Main & Rod Bearing Size

[All_talk]

Well I got my engine completely torn down this weekend, all and all I don’t think it looks to bad for 250,000 miles, but is definitely in need of new bearings. I think the crank will be fine, tho I may look around for another because the keyway is a little chewed up.

Anyway, looking at the FSM I see four sets of numbers for crank and rod bearing/journal sizes, STD (standard), 0.03mm, 0.05mm and 0.25mm undersize. First question, did any engines come from the factory with the undersize journals (like the “A, B, C” piston sizing)? Or were they all standard. Second, is there any way to tell whats in my engine now? Do the numbers on the block, crank, rods or bearings tell me anything? At the moment I don’t have anything accurate enough to get a proper measurement (just my digital calipers), I may be able to borrow a 3” micrometer from work next week.

If it helps…

Numbers stamped on top of block (piston code)
Right half 80 BB
11211
Left half BB80
(the “80” looks like an 8 with a rectangle)

Numbers on the Crank
BCBCB 1111
290223

Rod numbers
#1 ALF/LF 45
#2 ALA/LA 45
#3 AKZ/KZ 45
#4 AKY/KY 45

Main bearing numbers
#1 A17X DOH A
#2 A17X D9F B
#3 A17X OF A
#4 A17X D9D A
#5 A17X DOH B

Rod bearing numbers all read DOH A

Thanks
Gary

[douglas vincent]

I have done 4 (?) motors so far and just used "standard" ACL bearins off of EBAY and been happy.

[All_talk]

I knew Doug would have some advice. Have you ever checked the oil clearance by mic or plasigauge?

Gary

[douglas vincent]

I have never done the plasigauge test.... Subaru is Perfect!

[icrman]

Makes me think about what I've mentioned in other posts. About rebuilds.

[AWD_addict]

Gary I'm in the same boat as you right now. I don't have any visible damage other than the bearings being worn down, but I don't want to put in the wrong parts.

I talked to my local helpful Subaru parts guy and he said standard size should be fine unless machining work has been done. When they need to repair a customer shortblock they just put a new shortblock in, so his advice may not be the ultimate authority. But since Doug says the same thing, then it must work.

I'm probably just going to use standard size OEM bearings.

[douglas vincent]

Makes me think about what I've mentioned in other posts. About rebuilds.

Subarus are not rocket science. They are legos. The cranks are NEVER out of spec, but I will give you the .001 percent whack chance.

Do you have a problem with me?

I have yet to have a failure over 4 years of fucking around with crazy shit. The low hp NA crap hasnt failed yet.

[n2x4]

Makes me think about what I've mentioned in other posts. About rebuilds.

From the "other posts":

Not with subaru but many other brands have witnessed so called top rebuilds bite the dust.

We're still talking Subaru, none of those "other brands". You said it yourself, you weren't referring to Subaru rebuilds.

Doug's a Subaru builder. I'm sure he knows what he's doing .

[lunes]

so, if you were to theoretically want to plastigauge it, how would you do that on these anyway? I'm in the process of a teardown, and I haven't split one of these blocks before (I have an ej22t) and I'm throwing some upgrade internals at it, and I don't really want to do the crank and mains without being CERTAIN the specs are met to a T...

[douglas vincent]

http://www.plastigaugeusa.com/how.html

[lunes]

yeah, I get that, Ive done that with other types of engines, specifically muscle car style v8s, and Chevy 4 cylinders, I was just curious as to how it was done on the flat 4, but I'm guessing I have to split the block, reassemble, then split again, and reassemble, right?

[bmxpunk]

I can testify to what doug said as well. When I built my block a few months back, my bearing clearences were exactly in the middle of the specs, with new bearingson the old crank shaft. Also my buddy actually built his block today and we checked his tolerances with the plastiguage.

anyway my buddy used a different crank than what came out of his block, replaced the bearings and the tolerances were in the middle of specs, just like my block, both on crank and rod bearings.

[93forestpearl]

yeah, I get that, Ive done that with other types of engines, specifically muscle car style v8s, and Chevy 4 cylinders, I was just curious as to how it was done on the flat 4, but I'm guessing I have to split the block, reassemble, then split again, and reassemble, right?

You are pretty much correct. I like to check the mains before assembling the rods on the crank because its less hassle. But yeah, bolt the block together with plastigauge to check your mains, then do the same for your rods. Rinse and repeat.


I've done a couple and nothing was ever out of spec. Right in the middle of the tolerance. First time was with Clevite bearings, which after tearing it down, I'm not to fond of anymore for the rod bearings. Now I've got a set of Cobb rod bearings in there and hopefully they are better. They sure looked pretty when they went in.

[MichaelNZ]

Well I got my engine completely torn down this weekend, all and all I don’t think it looks to bad for 250,000 miles, but is definitely in need of new bearings. I think the crank will be fine, tho I may look around for another because the keyway is a little chewed up.

Anyway, looking at the FSM I see four sets of numbers for crank and rod bearing/journal sizes, STD (standard), 0.03mm, 0.05mm and 0.25mm undersize. First question, did any engines come from the factory with the undersize journals (like the “A, B, C” piston sizing)? Or were they all standard. Second, is there any way to tell whats in my engine now? Do the numbers on the block, crank, rods or bearings tell me anything? At the moment I don’t have anything accurate enough to get a proper measurement (just my digital calipers), I may be able to borrow a 3” micrometer from work next week.

If it helps…

Numbers stamped on top of block (piston code)
Right half 80 BB
11211
Left half BB80
(the “80” looks like an 8 with a rectangle)

Numbers on the Crank
BCBCB 1111
290223

Rod numbers
#1 ALF/LF 45
#2 ALA/LA 45
#3 AKZ/KZ 45
#4 AKY/KY 45

Main bearing numbers
#1 A17X DOH A
#2 A17X D9F B
#3 A17X OF A
#4 A17X D9D A
#5 A17X DOH B

Rod bearing numbers all read DOH A

Thanks
Gary

Hi I know this is old but I have just come across this thread while searching the web for this very problem. There is little information out there so I though I would share and hopefully save some people some money for the wrong bearings.

So for above
Right half 80 BB
11211
Left half BB80
The 80 should match as this indicates that the two crank case halves are a matched pair
The letters refer to piston sizes the is an A Size and a B size, usually there would be a mixture of A's and B's.
The 11211 refers to crank bearing sizes, 1st number is bearing #1 5th number bearing number 5.
1 refers to standard bearing size
2 refers to 0.03mm undersize
3 refers to 0.05mm undersize
So for the example above crank case bearing;
1) STD
2) STD
3) 0.03 undersize
4) STD
5) STD

My engine's crank bearing code was 22332 so no standard bearings would fit and sure enough when I plastigauged the new set of standard bearings they were all out of specifications. I hope this saves someone else some money.

Numbers on the Crank
BCBCB 1111
The 4 numbers indicate all 4 rod bearings are standard size much like the crank case example above. A 2 or 3 would indicate oversize big end bearings are required.

[cj91legss]

That information helps a lot. I always wondered what those 5 numbers were for.

[Legacy777]

Michael,

Welcome to the BBS and thanks for sharing that information!