ACl Rod bearing question

[Syfon]

You can plastigauge with stock bolts.

I don’t think I’ve seen anyone say the ARPs provide insufficient clamping force— just that they provide less clamping force (and a less round bore than ARP bolts torqued to their spec with their lube). The Oe bolts are also cheaper.

AKA. The ARPs are fine. But, the OE’s are cheaper, stronger, and rounder result, at the cost of marginally more effort to the job. Seems like an easy enough choice to me.

I went with ARP's as I was in there diy'ing the motor build, and chances are the sump will come off again at some stage to inspect the bearings (likely within ~10-15,000km).

[Icecream]

You can plastigauge with stock bolts.

I don’t think I’ve seen anyone say the ARPs provide insufficient clamping force— just that they provide less clamping force (and a less round bore than ARP bolts torqued to their spec with their lube). The Oe bolts are also cheaper.

AKA. The ARPs are fine. But, the OE’s are cheaper, stronger, and rounder result, at the cost of marginally more effort to the job. Seems like an easy enough choice to me.

Getting a smooth 105* in a single stroke 36 times consistently isn't fun and opens more opportunity to mess up so I get the appeal. Honestly if people have had long term success with ARP bolts (greater than 50k hard miles, none of this "my ARP bolts and rods were perfect after 5k miles" bs), it may be a better way to go if the engine is not removed from the car and if you are doing this job on your back.

[S54B32]

BMW state the M10 rod bolts must not be reused?

I've never read anywhere they can be reused albeit not more than 5 times?

Mine was never opened (to my knowledge), yet I didn't reuse the stock m10 rod bolts. I went with arp rod bolts.

My post stated that the whole thing regarding arp rod bolts not providing sufficient clamping force may be true, however the clamping force differential would be miniscule, otherwise by now, we would have seen many s54's with arp rod bolts having failed where the failure could be directly and solely attributed to the arp rod bolts and their insufficient clamping force. Many people I know have built s54's with arp rod bolts (installed by torqueing to spec, and not by stretching), and they haven't failed after many thousand km's of hard street and track driving.

Sure, don’t reuse the bolts. But during the procedure you can loosen and retight the new bolts.
Here are 2 screenshots from the official bmw procedure:

[Syfon]

Sure, don’t reuse the bolts. But during the procedure you can loosen and retight the new bolts.
Here are 2 screenshots from the official bmw procedure:

Yeah I didn't do that. I torqued the arp bolts to spec for my plastigauge checks

[RaliusM3]

Just adding my $.02, I used ACL standard besrings on my 93K mile 2002 M3 and am having zero issues. Clearance was nominal at .002” when I plastigaged.

[maupineda]

I am thinking using ARP and get their stretch gage, not as hard as 105deg and still appropriate for longevity

[tlow98]

I also bought ACL bearings. In metric they all fell between .045 - .055mm clearance which is just about perfect. This is on a 200k+ mile motor.

I will be using ARP M11 bolts as mine was an early car and the rods will be honed (correct verbiage?) to match the ARPs at the correct bolt stretch.

After removing and installing the stock bolts and then passing them to the machinist I don’t trust that the same bolt will go back into the correct bore when it’s all said and done. That means ARP is the safest way for me to go. Also, the stockers would have had 6+ torque cycles by the times the motor is back together.

we’ll see!

[Slideways]

I also bought ACL bearings. In metric they all fell between .045 - .055mm clearance which is just about perfect. This is on a 200k+ mile motor.

I will be using ARP M11 bolts as mine was an early car and the rods will be honed (correct verbiage?) to match the ARPs at the correct bolt stretch.

After removing and installing the stock bolts and then passing them to the machinist I don’t trust that the same bolt will go back into the correct bore when it’s all said and done. That means ARP is the safest way for me to go. Also, the stockers would have had 6+ torque cycles by the times the motor is back together.

we’ll see!

From what I recall, there used to be a thread on M3F where Andrew Lang tested the ARP M11s and said that they do not distort the bore like the ARP M10s.

[tlow98]

From what I recall, there used to be a thread on M3F where Andrew Lang tested the ARP M11s and said that they do not distort the bore like the ARP M10s.

This is my understanding, but I figure as long as the machinist has it all I’ll just make it right as best I can.