164S rebuild...engine apart

[Richard2]

Sometimes I feel sooo lucky! My 164S engine that was in the Black car that I bought in 1993 or 1994 with 19,000 miles now has 167,000 miles. The black car was totaled and I'm rebuilding the engine for a red 164S.

The engine is apart now and was so close to destruction I feel very lucky. I think it was caught in time. Here's some very interesting pics:

1st one is of a split nut holding on rear main bearing cap. It was like that when I pulled the pan.

2nd is the rear main bearing cap with the bearing. It was just starting to hammer the bearing in one spot.

3rd is rear main journal. Still looks good

4th is damaged #4 rod bearing

5th is light marks on #4 rod journal. They aren't deep. I think they'll buff out.

6th is #4 rod bearing fit to the #4 rod. Notice how much smaller the bearing is in diameter than the rod hole.

[Richard2]

Here's the final 2 pics. Sorry this isn't too well organized. I can't figure out how to put comments under each pic.

[Del]

Very interesting. Strengthens my opinion that the #4 rod journal is insufficiently lubed for the v-6 engine? Others have reported the same #4 damage or more.

I would think, however, that when that rod cap is tightened and torqued, you would find that the bearing should be snug in the rod. Check it with Plastigage to find out what you get. That will be something to check out, comparing against the other rod big ends.

You will have to check the clearance of the bearing shell itself against the crank journal as well for each of the rods. I don't remember what the bearing shell clearance is supposed to be, shimmed if needed, against the journal, but the bearing mustn't run tight against the journal, but then you most likely know that. The journal bearing clearance has to be sufficient for the proper oil wedge to more or less form. Maybe the required bearing clearance for the #4 bearing is slightly too little for that poorly lubed #4 journal. In that case the rod big end would have to be reamed ever so slightly to increase the insufficient clearance of the bearing against the journal.

While I've always used 20W-50 (I have always warmed up the engine at 1k-1.5k rpm for a minute or so to hopefully avoid bearing wipe) in the S, if it didn't use so much oil, I would use 15W-50 Mobil or the ilk. I would use at least 15W-50, or even the costly 10W-60 in the higher powered version v-6's. I do use 15W-50 Mobil in the LS, since it uses no oil. Might try some of the 10W-60 in it. A cold engine needs a thin oil at cold start up to ensure quicker oil flow to the rods.

[Richard2]

All other rods bearing fit just fine in the rod. Only #4 bearing has re-arced itself into a different shape so it no longer fits the rod hole. Probably due to the heat, or bearing material redistribution.

I tend to agree on the lack of lubrication on #4.

I've run Mobil 1 in this engine for 148,000 of it's 167,000 life. I bought the car with 19,000 and don't know what the PO used. Mostly I ran 20W-50. In -20 deg Wyoming winters I used 10W-30, all Mobil 1.

[Del]

Usually, when the bearing shells are tightened in the rod, they assume the required round shape, but they shouldn't be oval to start with, lol. The size of the reamed hole in the rod big end is very critical.

[Alfisto Steve]

I suggest you get that crank mic'ed on all journals and rod check for roundness.

[Richard2]

Yes, Steve, that's in the plan. When I get all the parts here, there's a trip to the machine shop with the block, crank, rods and pistons. I'll pull the liners, have them checked out and honed, have the crank cleaned and checked, have the rods check and the block line bored. Everything will be checked before it is put back together. The heads have gone via Wes Ingram to Hannafords in Tacoma. Wes expected them to be 2 months, so I have a little time. I'm checking parts prices right now.

Any one have a spare nut for a bearing cap?