300SD Engine Swap: W123 300D possible?
 

Hi,

I've got a question. I've got a Mercedes 300SD from '82 with a broken piston, it's got a very bad compression on one cylinder. Rebuilding the engine will cost me a lot of money, and now i am looking for another engine. Is it possible to swap a W123 300D engine into the SD? If so, is a N/A 300d engine also possible or does it need to be a turbo engine? I.e. is it possible to install a N/A w123 300D engine in combination with the turbo from my 300SD?

Best regards,

Alex

You can swap a w123 617.952 engine into a w126. You'll need to exchange the Oil filter housing and engine mount arms. But I wouldn't use a 617.9xx N/A engine because it would be underpowered for a SD.

Only if you like a short engine lifespan.

A turbo 617 engine will swap either way between the 126 and the 123. there are some differences though. like the oil filter housing, motor mount arms will have to be exchanged. maybe a couple other things.

the SD uses an electric sender for the oil pressure gauge, and the 123 uses an oil line to the gauge.

the NA engine is a 5 cylinder also, but do not install a turbocharger on one. they are not designed for the pressures and stress. the turbo engine is beefier. A turbo can be put on but will shorten the life of the engine. then you will be right back where you are now, looking for an engine.

this question has come up before, do a search on it.

Charlie

Thanks for the replies guys! :)

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Is there any way of getting around changing the oil filter housing

Yes, just plumb in a manual oil pressure gauge and ignore the OE gauge in the SD.

Thank u can I get one ar any auto parts store

Do you have a W126 SD engine to install into a W123? and do you have the W123 617 engine from the 300D? If you do, then it is just a matter of removing 5 bolts and buying the gasket. also R&R the oil cooler lines.

I guess you can drill a hole and tap it for another gauge.

Enlighten us as to what you are doing, get us up to speed, and welcome to the forum. we can help you with enough info from you.

Charlie

No its the123 to 126

How is the swap coming along? post some pictures of your project.

a 123 to a 126 isn`t all that difficult. either way just a couple parts to swap over. swap over the 126 oil filter housing and you can keep on using the SD electric oil gauge. then there is nothing to buy.

Charlie

I have the engine in it is the turbocharged motor but I think im gonna have to get the oil filter housing anyways the existing one is hitting my steering. :-( how much is the other housing?. Other theen that it was easy. its ready to start once I hook up my glow plugs

A filter housing from the JY is around $25.

Charlie

Do you know if the housings are different much, had different in size

The difference is the rear plate where the high pressure turbo oil supply line connects and the difference with the SD having an electric sender for the gauge screwing in from the rear and the 300D an oil line on the side.

the rear plate on the 2 housing are different shape. the filter housings will bolt on the same to the engine.

Charlie