installing older engine in newer car - Page 3 - PeachParts Mercedes-Benz Forum

shadetreemechan · #31 01-11-2022, 04:55 PM

I was told it had R-12 in it. I will be going back with enviro-safe. I usually use PAG oil with it and its molecule is large enough the old hoses seem to work fine.
Thanks for the flush procedure. I will be putting in a new drier and possibly a new expansion valve. I need to get in the dash first and see what is in there.

shadetreemechan · #32 01-17-2022, 11:36 AM

Any ideas why I can drip time the pump fine at idle throttle, but can get zero fuel out of it at full throttle no matter what I do?

shadetreemechan · #33 01-17-2022, 02:14 PM

Nevermind. I got timing set.
FWIW, I saw somewhere on the interwebs a post that said drip timing was the same at no load and full load setting on the IP. I definitely found that to be FALSE.
The timing mark I made at no load is almost 1/8 inch different from the setting that works with the throttle at full load.
This engine is about ready to drop in, its about time to start cleaning the engine bay of the car.

shadetreemechan · #34 05-09-2022, 07:34 AM

I just finished a 1000 mile road trip with this car and realized I needed to update this thread.
The most important thing I learned in this project is that the throwout bearing for the early and late transmissions on the 240 are NOT interchangeable.
When reassembling, I gathered all the clutch parts I had and picked the best of the bunch to install. I didn't realize that the fingers that touch the clutch forks are not in the same location on the early and late throwout bearings. I put an early bearing in a late transmission.
The install went fine, but when I fired it up the first time and put it in gear the car would not move. I could hear the clutch disc touching the flywheel, but the incorrect throwout bearing was keeping the pressure plate from fully pressing the clutch against the flywheel.
There is nothing worse than installing an engine in the morning and having to drop the transmission in the same car that afternoon.
After that screwup, things went pretty smoothly. I changed all the orings in the AC system before charging it and recommend that everyone do that in these systems. Several of the orings were likely original and were in terrible shape.
Before taking off on this road trip, I had run 3 tanks of fuel through it to make sure it was roadworthy.
The car runs great and has good power. I cruised at 75 mph for hours at a time last week and it would cruise at 80, but it was loud. You really need a different rear end or a 300D to maintain speeds that fast for long. Trip average fuel economy was 29.6mpg.
I think I need to clean or change my oil separator. Cruising around town the motor burned no oil, but on the highway I burned almost a quart between fillips. I need to do some more research, but blowby is minimal so I don't think its a worn engine, particularly since it doesn't burn oil running around town.

shadetreemechan · #35 05-09-2022, 07:37 AM

If anyone has had similar experience with burning oil only on highway, please let me know what you did.
And a final thought, I MUCH prefer the 240 manual climate control over the automatic system in the 300s. I had never done a long trip in a 240 with working AC. Having the compressor cycle to maintain cabin temps is so much simpler than the monovalve setup. It does take some time to get used to feeling the engine load change all the time, but I like it.

t walgamuth · #36 05-09-2022, 10:18 AM

The faster you go the more oil you will consume.

vwnate1 · #37 05-09-2022, 11:33 AM

I'd suggest you're over speeding the engine a bit .

I too use oil whenever I drive 70 or faster .

No smoke, no drips, it just vanishes .

Not unusual for old tech engines .

barry12345 · #38 05-09-2022, 03:05 PM

At speed the 616 revs high compared to other versions of the 123s. The rings just do not seem to be nearly as effective.

A heavier weight oil will reduce it somewhat. New these cars where straight 40 weight I believe.

shadetreemechan · #39 05-09-2022, 10:48 PM

I run my tractors at the governor all day and don't have that issue. My teenage son runs his 1976 240 at 80+ every time he gets on the interstate and doesn't have this oil burning issue either and his blow by is much worse than this one.
I think its related to the oil separation unit. My guess is that the oil cant flow through it back to the pan at those RPMS so it goes directly into the intake.
I am going to take it apart and try to clean it.

vwnate1 · #40 05-10-2022, 10:16 AM

Be gentle with it ! .

I was fooling with one recently and it was very brittle and broke one of the hose nipples right off .

shadetreemechan · #41 05-10-2022, 10:18 PM

I have a spare one to play with, but the interwebs say its a cyclone inside not some sort of steel wool mesh that I had imagined it being. That makes my idea of it being the culprit less plausible.
I have to make this same 1000 mile trip in this car next month so I am gonna do something to see if I can change the consumption.
Its not likely I will get around to valve seals this month, so it may just be adding marvel mystery oil to see if its oil control rings.
This motor did sit for at least a decade, so valve seals and sticky rings both seem possible.

shadetreemechan · #42 07-09-2022, 10:17 AM

I repeated the same 1000 mile trip after 1000 miles with marvel mystery oil and a fresh oil change.
This time I burned one quart during the whole trip which seems much better. I can't say for sure it was the marvel mystery oil. I also discovered a gallon of rotella 10-30 on the shelf mixed with my supply of 15-40 when I did the oil change. I had forgotten that I bought a case of 10-30 last December when I thought I was headed to Niagra Falls for Christmas.

The rest of the case was missing so there is the distinct possibility that the first time I made this trip with the car I had accidentally put 10-30 weight oil in it. That might explain the excessive oil consumption as well.

flainn · #43 07-09-2022, 01:26 PM

One thing to be aware of is that it may be technically illegal in your jurisdiction to install an engine older than the car itself.

240D.Bill · #44 07-09-2022, 03:43 PM

Quote:

Originally Posted by shadetreemechan

I repeated the same 1000 mile trip after 1000 miles with marvel mystery oil and a fresh oil change.
This time I burned one quart during the whole trip which seems much better. I can't say for sure it was the marvel mystery oil. I also discovered a gallon of rotella 10-30 on the shelf mixed with my supply of 15-40 when I did the oil change. I had forgotten that I bought a case of 10-30 last December when I thought I was headed to Niagra Falls for Christmas.

The rest of the case was missing so there is the distinct possibility that the first time I made this trip with the car I had accidentally put 10-30 weight oil in it. That might explain the excessive oil consumption as well.

I did the same thing with my ‘73 240D partly because I was ignorant and partly because there was a case of 10w-30 i the trunk whenI bought it. There was more oil on the engine than in it. I just assumed a quart a day was the cost of owning an old diesel. Fortunately at the time you could always find a case of 10w-30 on sale for $5 and diesel was always cheaper than gasoline.

BillGrissom · #45 07-09-2022, 04:36 PM

Quote:

Originally Posted by shadetreemechan

I was told it had R-12 in it. I will be going back with enviro-safe. I usually use PAG oil with it and its molecule is large enough the old hoses seem to work fine. ..

Too late for O.P., but for anyone else doing so, I suggest PAO68 oil which works with all refrigerants and doesn't absorb moisture like PAG (forms corrosive acids). Durcool sells as their "Oil Chill" and claime more efficient. You can still buy AC mineral oil for use with R-12 or HC (Enviro-safe or Duracool). Don't use regular oil since AC oil should be low-wax. New hoses are "barrier", meaning they have an inner liner to limit leakage. You can buy on ebay. About time to re-rubber a 1980's car. Cutting and peeling off the collars to re-use the end fittings is the tough part.