Assimilator1 wroteIf anyone with spare rods would be willing to experiment with over torquing the OEM bolts that might be helpful to the community. My situation can't be the only one.GearKid wroteI wouldn't have thought it'd be a good idea to re-use an OEM bolt, they are stretch bolts, so once used I wouldn't think they'd yield anymore which could lead to over torquing?? Not a 100% on this though!It has all of us puzzled. The shop is legit as is the tech. He was explaining that he used the OEM bolt in order to get a clearance reading. Old bolt was tightened according to the procedure which worked fine for the previous 7 rods. This was #8. Claim is the bolt yielded right around 20N-m so it never had a chance to be over torqued.
This implies a pre-existing condition, which is saying that rod cap remained perfectly in place for 78k without any strange bearing wear. With the new APR bolt the tech was able to grab just enough thread to torque it down to 50ft-lbs but I'm not about to start it up and roll that dice.
I'm curious if anyone has experienced a rod stripping or if anyone with spares to experiment with can try to force one to strip. It would be really good to know if retorquing the old OEM bolt using the BMW torque procedure could cause this .
And, if he truly only did the 20 Nm stage then noway would that strip the threads. All very odd.
Btw, instead of buying a stroker motor (unless you really want to), how about buying a new rod and then having all the rods balanced? (still would need to strip it down of course).
1.2MVIEWS
3.2KREPLIES
3.1KAPPRECIATES
06-01-2026LAST POST
Assimilator1 wroteI believe if not most at least many shops have reused OE bolts when replacing shells back in the days. For instance one of the shops I chatted with, went with another thought. So no, I can't imagine that they would break by being re torqued.I wouldn't have thought it'd be a good idea to re-use an OEM bolt, they are stretch bolts, so once used I wouldn't think they'd yield anymore which could lead to over torquing?? Not a 100% on this though!
And, if he truly only did the 20 Nm stage then noway would that strip the threads. All very odd.
Btw, instead of buying a stroker motor (unless you really want to), how about buying a new rod and then having all the rods balanced? (still would need to strip it down of course).
Back in the days, as in older cars? If so they probably didn't have stretch rod bolts.
Depends when you mean and what cars
Depends when you mean and what cars
Assimilator1 wroteNo, incl S65 and S85. Mentioned local shop I mentioned are viewed as ///M experts in the Stockholm area. Didnt use them though cause didnt feel comfy.Back in the days, as in older cars? If so they probably didn't have stretch rod bolts.
Depends when you mean and what cars
Ah ok, interesting. I always thought re-using stretch bolts was a big no-no!
You are not supposed to reuse TTY rod bolts. I reuse some bolts that have angle torque specs like those for the front aluminum plate that stiffens the suspension, but I would not take the risk with rod bolts. If you were going to do it, you should measure for stretch against a new stock bolt.
You can't measure rod bolt stretch on OEM rods.
I assume you need a hole in the rod on the threaded end to place the gauge to the bolt?
I don't suppose you've got a pic or link to hand to show how it's done? (never seen it done myself).
And assuming you could measure OEM rod bolts in situ, would you reuse stretch bolts?
I don't suppose you've got a pic or link to hand to show how it's done? (never seen it done myself).
And assuming you could measure OEM rod bolts in situ, would you reuse stretch bolts?
Assimilator1 wrotehttps://www.m3post.com/forums/showpost.php?p=24786625&postcount=74I assume you need a hole in the rod on the threaded end to place the gauge to the bolt?
I don't suppose you've got a pic or link to hand to show how it's done? (never seen it done myself).
And assuming you could measure OEM rod bolts in situ, would you reuse stretch bolts?
I would think measuring stretch on a previously used rod TTY (stretch) bolt would be pretty meaningless because the bolt has already been to the point of yielding.
'12 E92.
Just replaced. As far as I know these are OEM, I bought the car in 2014 with 40k on the clock. Now at 95k. Includes around 40+ track days since 2014 and I changed oil every 5k miles.
Just replaced. As far as I know these are OEM, I bought the car in 2014 with 40k on the clock. Now at 95k. Includes around 40+ track days since 2014 and I changed oil every 5k miles.
Encouraging for that OCI !
I just got my rod bearings replaced. Replaced with BE bearings and ARP bolts, BW performance motor mounts.
2008 E90 6MT
97k miles
Bought the car in 2015 with 51k miles. Car has only 3 track days.
2008 E90 6MT
97k miles
Bought the car in 2015 with 51k miles. Car has only 3 track days.
Green-Eggs wroteAnd that's why I was thinking re-using them would be a bad idea.https://www.m3post.com/forums/showpost.php?p=24786625&postcount=74
I would think measuring stretch on a previously used rod TTY (stretch) bolt would be pretty meaningless because the bolt has already been to the point of yielding.
Thanks for the link btw, excellent quality photos!
330indy wroteMore likely down to the luck of the S65 lottery, that and LCI bearings generally coming out looking better than the earlier type.Encouraging for that OCI !
Chris_PDX wroteDo you still have your old bearings? And if so, would you be interested in doing a little experiment on one of them?'12 E92.
Just replaced. As far as I know these are OEM, I bought the car in 2014 with 40k on the clock. Now at 95k. Includes around 40+ track days since 2014 and I changed oil every 5k miles.
Assimilator1 wroteI'll have to check the garage, I honestly don't remember if I tossed them or not yet lol.A
Do you still have your old bearings? And if so, would you be interested in doing a little experiment on one of them?
Went with BE bearings, and BE ARP bolts. The car has had two previous owners before me. Original owner changed oil every 5k miles, and sold it to carmax with 12k miles on it back in 2016 I believe. Second owner bought it in 2016 with the carmax warranty, did oil changes every 6k miles, and took it to autocross and track days. I bought this car in January of 2021 with 42k miles. Decided to get them done now since the warranty is coming to an end this april.
2013 e92 m3
6 speed manual
45k miles today.
2013 e92 m3
6 speed manual
45k miles today.
Saw this from FCP Euro where a 300,000 Mille Volvo motor was torn down. Bearings looked better than just about every set in this thread.
drrust wroteIts a Volvo mate, built to last...Saw this from FCP Euro where a 300,000 Mille Volvo motor was torn down. Bearings looked better than just about every set in this thread.
Helmsman wroteYep.drrust wroteIts a Volvo mate, built to last...Saw this from FCP Euro where a 300,000 Mille Volvo motor was torn down. Bearings looked better than just about every set in this thread.
Just look how wide (heavy) that rod assembly is at the big end.
Lots of area to help the oil film do its job.
rod bearing change on a new to me 2008 at 122k
had a big scare at first with what appeared to be chunks in both oil pickups. turned out to be a dye, thankfully. still very interesting how exclusive the wear was to the top front shell halves.
had a big scare at first with what appeared to be chunks in both oil pickups. turned out to be a dye, thankfully. still very interesting how exclusive the wear was to the top front shell halves.
GearKid wroteDid the tech use the same pair of bolts for each test fit?It has all of us puzzled. The shop is legit as is the tech. He was explaining that he used the OEM bolt in order to get a clearance reading. Old bolt was tightened according to the procedure which worked fine for the previous 7 rods. This was #8. Claim is the bolt yielded right around 20N-m so it never had a chance to be over torqued.
This implies a pre-existing condition, which is saying that rod cap remained perfectly in place for 78k without any strange bearing wear. With the new APR bolt the tech was able to grab just enough thread to torque it down to 50ft-lbs but I'm not about to start it up and roll that dice.
I'm curious if anyone has experienced a rod stripping or if anyone with spares to experiment with can try to force one to strip. It would be really good to know if retorquing the old OEM bolt using the BMW torque procedure could cause this .
Wow! A couple of your shells were really bad!
(Was their any lead left on them??) 1 and 5 uppers, curious it's on the same pair....
Oh and all your close ups of the oil pick up are out of focus
(Was their any lead left on them??) 1 and 5 uppers, curious it's on the same pair....Oh and all your close ups of the oil pick up are out of focus
84k just taken out and replace with BE bearings
