 20NM and 70 degrees, new TIS says 20NM and 70 degrees, then 70 degrees again. I think one place even stated 20NM and 70 degrees 3 times loosening in between.

Here are the links to where I saw the info.

http://workshop-manuals.com/bmw/3_s..._bearing/2_azd__connecting_rods_and_bearings/

https://www.newtis.info/tisv2/a/en/...engine/11-24-connecting-rods-bearings/5rMcGF1

 

[DennisKing]

20nm and 140 degrees is what I did. You don't do 20nm and then 70 and then back it off and do 70 again. You do 20nm and 140.

I did this not long ago. Have fun.

 

[Alex]

20nm and 140 degrees is what I did. You don't do 20nm and then 70 and then back it off and do 70 again. You do 20nm and 140.

I did this not long ago. Have fun.

You mean 70 and 70? 140 in one stroke should not be the same as 70 and 70. Did you verify the bearing clearance via PG-1?

 

[DennisKing]

You mean 70 and 70? 140 in one stroke should not be the same as 70 and 70. Did you verify the bearing clearance via PG-1?

Nope
20nm and then 140 degrees in one stroke
No. I was fixing a car that I needed to sell. In the S65 amd S54 engines, there is no call in the workshop manual for plastigauge as part of the repair when doing new rod bearings.
Do you have the breakdown of how to determine what rod bearings you need (yellow, red, blue, purple)

 

[Alex]

Nope
20nm and then 140 degrees in one stroke
No. I was fixing a car that I needed to sell. In the S65 amd S54 engines, there is no call in the workshop manual for plastigauge as part of the repair when doing new rod bearings.
Do you have the breakdown of how to determine what rod bearings you need (yellow, red, blue, purple)

Well now i'm even more confused since that contradicts TIS and the workshop manuals. Generally when doing rod bearings i've checked the new bearing clearance with the old rod bolts for the s62 and s52s and the n54 calls for that as well in order to know whether or not the new bearings are in spec.

My crank was imprinted "rrrrrr" so i believe that is yellow rod bearing side bearing and red for the cap side bearing for all rods according to TIS. I'm basically pulling a cap off to check the bearing wear and then i was gonna throw new bolts into just that rod depending on how bad the wear is.

 

[DennisKing]

Why not just take an oil sample. It will save you a few hours.
Just talk to Blackstone labs and get a sample bottle. Send it off. They'll let you know if there is any nickel or chrome in the oil from the bearings.
In my repair, I was replacing a spun rod bearing. I already knew it was failed.
And yes, rrrr is yellow and red bearings.

 

[Alex]

Why not just take an oil sample. It will save you a few hours.
Just talk to Blackstone labs and get a sample bottle. Send it off. They'll let you know if there is any nickel or chrome in the oil from the bearings.
In my repair, I was replacing a spun rod bearing. I already knew it was failed.
And yes, rrrr is yellow and red bearings.

Just out of curiosity were yours all "rrrrrr" as well? I called VAC and they told me they only sell once size bearing unless specified so I'm wondering if "rrrrrr" is the standard size however there is "bbbbbb" and oversized bearings for each as well.

I am actually doing this on a replacement 93k mile motor I bought. In terms of blackstone, the motor I just had fail had just gotten a black stone analysis with "really good" results for my 118k mile motor. With blackstone you also want to warm and drive with the oil, the motor in question is already on a stand with the oil pan off waiting for bearings.

 

[DennisKing]

Gotcha. That's not good to hear about Blackstone. I was wondering how you knew that your crank was engraved rrrr without the pan already off. Now I know.
I'm not sure about bbbb but you just never know with BMW

 

[Alex]

Gotcha. That's not good to hear about Blackstone. I was wondering how you knew that your crank was engraved rrrr without the pan already off. Now I know.
I'm not sure about bbbb but you just never know with BMW

Yeah but to be fair im pretty sure this engine failure was caused by a bend rod which led to ringland execution via low end aggressive torque so i dont think black stone would have been able to forsee that.

Do you remember what your rod bearing colors were?

 

[DennisKing]

I do.
I did red and yellow. rrrr on my crankshaft. I bought all 4 colors and returned the ones I didn't use.

 

[Alex]

I do.
I did red and yellow. rrrr on my crankshaft. I bought all 4 colors and returned the ones I didn't use.

Awesome, so VAC probably stocks the red and yellow. I guess im gonna have to get TIS for a day since i keep seeing different torque specs all over the place.

Do you by any chance have the clearance values? I found one on another forum but it didnt seem too official.

 

[DennisKing]

I don't have the clearance values. I bought my bearings at the local dealer. Same pricing and they were able to take my returns immediately.

 

[AD-ENG]

Rod clearance on the N54 is pretty loose stock. I would focus on the proper torque procedure as keep the big end bore round is keep. 0.0032" +/- .0003" isn't of concern.