Stock 1G teardown, 1 green rod bearing?

[DSMJim]

So in pulling my 1g motor appart to rebuild it with some forged internals I find this...

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Top and bottom are green kinda like how on a Honda they have different colored bearing for different sizes.

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This is what all three other rods were like, no color.

So here is my question.. Has that rod bearing been oversided and the crank ground down? Everybody I talk to doesn't seem to know and has never seen that before. All the bearings look like they have the same wear and the motor was in otherwise good shape. It doesn't look like it was ever taken appart from the factory when I dis-assembled the motor so I'm really not sure.

 

[aero_sallee]

I know some companies do code them that way. Usually it will be stamped on the backside of the bearing also. I say just measure it, get some accurate dial calipers. You should be able to tell for sure that way.

 

[GTM]

...

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Top and bottom are green kinda like how on a Honda they have different colored bearing for different sizes.

You must be logged in to view this image or video.

This is what all three other rods were like, no color.

So here is my question.. Has that rod bearing been oversided and the crank ground down? Everybody I talk to doesn't seem to know and has never seen that before. All the bearings look like they have the same wear and the motor was in otherwise good shape. It doesn't look like it was ever taken appart from the factory when I dis-assembled the motor so I'm really not sure.

A quick check of the internet solved it. I had seen the paint marks before but thought they were just quality control inspection. All the bearings I've seen were stamped on the outside of the shell.
http://engineparts.com/motorhead/techstuff/clrcode.html

Cheers,
GTM

 

[DSMJim]

I realize that, however it's only the one bearing that has the color on it. I'm afraid that it's oversized on one rod and was ground down and rebuilt. If thats the case then my crank is junk which is a real pissoff...

All honda bearings are sized and colored like that from the factory and they are sized specifically to the rod or main they are in and stamped in the block afterwards. Thats why when I saw the green I became nervous that my crank had been machined.

Still no word from the machine shop, they are gonna size the crank and make sure they are all the same.

 

[GTM]

I realize that, however it's only the one bearing that has the color on it.
...
Still no word from the machine shop, they are gonna size the crank and make sure they are all the same.

I looked at the pictures again and what I thought was yellow must have been the camera flash on the second pict.

Are you going to race this engine and pull a lot of extra hp then you might be concerned. If it's just a daily driver then I wouldn't be worried about the what I thought was .005" undersize based on the green and yellow color I perceived.

Cheers,
GTM

 

[trbotaln]

The only way to find out is to measure it with a micrometer. I doubt that they had only one of the rod journals ground. Usually they just grind all of the rod journals and/or all of the mains together but you never know.

 

[DSMJim]

OK, well I'm gonna sit tight for now until the machine shop calls back and gives me the news on whats happening.

I have never seen that on a DSM engine before so I'm not really sure whats going on, but at any rate, there ins't much point in worrying about it now until I know what the size of everything is. If it's ground then I'm gonna have to get a new crank no big deal.

 

[blue1]

I think you will find that on the final assy line the person that is assy' that part of the engine puts an air check measuring divice on it and it has come up .001 under so they have special bearings to suit and just put the bearing in to suit the journal, take a real close look at the crank because there should be a paint spot near that journal aswell. Its common practice on the final assy lines with all the engine manufacturers i have seen the codes and the explainations on a link on here! if i find it i will post it!

 

[danl]

Are they OEM mitsu bearings? If so on the assembly line they might have put a special sized bearing in their like honda does to prevent from scrapping a batch of cranks what were machined a tenth of a thousanths or so wrong. If so the special coating on the 6 bolt crank could still be their meaning that you would not have to scrap it. You would just have to buy a new bearing with oversize/undersize fitting (such as clevites) and plasticguage it, just like a honda.

The reason we don't reuse cut cranks is because of the special coating.
[Nitriding. It's more a treatment than a coating, trivial point.]

 

[DSMJim]

Well the crank was measured and everything is fine. All are the same size. Why one bearing has green markings on it is beyond me. The machine shop measured them all and they are exact not even like .001 difference like we thought may have been the case. So it's going back together now with pistons and rods and should be pretty good.... Glad I didn't have to find a crank.

 

[GTM]

Well the crank was measured and everything is fine. All are the same size. Why one bearing has green markings on it is beyond me. The machine shop measured them all and they are exact not even like .001 difference like we thought may have been the case. So it's going back together now with pistons and rods and should be pretty good.... Glad I didn't have to find a crank.

That should make you happy. I still would be interesting to know if these were factory bearings that were being classified as having very minor fitting differences so you would not mix one half shell green with a yellow. When you buy a set you are never presented with that option but I remember when you could pick and choose from broken sets at the dealer. The same was true of pistons, where you could select from size and weight classifications.

So when is this going to be running?

Cheers,
GTM

 

[TimG]

Yeah Jim, if you ever need some parts (crank too), off a 91 6-bolt, I have one just 2 streets down from you. Shoot me an MSN or PM on ca.dsm or tuners and I'll see what I got.

 

[DSMJim]

I should have the motor back today and be able to re-assemble it into a full long block with everything ready to go. After that im waiting on Magnus for my trans. That could be a while...