VAC Coated Rod Bearings, A FULL engine teardown after 39,500 Miles. Look inside!

[Dave07997S]

Just wanted to make sure that this post has been seen in this thread..

http://www.m3post.com/forums/showthr...1253084&page=5 see post #96.

Now I am really confused. I do see that these were just OEM BMW bearings with just Calico coating.

Dave

[Green-Eggs]

Originally Posted by Dave07997S

Just wanted to make sure that this post has been seen in this thread..

http://www.m3post.com/forums/showthr...1253084&page=5 see post #96.

Now I am really confused. I do see that these were just OEM BMW bearings with just Calico coating.

Dave

And just OEM rod bolts without the extra clearance caused by the bore distortion of the wrong clamping force of the rod bolts.

[Malek@MRF]

Originally Posted by Green-Eggs

And just OEM rod bolts without the extra clearance caused by the bore distortion of the wrong clamping force of the rod bolts.

And the bore distortion is "wrong" by what standard? Based on the measurements that the eccentricity is different than with OEM bolts, yet the bearings wear excessively with OEM bolts? Rod bore distortion is expected when a bearing isn't loaded into the rod and rod cap. The ARP hardware provides a more correct bearing eccentricity and bearing crush in comparison to the OEM bolts, which don't provide the proper clamp load for radial pressure between bearing/rod; this very fact is constantly being ignored repeatedly. It's visible with many S65 tear downs with the bearing wear patterns. The bearings either wear excessively at the parting lines, dictating an out of round bore, or wear prematurely near the top and bottom shells (upper shell between 10 and 2 O'Clock, and lower shells between 5 and 7 O'clock) demonstrating lack of crush from insufficient radial pressure.

[WickedE93]

Originally Posted by Malek@MRF

And the bore distortion is "wrong" by what standard? Based on the measurements that the eccentricity is different than with OEM bolts, yet the bearings wear excessively with OEM bolts? Rod bore distortion is expected when a bearing isn't loaded into the rod and rod cap. The ARP hardware provides a more correct bearing eccentricity and bearing crush in comparison to the OEM bolts, which don't provide the proper clamp load for radial pressure between bearing/rod; this very fact is constantly being ignored repeatedly.

Happy to say Malek will be doing my rod bearings on my car soon

[BMRLVR]

Originally Posted by Malek@MRF

And the bore distortion is "wrong" by what standard? Based on the measurements that the eccentricity is different than with OEM bolts, yet the bearings wear excessively with OEM bolts? Rod bore distortion is expected when a bearing isn't loaded into the rod and rod cap. The ARP hardware provides a more correct bearing eccentricity and bearing crush in comparison to the OEM bolts, which don't provide the proper clamp load for radial pressure between bearing/rod; this very fact is constantly being ignored repeatedly. It's visible with many S65 tear downs with the bearing wear patterns. The bearings either wear excessively at the parting lines, dictating an out of round bore, or wear prematurely near the top and bottom shells (upper shell between 10 and 2 O'Clock, and lower shells between 5 and 7 O'clock) demonstrating lack of crush from insufficient radial pressure.

Bore distortion is wrong by all standards. The OEM rods were designed to make a round rod big end bore with OEM bolts torqued to OEM spec. OEM bolts have never been shown to be a cause of failure nor have they been shown to provide insufficient clamping force.

The current APR fasteners sold by BE used with their recommend torque and lube will also produce a round bore. Loading a bearing shell into the big end will not stop this distortion from happening. The main reasons for the recommendation of ARP fasteners over the OEM bolts is for ease of install with a much simpler torque process, re-usability, and cost.

Your statement of bore distortion as being good, since most bearings you see coming out of engines look good is quite disturbing, especially for someone who claims to "know engines".

Rod big end bores need to be round, end of story. Eccentricity is determined by bearing shells not a distorted bore. All the issues in the S65 are a result of insufficient bearing clearance, on both the rods and mains. Once some miles are put on cars with BE bearings in them I think the bearing condition results will speak for themselves.

[Malek@MRF]

Originally Posted by BMRLVR

Bore distortion is wrong by all standards. The OEM rods were designed to make a round rod big end bore with OEM bolts torqued to OEM spec. OEM bolts have never been shown to be a cause of failure nor have they been shown to provide insufficient clamping force.

The current APR fasteners sold by BE used with their recommend torque and lube will also produce a round bore. Loading a bearing shell into the big end will not stop this distortion from happening. The main reasons for the recommendation of ARP fasteners over the OEM bolts is for ease of install with a much simpler torque process, re-usability, and cost.

Your statement of bore distortion as being good, since most bearings you see coming out of engines look good is quite disturbing, specially for someone who claims to "know engines".

Rod big end bores need to be round, end of story. Eccentricity is determined by bearing shells not a distorted bore. All the issues in the S65 are a result of insufficient bearing clearance, on both the rods and mains. Once some miles are put on cars with BE bearings in them I think the bearing condition results will speak for themselves.

I hear you on all this and not necessarily disagreeing or trying to be argumentative here, nor am I "claiming" anything. But this topic is starting to turn into a VAC vs. BE vs. OEM bearing and bolt debate and so forth. The information I am sharing is solely based on over 160 S65 (not including S85) rod bearing replacements and a couple dozen tear downs and 10 engines (cars which are heavily raced) with bearings replaced and pulled back apart, not theory. I don't have a dog in the fight and have nothing to gain from one vs. the other.

[JEllis]

Originally Posted by WickedE93

Happy to say Malek will be doing my rod bearings on my car soon

Since he is basically a one man show, he has probably completed more S65 bearing swaps, including mine, than most anyone outside of a dealership. You are in excellent hands.

[WickedE93]

Originally Posted by JEllis

Since he is basically a one man show, he has probably completed more S65 bearing swaps, including mine, than most anyone outside of a dealership. You are in excellent hands.

Thanks for the heads up, I defintely trust in Malek. He tells it like it is and always leads everyone in the right direction

[pooyab]

I plan on having mine done right when the warranty is done.
Is this the kit you are recommending Malek? Also, local shops charge around $2-3k for the job, does that seem fair?
https://store.vacmotorsports.com/vac...s65-p3479.aspx

Thanks in advance!

[whats77inaname]

Originally Posted by pooyab

I plan on having mine done right when the warranty is done.
Is this the kit you are recommending Malek? Also, local shops charge around $2-3k for the job, does that seem fair?
https://store.vacmotorsports.com/vac...s65-p3479.aspx

Thanks in advance!

Damn, is that $2k-$3k parts and labor or just labor?

[pbonsalb]

Around $2500 is the going rate for parts and labor. Parts are $500 to $1000 depending on bearings and bolts used, plus pan gasket and oil pump o-rings. Nothing else needs to be replaced to change the rod bearings. So labor is at least $1500 typically. Someone who has done the job a few times is probably doing it in 8 hours. Shops with experience that work hard can make more per hour. A first time DIYer can do it in 12 hours and save the labor, but should be confident in his skills to do a careful, competent job. This is more advanced than changing your brake pads, but certainly not beyond advanced DIYers.

[whats77inaname]

Originally Posted by pbonsalb

Around $2500 is the going rate for parts and labor. Parts are $500 to $1000 depending on bearings and bolts used, plus pan gasket and oil pump o-rings. Nothing else needs to be replaced to change the rod bearings. So labor is at least $1500 typically. Someone who has done the job a few times is probably doing it in 8 hours. Shops with experience that work hard can make more per hour. A first time DIYer can do it in 12 hours and save the labor, but should be confident in his skills to do a careful, competent job. This is more advanced than changing your brake pads, but certainly not beyond advanced DIYers.

I was curious as I sourced my own parts and paid $1500 in labor. I was trying to compare labor rates people are being quoted, that's all. I agree that this is an advanced DIY job, as I planned on doing my own, but with #brokenhandproblems and the plan to go FI before my hand heals enough to do the work, I wasn't left with much of a decision.

[AUSS1E]

Damn. No comments in over 2 yrs. I’m 50% into this job now. Really easy so far. I’ve read that some clean the bearing edges and some don’t. I’ll check the clearance and decide then. But likely I’ll just put them in as is. Thanks for the info fellas

[CHE///MIST3]

Originally Posted by AUSS1E

Damn. No comments in over 2 yrs. I’m 50% into this job now. Really easy so far. I’ve read that some clean the bearing edges and some don’t. I’ll check the clearance and decide then. But likely I’ll just put them in as is. Thanks for the info fellas

Cool ! I'm debating doing mine when I get my next M3, but I have seen some very nice DIY threads on this forum for doing the bearings that help tons. How are you checking the clearance before putting them back in? What would be the determining factor per shell ?

GM

[AUSS1E]

Originally Posted by CHE///MIST3

Cool ! I'm debating doing mine when I get my next M3, but I have seen some very nice DIY threads on this forum for doing the bearings that help tons. How are you checking the clearance before putting them back in? What would be the determining factor per shell ?

GM

just got finished. I checked the first one that I installed with the plastigage method. It was on the lower limit so I said if that one is good then all the others should be assuming none of the bearings were spun or worn a bunch more. A lot of people don’t check them at all. Besides. What are you going to do if it’s not good? Plus I spoke to vac and they recommend not sanding.

[d r i v e]

Hope it's not an annoyance to wake this thread up for a minute - some super helpful information in here; much appreciated!

Just curious if there has been any other developments/learnings over the past 1-2 years branching from the notes on VAC + arp bolts earlier in this thread. I'm considering getting my bearings replaced in the next few weeks, and most shops in the area are recommending VAC coated bearings (standard size) with arp bolts. Super aware this can be a bit subjective. I'm wanting to make sure I have the most up to date info and wondering if anyone has had any experience here since?

[Ant Man]

Originally Posted by Malek@MRF

Yes, I still use the ARP bolts, but the ARP bolts that are said to create distortion are the ARP625's. I do not use those ARP bolts in any of the rod bearing jobs I do.

I will continually use the combination of parts that has been working for many cars. Some of which have been taken back apart because they are raced frequently. These cars now show no wear much like the engine posted in this thread. Unfortunately I cannot comment on their main bearings as the engines have not been fully removed and disassembled.

In Regular Guy's post (#356) he says

"The ARP-2000 rod bolts did not create a perfectly round circle. The ARP-2000 rod bolts, with less clamping pressure produced bore distortion at 90-degrees. The bore distorts larger towards 90-degrees, and this would explain Malek's and Van Dyne's measurement of increased clearance when using the aftermarket ARP bolts. But is this enough to matter? Kawasaki00 told me privately, yes, this is a significant amount of ovality, and he would not use these bolts unless he was also able to rehone the connecting rod big ends to make them round again."

I believe he measured the ARP-2000 bolts you sent him but your own measurements do not show the above issue?

[Mvy]

Wanted to chime in. Running VAC coated G1 bearings + ARP 2000 rod bolts. They are thicker than factory as per post 1

My factory bearings were trashed when removing. Installed VACs at 47k miles in 2016. Now at 88k 2021 on a Harrop Supercharger. Redline every time I drive. Change the oil with Motul300 every 3-5k or once a year.

All is running fine. I have done oil analysis through blackstone every oil change since supercharging and no unusual wear over the 5 years. No increased aluminum. No flakes in the oil filters from the bearings (we check every time). No increased lead from the mains. Ill change again when I hit 100k miles and post pics. Its gonna be a while cause p cars.