DIY: E46 M3 S54 detailed rod bearing replacement and front suspension refreshment

[beemer_guy]

Posted by Lang Racing on the old M3F:

https://langracing.com/s54-rod-bearing-and-bolt-replacement-with-arp-fasteners/

https://nam3forum.com/forums/forum/m...ting-rod-bolts

I have read that thread before too, it was hard for me to decide since it seemed like so many people were getting the ARP bolts instead of OE for the ease of use (sans gauge) for both pre/post LCI models, but since I've already got all these parts I'm trying to work with what I have. I did just get off a call with ARP and I think we found a solution, I misunderstood how to pre-load the gauge, which is what I was about to test when literally right after I hung up the gauge began malfunctioning big time. After another call they'll be checking it out and potentially send a replacement if we can't figure out what is wrong.

[beemer_guy]

Just got the replacement gauge, I already plastigauged the rest of the bearings and installed of them with the bolts torqued to 68 Nm just so I could safely rotate the crank, but now I'll be backing them off and trying to stretch them properly later tonight. I've begun putting other stuff back together and it feels so good to be nearly done with this stage. Every bearing reads at about .045mm - .050mm which was nice since it's pretty much in the middle of the range, as far as I can reasonably tell.

I just need to clean the oil pan and remove all the RTV from every single bolt hole then I'll be ready to button it all back up.

Edit:
Adding info here, I edited one of my previous posts to correct some info as well. Firstly, the first gauge I had definitely had an issue with retaining zero so I'm glad I got the replacement, secondly, I misunderstood the dial indicators and was thinking on literally a scale 10X higher than what I should've been. For the .0065 - .0070" range I needed it is only 13-14 small tick marks on the gauge, and pretty much the 68 Nm gets me there for each bolt, or almost and I just need to go slightly higher. It explains a lot of my confusion, and I'm glad I caught it after banging my head against the wall for so long.

[beemer_guy]

I finally finished stretching all the bolts to spec as best as I could tell, with a couple of minor mishaps along the way, but I am impressed by the repeatability of the results with ARP's lube, along with how accurate the 68 Nm was for pretty much getting it either within the stretch range or pretty darn close. I overstretched one bolt because I can't differentiate between adding and subtracting apparently, but measuring it after backing it off shows it only yielded less than half of the .001" ARP warns against, so you'd really have to over-torque the bolts to deform them; if I had to guess, to the tune of maybe 15 - 20 Nm (11 - 15 ft-lbs.) over the 68 Nm (50 ft-lbs.) value.

Final results were as follows:

Cylinder 1 Bolts:	Torque Value	Stretch Value
Bottom	69.6 Nm	.0069"
Top	67.3 Nm	.0067"
Cylinder 2 Bolts:	Torque Value	Stretch Value
Bottom	70.0 Nm	.0069"
Top	69.1 Nm	.0069"
Cylinder 3 Bolts:	Torque Value	Stretch Value
Bottom	70.0 Nm	.0069"
Top	79.1 Nm	.0067"
Cylinder 4 Bolts:	Torque Value	Stretch Value
Bottom	71.4 Nm	.0069"
Top	78.4 Nm	.0069"
Cylinder 5 Bolts:	Torque Value	Stretch Value
Bottom	68.4 Nm	.0069"
Top	69.4 Nm	.0067"
Cylinder 6 Bolts:	Torque Value	Stretch Value
Bottom	72.1 Nm	.0066"
Top	80.9 Nm	.0067"

Cylinder's 3, 4 and 6 had high torque values on the top bolts because I was trying to incrementally increase the torque and overcome the friction instead of if I had gotten it in one pull.

Lessons learned through this process:

• Don't use a freaking pick to remove bearings, I could've saved myself a lot of time and money by being patient in removal and then re-using the nice BE bearings that were already there had I not messed them up
• Pre-load the dial indicator properly as per the instruction sheet, I misunderstood how pre-loading worked and it was skewing my results. For the final results I had the new gauge pre-loaded at .200"
• Don't confuse the scale of the units
• Understanding the actual increments on the stretch gauge and how the required stretch range translates. Like I mentioned before, the ideal range on the indicator would've been at the 13-14 tick marks to hit the .0065" - .0070" range