# Assembling 24valve 2.9L VR6--Main bearing Clearances....



## Snitches Get Stitches (Jul 21, 2007)

I have my freshly machined block back from machining, and I am having issues with clearances on bearings. 
All journals look amazing, and I am seeing uniform numbers across the block, but way too low. The crank has been knife-edged and fully balanced.
This is with ARP Billet Main Caps + Studs---block was align-honed. Also, these are 034 coated main bearings. I was told these were OEM bearings sent out for coating. We are using platigage after taking our time tourqing to 60ft lbs as per ARP instructions. 
So plastigauge is giving is 0.001....after wipingdown everything on bearings, crak, etc...we eventually saw 0.0015...We are looking for 0.0025 and up.
So I have ordered up OEM bearings and hoping that the coatings are not thought out well, and are giving me the problems.
Anyone ever see these issues in building an engine and checking main clearances? 
I havn't even gotten to rod bearing clearances--which are also 034 coated OEM bearings that I had rifle drilled to match the Int. Engineering Rod's w/ rifle drilling.
Please, Please, Please be the coating on the stupid bearings...


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## KubotaPowered (Jan 27, 2005)

*Re: Assembling 24valve 2.9L VR6--Main bearing Clearances.... (Snitches Get Stitches)*

I don't like using the coated bearings for that reason. I have yet to see a good rebuild on new stock bearings fail on a FI VR6. Stick with what works


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## Snitches Get Stitches (Jul 21, 2007)

Yea, I guess I am learning this lesson by purchasing more parts I thought I had already handled. What a pain in the ass. I really thought the ceramics would be an upgrade, rather than the pain in the ass they are becoming. And searching on here doesn't point to any or alot of others with these issues. Are people just not checking their mains and rod clearances or is someone else assembling their block for them??
I was able to find out that if you clean and rub down all bearings and main journals free of all assembly lube, you do gain back 0.0005 tolerances....but my clearances are still way to tight to run. The OEM main bearings should be here today, so I am hoping for the best tonight.
My next issue is with the Rod bearings that also are coated by 034 mtorsports. I had my machine shop rifle drill these bearings to match my Integrated Engineering rifle drilled rods. I already have a set of OEM rod bearings, and I am going to try to mail them to the machinist for rifle drilling today, so that I can have 2 sets to choose from when we check Rod bearing clearances in the next few days, and I won't be back to waiting for parts.
I am not even at the interesting part of assembling the R32 head. I have already had a P&P, as well as a 5 angle valve job on the stock valves. Head will also have 034 dual springs, matching titanium retainers, and TT 260/264 cams.
More bits of the build are:
2.9L JE Pistons 8:5:1 comp with ceramic coating on domes and skirts
GT3582R T4 0.68ar-- coated hot side
Pag Parts Coated Log Manifold
3inch dp with wg reroute coated by Swain
O2m w/ peloquin
South Bend clutch and steel flywheel good to 475+ft lbs of torks


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## KubotaPowered (Jan 27, 2005)

*Re: (Snitches Get Stitches)*

I think what it is, is that the bearings are just not that popularbecause there isn't a need for them. One the other side of that coin, I think you hit the nail on the head, there are fewer people assembling their own blocks, and out of those that do, I don't think many check the tolerances, just torque the caps and run it. With tolerances as tight as you are seeing, a spun bearing could very well have resulted.


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## Snitches Get Stitches (Jul 21, 2007)

Now I emailed Javad at 034 just to let him know about the clearance issues I am seeing. He informed me that their coatings are 0.0003 and effects should be negligble. The Bentley and online sourrces show I should be seeing almost 0.004 as far as clearances on the mains.
Javad also said that he has had no reports of bad bearings or clearances being that out of wack.
I am still waiting for the non-coated OEM bearings to arrive and try plastigage again here. I have double and triple checked the ceramic coatings and after cleaning all journals and bearing surfaces, I am still sitting at way below 0.002 clearances.
This is a 2.9L 24v block bored for 82mm JE's
ARP billet main caps + studs -- block was line honed
I am seeing uniform clearances on all caps and great taper on the plastigage. This is telling me that the crank is straight and true, and the machine work was all done right.
Crank has been knife-edged and balanced as well.
So if for some weird reason, the OEM non-coated bearings do not give me the 0.003+ clearances I am looking for, any other ideas out there for what could cause this?
Anyone know where to find undersized bearings for the VR6 motor?
Can't wait to see what issues the rod bearings may provide.


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## GinsterMan98 (May 19, 2008)

*Re: (Snitches Get Stitches)*

what lube are you using on the cap studs? 30w oil, arp lube or other?
Are the main caps original? you could mic check the block with the cap installed with no bearing to ensure the machine shop didn't miss a decimal.


_Modified by GinsterMan98 at 1:47 PM 4-20-2010_


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## sdezego (Apr 23, 2004)

*Re: (Snitches Get Stitches)*

I ALWAYS check. I will not build a motor w/o checking.
It is unclear from what you wrote though, are you checking with crank, bearing and caps completely dry? no oil? Because that is a must if you are not. Just don't turn the crank and you will not scuff the bearings.
I have never used the coated bearings. My thought is that the stock ones are good for over 100k miles easy, so why mess with a good thing.
Also, are you using the plastigauge perpendicular to he journal?


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## Snitches Get Stitches (Jul 21, 2007)

Redline assembly lube....plastigage perpendicular to journal. And we have pulled the crank and all bearings twice now to wipe down and make sure everything is dry.
These are ARP Billet Main Caps--will be getting the micrometer out and mic'ing everything as soon as the non-coated bearings show up.
I don;t see this machine shop making an error, but anything is possible.


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## GinsterMan98 (May 19, 2008)

*Re: (Snitches Get Stitches)*

I ment the lube you used on the ARP studs and nuts. I know the the torque will change if you use something other than ARP lube. I believe the value increases if using 30w oil or moly. Don't know if this would cause this to happen though.


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## Snitches Get Stitches (Jul 21, 2007)

The lube used on the ARP studs was what came with the studs-ARP lube. We have repeated these steps so many times now, we may be out of the original lube that came in the small packet and may have to use the Redline assembly lube on my next try. OEM bearings just showed up today, so I will update when we try again tonight or tommorrow.


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## SlowVRT (Jan 3, 2009)

*Re: (Snitches Get Stitches)*

Good luck, I am interested to see what happens. http://****************.com/smile/emthup.gif


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## rhussjr (Aug 7, 2000)

*Re: (Snitches Get Stitches)*

Undersized bearings will not fix your problem, as they are made for journals that are "undersized" or reground to a smaller diameter. Coated bearings usually require a second polishing of the journals to get the added clearances required. But do check with a set of stock bearings first just to make sure that nothing is out of whack with your findings.


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## Snitches Get Stitches (Jul 21, 2007)

Problem Solved.....Went back to machine shop with crank in hand. 2nd time micropolishing this crank following the knife-edging, lightening, and balancing. I am also running ceramic coated bearings all the way around this motor(Main bearings and Rod bearings sourced from 034)

























Clearances are good all around. Bottom end is buttoned up, with oil system in place. The R head is next on the To Do list. This is a R32 24v head that will go on my 2.9L bottom end. 
ARP Billet main caps + studs
Integrated Engineering rifle drilled rods
ARP 625+ rod bolts
82mm 8:5:1 JE pistons(dome and skirt ceramic coated)
The head is an R32 head sourced from Issam. I believe it is out of a Toureg. I am using the stock valves, with a 5 angle valve job. 034 Dual Spring kit with titanium retainers and a set of TT 264/260 cams will help me safely rev to 8200rpm. C2 management is already in hand, but I do need to order injectors to match. 550cc will be used. Down the road, possibly in a different vehicle, I will look to do a Pro-Maf and a big bump in injector and possibly a GT40. This would be in AWD set up WAY WAY down the road.
























Block is powdercoated BMW Performance Gold. 
























Downpipe custom made by Arnold @ Pag Parts plus Pag Exhaust Manifold
Downpipe is coated by SwainTechnologies White Lightening. Manifold and hotside of turbo is also ceramic coated by Arnold.
















Garrett GT3582 T4 w/ precision covers 0.68AR put together by Pag Parts








AWIC system w/ trunk mounted resevoir:









Thanks for looking. This is a 3+ year build that has had its ups and downs. After way too much time planning, purchasing, and finally building, I plan on having my 24v VRT on the road before the end of the year.


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## huichox4 (Nov 8, 2004)

Well it seems that you have the issue resolved, but My machinist mentioned that the coated bearings sometimes need a bit of rubbing with a scotch green pad for this same reason. I guess I was too late for you instead of going back to the machinist. 

I am using those 034 bearings and so far so good. over 400+awhp and 460+awtq I will be pushing more now that my setup changed but still need to figure out an electrical bug :banghead:

Also HPA uses coated bearings I think so they must be good.


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## INA (Nov 16, 2005)

KubotaPowered said:


> I don't like using the coated bearings for that reason. I have yet to see a good rebuild on new stock bearings fail on a FI VR6. Stick with what works


I am pretty sure I read this thread and attempted to reply to it but then got side tracked.

FWIW , Bentley W12 bearings are coated from the factory and the 034 coated bearings are the same as what Calico has been offering.
I have read some comments across the forum where people say "dont buy the 034 bearings , buy Calico"

6 of one , half of dozen of the other....nothing wrong with coated bearings considering the cost involved to get them (less than 40% over what the OEM bearings are worth).

Looking good Joshua.


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