Connecting Rod Bolts

[Andrew 06M3Cab]

I am about to undertake changing the rod bearing shells. My car is an 06, so it has the updated rod M10 connecting rod bolts.

I have read that nevertheless, it is worthwhile to upgrade to ARP bolts for the minimal additional cost. When I went to source them, I could only find them on Turner's website. I called ARP directly and the person I spoke with said they don't make the rod bolts for the post 02/2003 S54. When I did a bit more digging, it appears that Turner has actually listed the M10 ARP bolts for the S50 Euro engine from the e36 M3.

Does anyone know if these are actually directly interchangeable with the S54 engine?

TIA.

[Obioban]

Get stock. They're cheaper, have more clamping force, and create a rounder bore than ARP. They are a downgrade, not an upgrade. Only downside is they're a bit more of a PITA to torque.

[Bigo1087]

Get stock. They're cheaper, have more clamping force, and create a rounder bore than ARP. They are a downgrade, not an upgrade. Only downside is they're a bit more of a PITA to torque.

This x2

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[Andrew 06M3Cab]

thanks. much appreciated.

[Syfon]

ARP rod bolts for the Euro S50B30 are suitable in application for LCI E46 M3's; i.e. S54's with M10 bolts.

https://arp-bolts.com/kits/arpkit-detail.php?RecordID=1108

Pre-LCI variants with the M11 bolts should use the following product; https://arp-bolts.com/kits/arpkit-de...?RecordID=1109

[Thoglan]

Syfon I can see the argument for prefacelift and not being comfortable reusing old bolts, not sure why you wouldn't go OE for a facelift M3 tho. Especially since the arp have been shown to oval the rod bore.

[BMWahba]

I need to find out what bolts my 12/15/2002 build car has. The TSB states that cars built after 12/13/2002 are using updated M10 bolts....so being 3 days away from that cutoff I wonder if I had a 3 day older engine or something and have M11 bolts, lol. FCP says cars after 2/2003 have M10's. Weird.

[tnord]

BMW didn't really utilize a VIN cutoff or anything for the transition to updated parts in any scenario that I'm aware of. The build date on mine indicates I should have the HP DME, but when I pulled it out for the CSL conversion, it wasn't. On my old E39 I should have had the updated ZF transmission, but it was actually the old GM from pre-LCI. BMW just uses however many old parts they have in inventory until they run out and switch to the new one.

[BMWahba]

BMW didn't really utilize a VIN cutoff or anything for the transition to updated parts in any scenario that I'm aware of. The build date on mine indicates I should have the HP DME, but when I pulled it out for the CSL conversion, it wasn't. On my old E39 I should have had the updated ZF transmission, but it was actually the old GM from pre-LCI. BMW just uses however many old parts they have in inventory until they run out and switch to the new one.

Yep, exactly what I've seen too. I think I'm just going to wait until I open her up and then order if I need.

Another question I do have.... as far as I understand, BMW didn't sell replacement M11 bolts, as they were very specific in mentioning you should reuse them and mark their locations.

Is this a problem if I've already had the rod bearings done on my car once before? So these bolts would be re-used twice now, if I do have the older M11 style? Perhaps ARP would be a smarter move in this scenario?

[bjz!]

Like obioban said, ARP, are a downgrade in this case. Stick to oe

[BMWahba]

Like obioban said, ARP, are a downgrade in this case. Stick to oe

For sure if I had newer bolts I would stick to OE. Mainly wondering in the case I have older M11 style that have already been reused once.

[TexaZ3]

Like obioban said, ARP, are a downgrade in this case. Stick to oe

Not if OE bolts have stretched to the point where they can't clamp right, after being used multiple times. That is what he is asking.
I honestly have no problem with with ARP fasteners, and don't necessarily subscribe to the theory of them ovaling the bore.

[bjz!]

Not if OE bolts have stretched to the point where they can't clamp right, after being used multiple times. That is what he is asking.
I honestly have no problem with with ARP fasteners, and don't necessarily subscribe to the theory of them ovaling the bore.

Just buy them. In Europe are availables.

[Mr.wReckless]

My car apparently was an November 02 car, but when I did the rod bearings, I found I had the newer M10 bolts. I wonder whether my car has had an engine recall or swap in it's life at some point.

FWIW I used APR bolts regardless. Though now gone I seem to recall Andrew Lang had a long test on the old M3 site with roundness/ovality with the older and newer style ARP bolts, and I seem to remember he got the newer APR bolts within round spec, but only by using the stretch gauge method rather than torque and stretching them to the max recommended spec by ARP. I'm not going to worry about it tbh, my bearings were due when I changed them and hopefully this out of round is not as big of a deal.

Regards

[elbert]

I honestly have no problem with with ARP fasteners, and don't necessarily subscribe to the theory of them ovaling the bore.

Because of the metallurgy of ARP bolts, you typically need to torque them more than factory spec to get sufficient bolt stretch (which provides the clamping force). This extra torque can cause the bores to ovalize.
Having said that, I don't know the torque specs for this application, but this does happen with their other engine bolts. To correct this, the bores need to be honed with bolts in place to correct the ovalization.