Well, I'm in too deep to back out now.

After some searching for the cause of low oil pressure, and ruling out almost every other cause, my local (and trusted) mechanic advised me that my main bearings are worn and need replacing. After some thought and consideration, I had him do a compression and leakdown test, which confirmed my suspicions that one cylinder had pretty poor compression. His evaluation and opinion was that it's probably the piston rings, since he didn't hear anything to indicate the valves have any problems.

So, since I want to keep this car for another couple hundred thousand miles, and the rest of the car is in pretty good shape - brakes, electrical, interior, body (with the exception of the two rust spots on the front fenders), I decided to rebuild it.

I've got the service manuals, a pretty good tool kit, a fair bit of confidence and a lot of free time. So, out it comes.

Anyway, current status is this: the engine and transmission are out. Engine is mostly disassembled. Crankshaft is in the machine shop for polishing - micrometer says it's in good shape and won't need serious machining. The only thing left on the engine is removing the head from the block. I finally got my hands on the right 12-point head bolt socket, so this afternoon or tomorrow the head is coming off.

SO, for all you folks who've done this before:
Any hints or tips on things I should look out for? How about during re-assembly, any helpful advice?

I'll post some other threads about specific things that I'm thinking about, but any general advice would be appreciated.

Oh yeah, one more thing:
I'm doing this in a rented one-car garage in my apartment complex. Hee hee.

- Nathan
'83 240D, 255k miles, currently in a thousand pieces.
'00 New Beetle TDI, 25k miles (still all put together)

You are going to bore it and replace the pistons of course. Doing anything else would be a serious waste of a good rented garage.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Well, probably.

I'll have to see what the cylinder liners & rings look like, I guess.

- Nathan

Okay, so "probably" is now "yep."

Pulled off the head yesterday and pushed the pistons out. Let me just say that piston #1 came out in more than one piece.

Well, it's not THAT bad. The side of the piston wall, between the rings, just crumbled away around about 30% of the circumference. It's also got some brown scorch (or blow-by) staining on the side. #2 and #4 aren't in such good shape either, but at least they're still on one piece.

Cylinder walls don't look THAT bad, at least with a quick visual inspection. But, I guess I'll give it the whole job.

- Nathan
'83 240D, 255k miles
'00 New Beetle TDI, 27k miles

Do it right, Do it once.

All the more true if you plan to keep the car running for a couple hundred thousand more miles like you said.

It is important to try to find a machine shop in your area that has a *good* reputation with professionals. Do not go with the biggest yellow page ad or the 'low bidder'.

Regarding my machine shop:

My brother-in-law recommended him. Both of them are into drag racing, and this guy does all the machine work for their circle of friends/racers.

- Nathan

Nathan since I have been where you are at this moment, I can recommend a few things you should do. First you definitely need to replace the cylinder liners, they get all out of round over the course of time. New pistons are a call you make once you have them out and cleaned up.And I guess the biggest thing I learned when reassembling the engine was to make sure you have the timing chain threaded threw the block and on the crank gear before you button down the crank.


Joe

My 81 240D Baby

http://home.mebtel.net/~joeb/MB1.jpg