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

[Malek@MRF]

Originally Posted by kawasaki00

I agree, arp would not make them if they were not safe. See below though


When we change bolts the rod needs to be honed to the new bolt to make the bore back round. It is never technically correct to change rod bolts and not hone the rod. We are cheating the system because not everyone wants to take the engine out of the car. Really what we are doing is half assing the bearing ordeal because of the method. Everyone needs to make sure to check bearing crush on each rod after changing. It can be done in the car. If people are not familiar with that method it is as such
Properly lube each bolt and torque both bolts to 120 in/lb, take one bolt back out while leaving the other tight. Use a feeler gauge on the edge of the fractured face to get a reading of the gap, I would never run anything under .004 crush. I can post a pic tomorrow when I get to work of this.
I am glad to see there multiple guys on here working to figure all this out.
Malek, can you torque up a rod or two with the new bolts and measure the housing bore and get a idea of how out of round it is without bearings?

It is semi-cheating in the regard you explained, because doing a rod bearing replacement doesnt constitute pulling the engine and tearing it down and starting from scratch. It doesn't allow us to spec the engine and basically "blueprint" to exacting specifications and move toward reducing and if possible eliminating tolerances. No matter what we do, whether bolts are the solution, or new bearings are the solution, it doesn't solve the issue of rod side clearance and the main bearing clearance.

I can definitely throw in some new bolts into a few of the same rods, and when I get the bolts back from regular_guy (he was interested in borrowing them for some of his own measurements), I will load them back up without bearings and measure the housing bore and provide the values. In the meantime, I can perform this with unused OE BMW TTY bolts and get the data. Are you curious if the bearings are distorting the rod bore with the ARP's in comparison to the OE bolts?

[kawasaki00]

Originally Posted by Malek@MRF

Are you curious if the bearings are distorting the rod bore with the ARP's in comparison to the OE bolts?

Curious how much the bore has changed with the clamp load difference between arp and oem. Would be good to take a rod, just brush it for round in the hone with oem bolts then place arp bolts in, dykem the rod housing and then brush it again and see how the bore changes. It might not change enough to really matter but I dont have any arp bolts to check this myself.
I also agree about that side clearance, that doesnt seem to be a problem with every engine, have looked at a few that it is a problem and a few not. None the less it still is another issue that unfortunately cant be fixed with the engine in the car.

[admranger]

Great thread that I just read from TDC to BDC?! Great work in here, Malek. Thanks to you and other who have helped (and RG for the bearing thread).

Perhaps my reading comprehension is off (I have heard this once or twice), but with these failed engines was there any engine oil analysis done at any time? I'm looking for precursors to the impending doom of bearing failure.

Thanks!

[regular guy]

Part-1: Rod bolt clamping pressure:

M3post reader, kawasaki00 measured the OEM rod bolt clamping pressure, along with the clamping pressure of two different types of Carrillo rod bolts. As he discovered, the OEM rod bolts offer far more clamping pressure vs. Carrillo rod bolts, and it's believed the clamping pressure (or lack thereof) may cause the rod big end bore distortion and lead to increased bearing clearance at 90-degrees. Increased bearing clearance is a good thing, but bore distortion is not. I'm pretty sure that increased clearance at the cost of bore distortion is not advised. However, I'll let kawasaki00 and the other engine experts comment on that.

Here's the rod bolt clamping force data generated by kawasaki00:

			At Torque	Over Torque
Bolt Type	53 in/lb	177 in/lb	130 degrees	+20 degrees
OEM Rod Bolt #1	1169	3075	10933	11570
OEM Rod Bolt #2	1101	2998	10855	11323
Bolt Type		22 ft/lbs	50 degrees	+20 degrees
Carrillo WMC #1		4200	8160	10211
Carrillo WMC #2		4189	8110	10301
Carrillo SPS		3270	7870

Notes:
Carrillo WMC bolts @ 50 degrees, 0.006 inch stretch
Carrillo SPS bolts @ 54 degrees, 0.0065 inch stretch


Part-2: Rod big-end ovality with different rod bolts:

With the rod bolt clamping data above, the next test will see which rod bolt creates the roundest circle. This will test for the "ovality" of the rod big end bore by checking the measurements at seven different points around the circle. Although the ARP-2000 and ARP-625 rod bolts were not tested above, I believe the two Carrillo rod bolts are of similar quality and specifications. (kawasaki00 can comment on that.)

For the most part, the OEM rod bolts create a near perfectly-round circle. Four of the eight rods I tested were 1/10000th of an inch or less out of round. That's probably what you would expect since these rods were honed (the process of making the circle round) with OEM rod bolts.

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.

The data:

OEM Rod Bolt Measurements:

Torque Specifications: 20 Nm + 130 degrees

Degrees	OEM Rod Bolts	R1	R2	R3	R4	R5	R6	R7	R8
	Ambient Temperature	76.4	76.3	76.2	76.1	76.0	76.1	76.1	76.0
5.00		2.20490	2.20495	2.20520	2.20500	2.20510	2.20520	2.20515	2.20510
19.75		2.20490	2.20500	2.20510	2.20500	2.20500	2.20520	2.20510	2.20510
45.00		2.20500	2.20510	2.20515	2.20520	2.20500	2.20500	2.20500	2.20520
90.00		2.20510	2.20530	2.20515	2.20540	2.20515	2.20510	2.20515	2.20520
135.00		2.20500	2.20520	2.20520	2.20520	2.20510	2.20515	2.20500	2.20520
160.25		2.20500	2.20510	2.20520	2.20500	2.20520	2.20520	2.20510	2.20515
175.00		2.20500	2.20500	2.20520	2.20500	2.20520	2.20530	2.20510	2.20515

Ovality:

Degrees	OEM Rod Bolts	R1	R2	R3	R4	R5	R6	R7	R8
	Ambient Temperature	76.4	76.3	76.2	76.1	76.0	76.1	76.1	76.0
5.00		-0.00005	-0.00002	0.00000	0.00000	-0.00005	-0.00005	0.00003	-0.00002
19.75		-0.00005	0.00002	-0.00010	0.00000	-0.00015	-0.00005	-0.00002	-0.00002
45.00		0.00005	0.00012	-0.00005	0.00020	-0.00015	-0.00025	-0.00012	0.00008
90.00		0.00015	0.00032	-0.00005	0.00040	0.00000	-0.00015	0.00003	0.00008
135.00		0.00005	0.00022	0.00000	0.00020	-0.00005	-0.00010	-0.00012	0.00008
160.25		0.00005	0.00012	0.00000	0.00000	0.00005	-0.00005	-0.00002	0.00003
175.00		0.00005	0.00002	0.00000	0.00000	0.00005	0.00005	-0.00002	0.00003

ARP-2000 Rod Bolt Measurements:

Torque Specifications: 45 Ft-Lbs

Degrees	OEM Rod Bolts	R1	R2	R3	R4	R5	R6	R7	R8
	Ambient Temperature	75.4	75.2	75.5	75.8	75.6	75.2	75.7	75.3
5.00		2.20500	2.20500	2.20520	2.20500	2.20520	2.20515	2.20520	2.20515
19.75		2.20520	2.20535	2.20540	2.20535	2.20540	2.20530	2.20540	2.20540
45.00		2.20560	2.20560	2.20560	2.20560	2.20550	2.20550	2.20540	2.20560
90.00		2.20575	2.20580	2.20580	2.20580	2.20560	2.20560	2.20565	2.20580
135.00		2.20560	2.20540	2.20565	2.20560	2.20550	2.20545	2.20540	2.20565
160.25		2.20520	2.20520	2.20530	2.20520	2.20535	2.20535	2.20530	2.20530
175.00		2.20500	2.20500	2.20520	2.20500	2.20520	2.20520	2.20510	2.20510

Ovality:

Degrees	OEM Rod Bolts	R1	R2	R3	R4	R5	R6	R7	R8
	Ambient Temperature	75.4	75.2	75.5	75.8	75.6	75.2	75.7	75.3
5.00		0.00000	0.00000	0.00000	0.00000	0.00000	-0.00002	0.00005	0.00003
19.75		0.00020	0.00035	0.00020	0.00035	0.00020	0.00012	0.00025	0.00028
45.00		0.00060	0.00060	0.00040	0.00060	0.00030	0.00032	0.00025	0.00048
90.00		0.00075	0.00080	0.00060	0.00080	0.00040	0.00042	0.00050	0.00068
135.00		0.00060	0.00040	0.00045	0.00060	0.00030	0.00027	0.00025	0.00053
160.25		0.00020	0.00020	0.00010	0.00020	0.00015	0.00018	0.00015	0.00018
175.00		0.00000	0.00000	0.00000	0.00000	0.00000	0.00002	-0.00005	-0.00002

Graph(s):



Next Steps:

Next week, ARP-625 bolts will arrive. I will repeat this measuring process with the ARP-625 bolts and post the results when they are available.

Thanks to Malek for loaning me the ARP-2000 rod bolts. Before returning them, I plan to measure bearing clearance.

[WhatsADSM]

I have only been half following these bearing discussions. But I find it interesting that there is a general disregard for the main bearings in these discussions. Especially given the fact that the OP here actually has had one of the motors with mains that likely failed prior to the rods.

It makes a world of difference in terms of the ultimate "fix" needed. As you can't really replace mains with the engine in the car.

Is there any data out there now on the number of S65s with failing main bearings relative to failing rod bearings?

BTW: Thanks for all the good work from everyone. I know these threads seem to get heated sometimes, but in the grand scheme of things it seems progress is being made!

[lutfy]

Folks,

Since there is not stupid question and I did use the search function, have a very simple question. I got my Calico bearing kit and the ARP (new gen) bolts based on what I have read on this thread.

Unlike factory which is marked with a color code, these are purely gray (obvious) but I cannot make of which side is which (top or bottom). Do I need measurements in this case? Any other way (small marking etc.) that I am missing out on? Instructions didnt say squat.

Secondly, anything else I need besides the bearing and bolts (engine oil pan etc.)? According to Turner, it was recommended that I get:

1 Genuine BMW Bearing Shell Yellow - 11217841609

1 Genuine BMW Guide-bearing Shell Yellow - 11217841613

I have not heard of these bearing shells and guide bearing shell. Are these required?

Thank you in advance, this will be my first DIY on the bearings for the S65 and want to make sure I have all the ducks in a row.

Malek, thanks for all the research.

Regards,

Lutfy

[regular guy]

Originally Posted by WhatsADSM

I have only been half following these bearing discussions. But I find it interesting that there is a general disregard for the main bearings in these discussions. Especially given the fact that the OP here actually has had one of the motors with mains that likely failed prior to the rods.

It makes a world of difference in terms of the ultimate "fix" needed. As you can't really replace mains with the engine in the car.

Is there any data out there now on the number of S65s with failing main bearings relative to failing rod bearings?

BTW: Thanks for all the good work from everyone. I know these threads seem to get heated sometimes, but in the grand scheme of things it seems progress is being made!

I'm aware of a few main bearing failures (maybe 3 or 4), but the failure rate seems very small compared to rod bearing failures.

[regular guy]

Originally Posted by lutfy

Folks,

Since there is not stupid question and I did use the search function, have a very simple question. I got my Calico bearing kit and the ARP (new gen) bolts based on what I have read on this thread.

Unlike factory which is marked with a color code, these are purely gray (obvious) but I cannot make of which side is which (top or bottom). Do I need measurements in this case? Any other way (small marking etc.) that I am missing out on? Instructions didnt say squat.

Secondly, anything else I need besides the bearing and bolts (engine oil pan etc.)? According to Turner, it was recommended that I get:

1 Genuine BMW Bearing Shell Yellow - 11217841609

1 Genuine BMW Guide-bearing Shell Yellow - 11217841613

I have not heard of these bearing shells and guide bearing shell. Are these required?

Thank you in advance, this will be my first DIY on the bearings for the S65 and want to make sure I have all the ducks in a row.

Malek, thanks for all the research.

Regards,

Lutfy

If you bought the new Clevite bearings from VAC, they will be stamped with "Clevite" on the back. If you have these bearings, then both tops and bottoms are the same; you don't need to measure. I do recommend scraping off the CT-1 material from the parting lines with a few swipes on 800 grit wet sandpaper.

If your bearings have 702/703 stamped on the back, then you will need to measure the bearing thickness to know which are the tops vs. bottoms. Tops will be about 0.0002 inch thicker than bottoms. Again, remove the material from the parting lines.

You might want to hold off doing the DIY until I have a chance to measure and post the results of the ARP-625 rod bolts. If you look at the graphs above for the ARP-2000 rod bolts, they cause about 0.0006 inch bore distortion. I've since measured this on other rods and saw up to 0.0012 inch bore distortion on the ARP-2000's. Based on the clamp load numbers kawasaki posted, I think the ARP-625's will distort as well, but not as much as the ARP-2000's. I recommend you to give me a few days to measure and post the results before making an informed decision whether you should continue with the ARP-625's.

BTW, Those are part numbers for main bearings. You don't need those for a rod bearing replacement.

[lutfy]

Originally Posted by regular guy

If you bought the new Clevite bearings from VAC, they will be stamped with "Clevite" on the back. If you have these bearings, then both tops and bottoms are the same; you don't need to measure. I do recommend scraping off the CT-1 material from the parting lines with a few swipes on 800 grit wet sandpaper.

If your bearings have 702/703 stamped on the back, then you will need to measure the bearing thickness to know which are the tops vs. bottoms. Tops will be about 0.0002 inch thicker than bottoms. Again, remove the material from the parting lines.

You might want to hold off doing the DIY until I have a chance to measure and post the results of the ARP-625 rod bolts. If you look at the graphs above for the ARP-2000 rod bolts, they cause about 0.0006 inch bore distortion. I've since measured this on other rods and saw up to 0.0012 inch bore distortion on the ARP-2000's. Based on the clamp load numbers kawasaki posted, I think the ARP-625's will distort as well, but not as much as the ARP-2000's. I recommend you to give me a few days to measure and post the results before making an informed decision whether you should continue with the ARP-625's.

BTW, Those are part numbers for main bearings. You don't need those for a rod bearing replacement.

Regularguy, yes they are the new ones from VAC.. this is helpful THANK you again. I am a simple guy (finance junkie) and appreciate the detailed response; I will wait to get update from you on the ARP-625.

Regards,

Lutfy

[Malek@MRF]

Originally Posted by WhatsADSM

I have only been half following these bearing discussions. But I find it interesting that there is a general disregard for the main bearings in these discussions. Especially given the fact that the OP here actually has had one of the motors with mains that likely failed prior to the rods.

It makes a world of difference in terms of the ultimate "fix" needed. As you can't really replace mains with the engine in the car.

Is there any data out there now on the number of S65s with failing main bearings relative to failing rod bearings?

BTW: Thanks for all the good work from everyone. I know these threads seem to get heated sometimes, but in the grand scheme of things it seems progress is being made!

This is a great point that you are pointing out as it seems to not get noticed as much as it should. The main bearings are also prone to failure like the connecting rod bearings are. The only true solution to correcting this engines faults is to remove it from the vehicle, fully tear it down and spec the engine clearances to the correct values for both the connecting rod bearings, connecting rod side clearance and the main bearing clearance.

The second engine in this thread failed due to the main bearings. There was no way around saving this engine even with a rod bearing replacement. In the other thread I've started with regards to rod bearing replacements, I will be posting up the results of another engine. That engine suffered from main bearing failure and the rod bearings looked rather terrible as well.

[marksae]

Originally Posted by regular guy

If you bought the new Clevite bearings from VAC, they will be stamped with "Clevite" on the back. If you have these bearings, then both tops and bottoms are the same; you don't need to measure. I do recommend scraping off the CT-1 material from the parting lines with a few swipes on 800 grit wet sandpaper.

If your bearings have 702/703 stamped on the back, then you will need to measure the bearing thickness to know which are the tops vs. bottoms. Tops will be about 0.0002 inch thicker than bottoms. Again, remove the material from the parting lines.

You might want to hold off doing the DIY until I have a chance to measure and post the results of the ARP-625 rod bolts. If you look at the graphs above for the ARP-2000 rod bolts, they cause about 0.0006 inch bore distortion. I've since measured this on other rods and saw up to 0.0012 inch bore distortion on the ARP-2000's. Based on the clamp load numbers kawasaki posted, I think the ARP-625's will distort as well, but not as much as the ARP-2000's. I recommend you to give me a few days to measure and post the results before making an informed decision whether you should continue with the ARP-625's.

BTW, Those are part numbers for main bearings. You don't need those for a rod bearing replacement.

regular guy, any updates with the ARP-625 rod bolt measurements?

[regular guy]

Originally Posted by marksae

regular guy, any updates with the ARP-625 rod bolt measurements?

Measurements all done. Just too busy to write an article and post it right now. I promise, I will get to it.

[LangRacingDevelopment]

Originally Posted by regular guy

You might want to hold off doing the DIY until I have a chance to measure and post the results of the ARP-625 rod bolts. If you look at the graphs above for the ARP-2000 rod bolts, they cause about 0.0006 inch bore distortion. I've since measured this on other rods and saw up to 0.0012 inch bore distortion on the ARP-2000's. Based on the clamp load numbers kawasaki posted, I think the ARP-625's will distort as well, but not as much as the ARP-2000's. I recommend you to give me a few days to measure and post the results before making an informed decision whether you should continue with the ARP-625's.

BTW, Those are part numbers for main bearings. You don't need those for a rod bearing replacement.

As a data point, I tried the same test with the Carrillo WMC bolts to try to determine what a safe torque spec would be in the stock bolt. at 50 ft/lbs the bore of the rod seemed to come in nice and round, no more than .0003" of distortion when using the same procedure on several rods with several different bolts. I then used a different rod as a fixture to measure stretch at that torque and found it to be at .006", within their specs. Since this bolt is stronger than the ARP 2000 it seems to make sense that the 2000 would not clamp the rod enough to round the bore. I would think that at 60 ft/lbs with the ARP 625 that you might end up with a distorted bore from excessive clamping force. The 625 bolts are on backorder but I ordered a few sets for inventory.

I assume you'll post up what you find on the 625's very soon though.

[stosh1]

Hey guys, sorry for the slight thread-jack here, but I figured that this was as relevant a thread as any to ask people's opinion(s) on the proper break-in procedure (either after bearing replacement and/or total engine failure/rebuild)? I'm not a stranger to engine rebuilds and have performed a few rebuilds/swaps over the years, but just wanted to hear thoughts on how we're doing it w/our BMW engines. Specifically interested to hear thoughts on:

-break-in oil type
-break-in duration & when to change break-in oil
-oil brand/type after break-in (this has been pretty much beaten to death, & is still controversial & a bit subjective, but would entertain further comments)

TIA!!!

EDIT: Sorry, forgot! Just wanted to thank Malek & everyone else real quick for all of their hard work, and for the knowledge that they have willingly and openly shared on this forum!

[javarithms]

Originally Posted by stosh1

Hey guys, sorry for the slight thread-jack here, but I figured that this was as relevant a thread as any to ask people's opinion(s) on the proper break-in procedure (either after bearing replacement and/or total engine failure/rebuild)? I'm not a stranger to engine rebuilds and have performed a few rebuilds/swaps over the years, but just wanted to hear thoughts on how we're doing it w/our BMW engines. Specifically interested to hear thoughts on:

-break-in oil type
-break-in duration & when to change break-in oil
-oil brand/type after break-in (this has been pretty much beaten to death, & is still controversial & a bit subjective, but would entertain further comments)

TIA!!!

EDIT: Sorry, forgot! Just wanted to thank Malek & everyone else real quick for all of their hard work, and for the knowledge that they have willingly and openly shared on this forum!

No break in period if you are replacing only the rod bearings, since there are no metal shavings. 1200 miles, although some people go for 600 miles, of break in period (change oil at the same time) when you replace the engine since there will be metal shavings from the rings wearing in.

No special oil during break in period, use 10W-60 or whatever grade you feel comfortable with.

[stosh1]

Originally Posted by javarithms

No break in period if you are replacing only the rod bearings, since there are no metal shavings. 1200 miles, although some people go for 600 miles, of break in period (change oil at the same time) when you replace the engine since there will be metal shavings from the rings wearing in.

No special oil during break in period, use 10W-60 or whatever grade you feel comfortable with.

Thanx for the response! Sooo, doesn't really sound like anything too much different from breaking in any other engine. Any specific oil/weight that you guys recommend for the break-in period (for a new/rebuilt engine)? Any thoughts on breaking in w/conventional motor oil vs. synthetic?

[decimation1]

Not sure if I missed it or not (this is a great, long informational thread), but did Malek hone the big ends of the rods with the new bolts during the original bearing swap of the engine this thread was started about?

Just curious because I just spun a bearing on rod #2 (2008 80k manual never tracked) and a low mileage used engine is on my short list. That being said, before I drop the (n)used engine in I was planning on proactively doing the VAC/ARP treatment.

Thanks!

[ASBSECU E93]

Bump - any updates?

[LangRacingDevelopment]

Originally Posted by Malek@MRF

This is a great point that you are pointing out as it seems to not get noticed as much as it should. The main bearings are also prone to failure like the connecting rod bearings are. The only true solution to correcting this engines faults is to remove it from the vehicle, fully tear it down and spec the engine clearances to the correct values for both the connecting rod bearings, connecting rod side clearance and the main bearing clearance.

The second engine in this thread failed due to the main bearings. There was no way around saving this engine even with a rod bearing replacement. In the other thread I've started with regards to rod bearing replacements, I will be posting up the results of another engine. That engine suffered from main bearing failure and the rod bearings looked rather terrible as well.

Malek is making a really good point here that seems to be glossed over in all of the other discussions. If bearing clearance is the issue with the S65 engine, then what is the point of replacing only the rod bearings? The main bearings will still be overly tight and it will do nothing for the tight rod bearing clearance. The rod side clearance is also tight and is not addressed at all at the moment.

If you really believe that bearing clearance is the issue with this motor, you should be removing the crankshaft, having the journals polished down, and installing the loosest main and rod bearings you can find.

Why is the rod bearing clearance the only focus here?

[BMRLVR]

Originally Posted by LangRacingDevelopment

Malek is making a really good point here that seems to be glossed over in all of the other discussions. If bearing clearance is the issue with the S65 engine, then what is the point of replacing only the rod bearings? The main bearings will still be overly tight and it will do nothing for the tight rod bearing clearance. The rod side clearance is also tight and is not addressed at all at the moment.

If you really believe that bearing clearance is the issue with this motor, you should be removing the crankshaft, having the journals polished down, and installing the loosest main and rod bearings you can find.

Why is the rod bearing clearance the only focus here?

You are asking these questions, but I am quite sure you know the answers yourself.

It is known that the main clearance is also tight, but they don't seem to fail since there have only been 3 cases that I can recall of main bearing failure being posted on here.

The rod bearings are done because there have been lots of cases of rod bearing failures and they can be done without pulling the engine. In the event of someone doing a full engine rebuild, it is recommended by all of us rod bearing c/o proponents to have the rod side clearance set and crank journals polished to size. The fact of the matter is that most people are not going to be doing full rebuilds so they address the method of failure that is most prominent by doing the rod bearings.

[bigsurge]

BUMP !!!!!!!!!!!

So is the jury still out on which rods to use ?

I have seen tons of guys replace with ARP bolts, should they open it up again and use OEM?

[Malek@MRF]

Originally Posted by bigsurge

BUMP !!!!!!!!!!!

So is the jury still out on which rods to use ?

I have seen tons of guys replace with ARP bolts, should they open it up again and use OEM?

I have opened up many cars now that had bearings replaced, were raced/tracked/driven on average 10,000+ miles and came back in for check ups. The new bearings just like the one posted in this thread exhibit no wear.