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Old 04-01-2003, 07:55 AM
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Join Date: Apr 2003
Location: Montreal
Posts: 102
Question 300D Engine swap


I have a clean rust-free 1979 300D with a tired low-compression engine. It barely starts anymore on cool mornings. While looking for a replacement engine, I was offered a rusted 1976 300D with a strong engine. These cars are of different bodystyles, and I was wondering if the 76 engine would fit in the 79 body. If so, are any modifications necessary, and is it worth the trouble? Old affordable diesels are hard to come by in Québec, and there are not many parts cars out there.


Denis Larsen

Added info. Concerning 123c's question about the compression test: Yes, I have done a compresssion test, and the results were between 160, 180 240, 200, and 260. From what I've been told this is too low for reliable starting.

Last edited by Lars; 04-01-2003 at 11:02 AM.
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Old 04-01-2003, 08:01 AM
Posts: n/a
I'm not sure, but I think the long blocks will interchange. Unless you can drive the engine and really know a lot about it, this is a gamble.

You would be much better served to take apart your engine, bore it and use oversize pistons, or even though it is not my first choice, sleeve the block back standard and reused the original pistons if upon close inspection they look good.

Good luck,
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Old 04-01-2003, 09:23 AM
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Have you had a compression test done?
My 1979 300CD had problems starting on cool mornings also, but I replaced the starter and it starts right up. You might want to think about replaceing the starter with the updated starter if your engine doesn't have low compression.
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Old 04-01-2003, 10:07 AM
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Join Date: Jan 2000
Location: PA
Posts: 5,440

I read about the updated starter here before. Just exactly what is it? How does one know when buying a new starter that he will get the updated one? Are rebuilt starters available that are the updated one?

BTW, I just had to ask, what is that in on your picture, Mr.P----??????

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Old 04-01-2003, 10:17 AM
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From what I have read, the updated starter has a better winding. The rebuilt starter that I bought from FastLane a few weeks ago was the updated starter. When I compared it to my old starter, the updated one weighed several more pounds. The old style starter is still avalible on FastLane, but I think it costs a little more. I am not sure if all starters are going to be the updated one, and most places won't know if they are selling the updated model. The best thing to do is just buy one from FastLane to make sure that it is one

The picture in my avitar is a snowman some drunk college students made last month. I was sitting around at my brothers apartment, and I saw it sitting out in the athletic field right behind the apartment complex.
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Old 04-01-2003, 01:26 PM
Old Deis
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If you can get the entire donor car I would think the swap would be doable. There are some things you will need to rework, like the throttle linkage, and it is possible the transmission from the 76 will need to go with the motor into the 79. With those and the old driveline, and other parts right there it can be done.
There are lots of parts that are different, but with enough time and with the old car there I would do it.
Pulling a five cylinder non turbo isn't that bad of a job. Takes about five hours for me to do it alone. Just save every part you remove and I would take some pictures of the underhood before starting. Helps to figure out the oddball lines and so on.
Good luck, and keep us posted.
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