I was in the middle of a clutch job on my 04 MCS (my throwout bearing seized up), and I got my flywheel off, and I've noticed I have a fair bit of play in my crankshaft. My mini has 190k miles.

I measured the amount of play in the crankshaft, and it was over 1mm. I took off my oil pan and took a video of what's going on. See
So... What's the best solution to the problem? It seems like my thrust bearing is going out. Replacing seems rather pricey, because I'd need a new crankshaft, a new thrust bearing at a minimum, and a bunch of bolts for the connecting rods. Reassemble it and drive it till the engine explodes? I can use the money I save to start looking at a JCW.

If you suggest the repair route, do you know where I can get a crankshaft and/or main bearing for a decent price? I'm not totally broke, but I don't want to send a fortune on my project car. Best I've found on ebay is ~525 for the crankshaft. I'm guessing that'll put it at 700 in parts. I can get a new-ish engine for 1500 or so. And I'll have my current engine for parts.

Edit: This is for street use, I don't take it out to the track. I also have a backup vehicle, so I'm not stranded, just trying to figure out what to do.

 

Going to move you to the Stock Problems and Issues area. Hopefully somebody like Nick at Detroit Tuned or Way at Way Motors will chime in. They are both vendors here but also have full service repair shops.

 

Never had a Mini engine apart but I've been inside a few other engines. Generally there is a main bearing with extra big flange on it which is part of the thrust bearing. The crank has a machined/polished surface that is intended to run against this flange. The flange can wear and crankshaft end play increases.

I don't know what the tolerance is for your engine but I suspect 1mm is out of tolerance. Generally for other engines the end play is on the order of just a few thousandths of an inch.

What you can do is remove the crank. Using a micrometer measure all the main and rod bearing journals looking for any undersized. Be sure to measure the journal diameter at 3 places. In the center and at either side to check for a bearing with tapered wear or uneven wear.

If you find the journals don't have enough wear to be out of tolerance then you can order new bearings and reuse the crank as is. (Well, after a thorough cleaning including the oil passages in the crank. I used a suitably sized rifle cleaning kit to clean these oil passages.)

if you find one or more bearings undersized the crank might be still usable but it would need to have the undersized bearings ground down just enough to use an oversized bearing or bearings. For a street engine there is no need to resize and use oversized bearing for every journal just the worn journals.

'course, the above assumes the factory -- or an aftermarket company -- offers oversized bearings and these are available separately.

Or the crank journal can be ground slightly undersized, then built up with hard chrome (some cranks tolerate this some don't, so you'll have to speak to a shop that specializes in Mini engine rebuilds to know) and then ground to size and new bearings then can be used.

Last but not least found this. You might find it a worthwhile read:

http://www.mini2.com/forum/first-gen...387-miles.html

 

Thanks for the help. I think I know what's wrong, but I don't have enough experience to know what to do. Here's a diagram of the engine if it helps. http://www.realoem.com/bmw/enUS/show...diagId=11_3091 I believe I was showing the main bearing in the video. You can see one side of the edge of it, and it looks nice and smooth. The other looks rather beat up, and worn unevenly. There's a noticeable lip in it (I think).

That matches a lot of what I've already read, that helps. Yeah, the tolerance is .30 mm max, I'm at 1mm+, so I'm way out of spec. I don't have a proper dial gauge, but I can get one if needed.

There are oversized journals available, I've seen them online. The thing I'm trying to figure out is it looks like the thrust surface on the crankshaft is... scored? In the video I think I'm showing the correct bearing, and the worn piece of metal I think is the side of the bearing? If so, then the thrust surface of my crankshaft should be the same (IE terribly beat up).

If I get the crankshaft turned, how would that help the thrust surface on the crankshaft? Is this where the buildup with hard chrome comes in?

 

Time for a rebuild or a replacement engine.

My recommendation is get the engine out, get it to a machine shop (or if you are technically inclined), and find out what is going to be needed to fix this engine then compare cost of repair to the cost of either a used low mileage engine or a new shortblock.

You could go with a new short block and have the head refreshed if the cost of a new engine is too significant.

These are the types of jobs that are a fun hobby, as long as you've got another car to drive in the meantime, nothing better than a job that in depth that ends with a happy running car in the end!

 

So. Follow up on this story. After much fighting, I pulled off my first partial engine rebuild! I only replaced the crankshaft bearings and did it without taking the head off.

I ended up lowering the engine to the ground, putting it on a hand-cart. put some wood between the side of the engine and the hand cart, and ratchet strapped the engine the the hand cart. I then laid the engine on it's side by tilting the hand cart. The boards were long enough the stuck out past the end of the hand-cart, so I was able to prop the engine up, and remove the hand cart. I then was able to remove the oil pan and do all the work. I put in a set of new set of bearings, and I found someone on craigslist in a nearby city that was selling mini parts, and they sold me a new crankshaft. Reassembled, and my mini is back on the road!

 

How long did it take you?