Rod Bearings

[Harwoodandy]

I was just wondering what peoples thoughts are on replacing rod bearings?

Do you treat it as a routine preventative maintenance task, or is this age of engine unaffected?

has anybody experienced bearing failure?

My 02 M3 was recalled under warranty and had them replaced but the general consensus seems to be replacement at 100k....

TIA

Andy

[Brendanmck]

Changed mine at 89000 miles reason being I had had the front subframe off the car so it made sense to change them. I was very surprised as was my mechanic who has done quite a few rod bearing changes just how little wear there was on the old bearings. But it's good peace of mind to change them anyway. As I'm sure no two engines wear the same.

[Chad]

Originally Posted by Brendanmck

Changed mine at 89000 miles reason being I had had the front subframe off the car so it made sense to change them. I was very surprised as was my mechanic who has done quite a few rod bearing changes just how little wear there was on the old bearings. But it's good peace of mind to change them anyway. As I'm sure no two engines wear the same.

Did mine recently at 68k mileage. Glad I did as number six rod bearings shell counting from the front , seemed to have the most wear, and didn’t look happy,but was still in spec, using plastiguage, I only did the shells because my head gasket had gone on number 1-2 , confirmed which compression test before I stripped head off ,, as I’ve previously mentioned not sure if wear to number six shell has a link to blown gasket on numbers 1-2 ,, As they are on opposing strokes possibly some kind of imbalance loads,, just a thought

[niall1]

Same as Chad. I changed mine at similar mileage as a preventative maintenance and glad I did as they were starting to show signs of wear.

[rstoughy]

Serviceable part IMO on these cars now.
Its been pretty well documented that they will require changing usually at anything over 50k.

I've done the race car (with all OEM parts)
In the process of doing the M5 (ACL Extra clearance bearings & OEM everything else)
And will do the CSL when it comes out of storage (with all OEM parts)

I would not entertain the ARP bolts unless you are going down the road of swapping out the conrods as well.

[Chad]

Originally Posted by rstoughy

Serviceable part IMO on these cars now.
Its been pretty well documented that they will require changing usually at anything over 50k.

I've done the race car (with all OEM parts)
In the process of doing the M5 (ACL Extra clearance bearings & OEM everything else)
And will do the CSL when it comes out of storage (with all OEM parts)

I would not entertain the ARP bolts unless you are going down the road of swapping out the conrods as well.

As above I’d go oem bolts, oem shells ,, that what I used , i also did the piston rings while it was in bits ,, when I measured the ring they definitely needed doing going off oem spec ,, for them I used npr rings, as far a I could see they are identical to the oem , if indeed they aren’t oem ,,, measured up perfectly,,, A fraction of the cost of oem ,, ps also wouldn’t hesitate in king race they are also 0001 more oil clearance ,, I’ve got king race shells ready to go in ongoing project inc mains shells and npr rings .. and elring head gasket kit I believe it’s oem anyway ,, saves a small fortune, As far as mileage rod shell failure is concerned I think it’s a bit of a lottery Even if it’s had regular oil changes you can’t be sure shells are still perfect ,, prevention is better as they say ,, another thing to add even with to copper colour showing they not always out of spec, when checked with plastiguage,, but saying that I’d prefer to see them still showing the gray colour coat ..

[Harwoodandy]

Originally Posted by rstoughy

Serviceable part IMO on these cars now.
Its been pretty well documented that they will require changing usually at anything over 50k.

I've done the race car (with all OEM parts)
In the process of doing the M5 (ACL Extra clearance bearings & OEM everything else)
And will do the CSL when it comes out of storage (with all OEM parts)

I would not entertain the ARP bolts unless you are going down the road of swapping out the conrods as well.

Thanks for the replies all - pretty much same consensus as E46 M3 fraternity.

Why not use the ARP bolts?
King racing shells and ARP bolts seem to be the favoured combination on the standard motor....
Not challenging - just curious

Thanks again

Andy

[Chad]

Originally Posted by Harwoodandy

Thanks for the replies all - pretty much same consensus as E46 M3 fraternity.

Why not use the ARP bolts?
King racing shells and ARP bolts seem to be the favoured combination on the standard motor....
Not challenging - just curious

Thanks again

Andy

Oem tried and tested,, as far as I know don’t think there is a specific arp torque or sequence as oem have ,, I believe it’s all about checking dimensions eg out of round rods and bearings/ oval ,, probably doing them yourself easier to just go oem ,,