I've been gone a while, back on now.

Here's my tail of woe. Recently bought a really nice '79 300TD, pretty red paint, nice interior, ran like a dream, man the clock even keeps time. However, I soon noticed that the alternator belt wouldn't stay tight. Before long she spit the bottom pulleys off, along with the harmonic balancer, which is bolted to the end of the crank. The retaining pins (2) were sheared axially.

Bummer. I bought a new balancer, chased the threads out on the crankshaft, bought a new bolt (18mm), retaining pins, and spring washers (3). Lock tighted the threads and torqued the heck out of it. Didn't last a week, spit it right back off. Now the retaining pin recesses on the crank are wallowed out. Crank shaft is shot.

I'm faced with a very expensive crank replacement on an otherwise sound engine. Scrapping the car or parting out, or

Finding a certified used engine, at a very reasonable cost, paying shipment to Knox. TN, paying installation, which I've been quoted at $1,000 cash...American.

Any ideas?

Above all, when buying a non turbo 300, beware of loose belts. One heck of an expensive lesson.

Sell it for whatever and walk away. It apparently doesn't like you and will only cause pain and suffering!! Don't do as I did and become a slave to a krap kar!

Thats what I'm thinking, I may post some pictures, see what I can get, take my lumps and chalk it up to experience. Or I could park it in the living room and let the kids eat in it like that fire engine at Darrell's or something.

To add insult to injury, the Wife told me not to buy it. As usual I ignored her, so you know what I'm hearing now.

I have options for mine;
#1: Gut it and make a dirt tracker
#2: Sell or donate to a movie company that needs a car to trash
#3: Make a movie where I trash it
#4 Cut it in half and make one of those cute little car couches out of the rear end

Thats a bummer. I always think of hillbilly fixes on these cars. How about welding the old pulley or fabricating/welding an adapter onto the crank. It would'nt cost much to try. Probably need a professional welder though because of the crank steel.

Don't bother trying to weld it. My brother once owned a Mazda that had a worn crankshaft-nose which caused the pulley to wobble (this was a design flaw that showed up on late '80s Mazdas and the early Miatas as well). He had someone try to weld it and it only held for about a week - money wasted. He ended up buying a new crankshaft.

If the car is otherwise mint, just get a replacement engine. There are tonnes of these cars in junkyards, so I can't imagine it would be hard to get a used engine.

Good luck.

Greg
'84 300D

Do you have any idea what was causing the problem to begin with? It seems odd that the balancer would become loose to start with. Could the pulley have been bent which was putting odd pressures on the balancer? Any indication of other damage? It may be worth experimenting with a new (used) balancer assembly before giving up. My Mercedes manual states that on the 617 engine the vibration damper can be replaced without balancing and the balance plate can be static balanced. How badly damaged are the grooves for the dowel pins?

I thought I would also add the following: I read on another Mercedes board that the pulley and balancer can come loose if they are installed incorrectly. It is my understanding that these two parts can rotate as you crank down on the bolt, which damages the key rihgt then and there, with the result that everything comes loose again in the near future. What you are supposed to do is install them a little off to the left, so that when you tighten the bolt they rotate slightly to the right and fall into place with the key and slotj. Otherwise the pulley and balancer try to rotate and end up putting a lot of stress on the keys. In any event, you have to watch as you tighten to makesure the balancer isn't turning (and in turn damaging the key) as you are tightening the bolt.

Someone please correct me if I explained this wrong. I just remember reading something about this a long time ago and wanted to make the point as best I could. I have never actually done this job, so I can't give any other advice besides hearsay.

Good luck.

Greg
'84 300D

DO NOT tell wife (or that it's a minor repair), pay whatever you must to fix it, or tell her you found a better deal and are going to sell this to get that. No matter what, admitt NOTHING!!! they can smell fear and guilt a mile away...

__________________
1985 190D 2.2l Sold-to Brother-in-law
1996 Mustang 3.8l -"thinks it's a sports car"
1988 Grand Wagoneer - Sold (good home)
1995 Grand Cherokee Ltd -"What was I thinking??!!"

I may still have a good crank if you are interested...I'd have to look to be sure.

If somehow the wrong belt is in there, that could be causing/contributing to the problem. Worth at least checking out.

I have a vibrating engine that needed a turbo and head overhaul..but before that my damper came off twice!!!The first time I went by MB's method. The second time my mechanic drilled 2 extra dowels holes into the crank...just slightly larger than the old holes and used tapered roller bearings to tighten it up...redrilling the old holes. That was 10K ago and right now it is tight. I talked to the machine shop foreman at my local CAT dealer, he has used titanium paste to repair cranks on large CAT engines and says it works great. Hardest stuff he has ever scene. If I have another problem..that's my cure. Tell the wife it's fine....just needs a little work. I would not give up...yet.

Chapp

__________________
1983 300SD 343K everyday car
1983 300SD 285K from junk yard-tooks parts from deer car- runs great. Brothers car.
1984 300SD parts car-Hit deer
1979 300D 175K non-turbo "Doctor"
1979 300d parts car

I have a '83 300D that had the same dampener flinging syndrome. I ended up getting a rebuilt engine for around $1600.
Not sure if it is worth it in a non-turbo. ( might be less $$ though )

Something is out of whack, and the time that you are most likely going to spend hunting for it, and fixing it will be close to the cost of a rebuilt.

Good luck!

-Larry

__________________
It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D

I would sure have it towed to a good auto machine shop and have them drill and set larger pins and reinstall dampener........
William Rogers

I assume the crank shaft would have to be removed for this to be done, which means pulling the engine. This is where the expense comes in.

I can probably replace the engine for less, if I can find a reasonably priced one in good condition.