Author Topic: Attention anyone rebuilding an engine: MAIN BEARING FAILURE (Read 4349 times)

Dr. Diesel · « **on:** August 28, 2004, 09:25:46 am »

As my new engine troubles enter their second month (driven it 3 days, not in a row, had it apart 4 times, all in less than 2 months) I thought I was nearing the end. Not so. After reassembling the engine from bare bones AGAIN, I went to pick up the freshly done tranny (a four hour job that took 2.5 months)
ok. this is turning into a rant.

BOTTOM LINE:

2 piece style #3 crank bearings (the ones with the thrust face on them) WILL RUIN YOUR CRANKSHAFT. There is a good reason that the VW engineers used a 6 piece #3 main bearing. AE Clevite/Federal Mogul/whatever/whatever thought they could cut a corner and make a simple two piece #3 bearing. Well, they sure did. They cut the corner right off the thrust face of my balanced, polished and shot peened crankshaft, which is now sitting in a scrap heap.

Symptoms are a drop in idle speed and/or a scraping noise when you step on the clutch, and bearing pieces in your oilpan.

Avoid 2 piece #3 main bearings like a double dose of clapto-ouchitburns scrotulabial nudgeacervixitus!

Greasemonkey · « **Reply #1 on:** August 28, 2004, 01:35:06 pm »

I have personally used Kolbenschmidt 1 piece thrust bearings on a 2L 16v with no problems whatsoever. The motor has done 3 years and 40-50K since. I'd say KS one piece brgs are ok.

Dr. Diesel · « **Reply #2 on:** August 28, 2004, 10:58:58 pm »

these ones are north american made, AE clevite. A friend who's run a VW shop for ages now has seen this problem time and time again, notably in diesels. Just a warning, take it how you may.

ps, have you looked at it?

Greasemonkey · « **Reply #3 on:** August 30, 2004, 06:09:08 pm »

I will take your warning very seriously. I generally don`t use american parts on my cars as a rule tho.

I haven`t inspected that bearing but it has given me no reason to. Oil pressure is normal and has been the same during this time, no funny noises when stepping on the clutch, etc....

Dr. Diesel · « **Reply #4 on:** August 30, 2004, 06:13:13 pm »

I've recently heard that this failure is almost guaranteed to happen on a diesel, and not unheard of in gas. No idea why. Luckily, I was able to fanagle the questionable two-piece bearing out, and install a 6 piece without removing the crank, just the #3 cap.

v8volvo · « **Reply #5 on:** August 30, 2004, 06:32:09 pm »

I saw this happen in a gasser 16-valve motor. Not a myth, this really does happen. Seems like not guaranteed, since plenty of rebuilt diesels are surely running around with American bearings, but very possible. When I rebuild mine, it'll be all German.

DieselsRcool · « **Reply #6 on:** August 30, 2004, 07:52:55 pm »

I just tossed a crank and block in the scrap heap a few months ago because of this exact problem. I figured .080" end play was too much. I was right. It was a fairly new Canada VW rebuild too. Suck! :x

Centurion · « **Reply #7 on:** August 31, 2004, 05:27:53 am »

could you post a pic of the offending bearing?

I have this job on the ToDo list in the near future!

C - Thanks!

81rabbit · « **Reply #8 on:** August 31, 2004, 05:00:19 pm »

Could you also post a pic of the "6-piece" style as well? since I haven't seen one before.

Author Topic: Attention anyone rebuilding an engine: MAIN BEARING FAILURE (Read 4349 times)

81rabbit