1981 300cd NON turbo...Rare? - PeachParts Mercedes-Benz Forum

wstetson3 · #1 09-26-2015, 12:56 PM

I have an 81 Non turbo 300cd. It would seem that there was a small production run of 335 units in 81 until the change to the turbo.

I found this from 2005...

Club 81 car for sale 1981 300cd | Mercedes-Benz Club of America

Mine is silver/black. No evil servo to deal with. Is this something I should consider and possibly leave it original or should I proceed with the manual conversion? I HATE autos.

BWhitmore · #2 09-26-2015, 01:00 PM

From a value standpoint leave it stock. From a fun and performance value change to 4 speed.

uberwasser · #3 09-26-2015, 11:14 PM

Non-turbos might be rarer, but by their nature they are generally considered less valuable. Folks want the turbo. I don't think you'll find it ever valuable to the point of it being a collector car, unless it's currently in original near immaculate condition and you keep it that way.

wstetson3 · #4 09-27-2015, 08:20 AM

I would agree with you on the preference for the turbo. I have an 82 that I am going to use for parts and the engine has perfect compression, as does the non turbo. I have read that the manual transmission just seems to work better with the N/A cars. I don't know this first hand nor have I ever driven or even seen a 300 with a manual transmission. The 81 doesn't have rust so I opted to save that one. The 82 has cancer I don't want to deal with. I think I will save the engine and related components from the 82 in case the N/A engine ever goes.

I think the value may be an issue one day but a 4 speed coupe sounds fun so any value I lose will be offset by the fun that the 4 speed would offer. Now to buy the 240 parts car so I can get started on the conversion. I think the N/A would have enough power if it was mated to a manual gearbox.

cooljjay · #5 09-27-2015, 03:01 PM

Quote:

Originally Posted by wstetson3

I would agree with you on the preference for the turbo. I have an 82 that I am going to use for parts and the engine has perfect compression, as does the non turbo. I have read that the manual transmission just seems to work better with the N/A cars. I don't know this first hand nor have I ever driven or even seen a 300 with a manual transmission. The 81 doesn't have rust so I opted to save that one. The 82 has cancer I don't want to deal with. I think I will save the engine and related components from the 82 in case the N/A engine ever goes.

I think the value may be an issue one day but a 4 speed coupe sounds fun so any value I lose will be offset by the fun that the 4 speed would offer. Now to buy the 240 parts car so I can get started on the conversion. I think the N/A would have enough power if it was mated to a manual gearbox.

Turbo's suck...and its just another thing to break...Also it wears the engines out faster by forcing more air into the chambers...hints the need for extra oil squirters to cool things down...

Non turbo's are just as fast...maybe the 0-20 time varies on take off...but a well maintained non turbo is super fast...

Just a 4 speed manual by itself will not add any power to a non turbo...or to a turbo....When the 300D came from germany with the factory installed 4 speed....there was a 35lb flywheel, different geared rear end and a type M injection pump....Which great effected speed and horse power....

Just bolting on a 4 speed will do nothing for increased horse power....Specially if your planning on converting a 240 to a 300....There is so much more involved, from spring to fuel tanks....

Also a manual trans is HORRIBLE in traffic! I came from the bay area....sitting in bumper to bumper stop and go traffic....clutching in and out in and out and in and out....is horrible on the leg.....

Another thing to consider is the weight differences between a euro and us spec car....as well as all the smog crap(egr/alda/ada)....

There is just so much more research, reading and studying on these cars that one needs to do before moving into the mods department...

Its like the fad that was going on where everyone started putting their fryer grease in the fuel tank....

leathermang · #6 09-27-2015, 03:10 PM

Diesels and turbos are a ' made in heaven ' combo for mpg and efficiency... that is a physics truth...
Some manufacturer's do a better job of putting them together...
and the gearing has to match the use of the machine overall....
but turbos as compared superchargers.... are amazingly maintenance free and long lasting....

wstetson3 · #7 09-27-2015, 03:25 PM

I don't mind the clutch in traffic. I HATE autos. I'll shift myself anytime I have a choice.

As far as the power, these things are all slugs compared to most cars made today. I'm ok with that. I just like the old diesels.

I'm leaning toward the correct flywheel, assuming I can find one.

As far as grease in he car.... I would never consider killing one of these great cars. Opinions vary, but I think the conversions were/are a terrible idea. I'm sure I'll get blasted for that but those people sure did kill a lot of great engines.

I have read several articles that suggested the N/A engines did seem to last a little longer. I'll still keep the turbo engine on the stand in case I ever lose the N/A. I think these engines will get harder to find in the near future. The OM616 is getting harder to find already.

leathermang · #8 09-27-2015, 03:28 PM

Quote:

Originally Posted by wstetson3

.......I'm leaning toward the correct flywheel, assuming I can find one......

Worth the trouble and cost to find and use...

leathermang · #9 09-27-2015, 03:51 PM

Quote:

Originally Posted by cooljjay

Turbo's suck...and its just another thing to break...Also it wears the engines out faster by forcing more air into the chambers...hints the need for extra oil squirters to cool things down..

LOL.... your assumption that they wear out faster Completely IGNORES the fact that the bearings and lubrication system are upgraded for the turbo model.... and we are still only talking about a difference between 80 hp and 120 with turbo....

The advantage to the manual transmissions for these old cars is due to the cost of an auto trans being rebuilt.... IF you can find someone who can fix the auto trans....

toomany MBZ · #10 09-27-2015, 04:23 PM

Yeah, I'd like to see proof there are more turbo engine failures than non, percentage wise.

Technically, turbos blow.

leathermang · #11 09-27-2015, 04:28 PM

Quote:

Originally Posted by toomany MBZ

Yeah, I'd like to see proof there are more turbo engine failures than non, percentage wise.

Technically, turbos blow.

You will not find that with regard to our MB diesel engines.....
Ours were made by OCD German engineers who were historically far ahead of almost everyone else in metallurgy .....and engine design...

uberwasser · #12 09-27-2015, 04:55 PM

I've owned several non-turbos. Currently, I own both a turbo and non-turbo. I've maintained both equally. There's no way in hell the non-turbo is as fast. And that's even with the 2.88 gears in my '85.

That doesn't mean I dislike the non-turbo cars. I love driving mine. It has a different feel to it. But the power difference is unavoidable. The numbers just don't add up. 83hp/120lb-ft versus 125hp/180lb-ft in a car that weights the same isn't even close. And, in the end, most buyers want that extra power and don't care about the "collect-ability" of an uncommon non-turbo model. I think that's a rather plain reality, whether one likes it or not.

leathermang · #13 09-27-2015, 05:16 PM

" ***Want*** that ' extra' power".... LOL..... with the way On Ramps are designed many people NEED that ' extra power'.....just to safely merge with speeding drivers...

wstetson3 · #14 09-27-2015, 05:18 PM

That's why I posed the question about the rarity. You might be the one to ask about the gear ratios.

If I install a 4 speed in the N/A 300, would I be better served to leave the N/A rear end in the car or would the turbo rear end serve me better with the 4 speed?

I never claimed the N/A was as fast as the turbo, I did say I had read several articles suggesting the N/A cars have fewer failures. I don't have a study, just what I have read. It may or may not be true. Apparently some believe it to be true, some do not. I just remember reading something that was written by those who do. I read a lot about the N/A cars since that's what I will be fixing. I'm just trying to gather as much info as I can get before I start the conversion.

leathermang · #15 09-27-2015, 05:46 PM

" NA cars less failures" ... yes.... MB Diesels NA less failures... no...

You can not judge the rear end ratio based on what you have stated.... ' acceptable ' performance will need to take into account the specific ratios of the manual trans gear ratios mated with the power curve of the engine/turbo...

and I think the rear end ratio for the 300 NA is different from the 240 NA car.....if you used the 240 manual rear end I think your 300 would be wound pretty tight at cruising speeds....

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