installing older engine in newer car
 

I recently purchased an 83 240D with a window in its engine block. I pulled it and found that the #1 connecting rod had broken loose at the wrist pin and destroyed the block.
I have another 240 motor out of a 1978. We started it on the floor of the shop last week and it runs great, but i am hesitant to put it in to the newer car for a couple reasons.
1. The old motor has loop glow plugs. I am hoping I can simply replace them with the newer style pencil plugs and hook my existing factor fast glow relay to them. Are there issues with that idea?
2. I have read that there were horsepower upgrades that accompanied the addition of the egr and the head that accepts the smaller pencil glowplugs. This 240 body and interior are really nice, so I would hate to "depower" it with an older motor. They don't have many horsepower to spare.


I may be able to score a later model engine from a friend, but honestly the 1978 I have seems to be really low miles. It has almost no blowby and the camshaft lobes look like they just came off the assembly line.


I am not sure which route to go.

There are many items which differ between the older and newer engines. In addition to the glows the mounting for the AC is different, the oil filter possibly and other things. I'd probably not do it.

I'd look for a good used engine.....a prospect that gets less likely each year.

...another possibility is to buy a crashed 300 of the later variety and switch everything over.

The spare engine I have is an early 123 so it has the same ac mounting and oil filter. I was just out looking at it more closely. It looks like the thermostat housing is slightly different to accommodate a vacuum sensor on the newer one. There is also a tach sensor above the flywheel on the newer one which must be for the cruise control. I wonder if there is a magnet in the flywheel of the older one. I have never had a 240 with cruise control and am looking forward to having that work.
The throttle linkage is very different because the newer one has an egr and an oil separator. The newer one has a drain port in the top of the upper oil pan to accommodate the oil separator so I can't swap intake manifolds to make it work.
I actually have an 84 grey market 240 to look at for reference, but it is way different from both the 83 and the 78 with yet a third type of intake manifold, and no remote oil cooler.
I just took the quick coupler apart on my compression tester and found the bad oring that was causing it not to work. I may do a compression test on the 78 engine this morning to give me more data.

I do have a spare 617 turbo engine, but from what I have read its not a drop in conversion for a 4 speed 240. Haven't you done it?

I put a stick in a 300cd with turbo....an 82. In early 123 cars the ac is mounted high on the r side of the engine. Later cars from about 82 have it mounted low.

This motor I have with loop glow plugs and a 1978 casting number on the head has a delco r-4 mounted down low. It must have been the first year or some odd ball. I guess someone could also have swapped an older head on it, but it doesn't appear its ever been apart.
I hope I have found a solution. I picked up a 1982 motor today that was pulled from a pull a part by my neighbor in 2013. It is missing its injection pump, but turns over and doesn't look too worn from looking down the oil fill hole on the valve cover.
I will adjust the valves and do a compression test on it before making any decisions, but it is a carbon copy of what I pulled out of the car, so hopefully it is in decent shape.
It doesn't hurt anything to turn the motor without an ip on it does it?

I don't see how it could cause any problems. Rotate the engine a few turns by hand first, check that it has oil. IIRC that IP is pressure oiled, secure the hose before cranking.

Good luck!!!

If the turbo motor is a known good motor I'd think hard about using it.

@sugar Bear: good call on the oil line to IP I had not thought of that.
@ t walgamuth, I thought the transmission had to be shifted back, driveshaft shortened etc to get a 617 where a 616 had been.
Maybe I need to do more research, though the turbo motor is from a wagon and has only 150K on it so I have kinda been saving it for the right wagon.
My wife dropped on me last night that christmas involves a 2600 mile road trip, so focus will turn to my 84 wagon right now to make sure its ready. I may not mess with this 240 again until after Christmas.

yes the 300 engine requires a shorter front ds than the 240....cost maybe $200.

x2 on going from a 4cyl NA to a 5cyl turbo...w a 240D diff it will be nice.

Well, when I did it I swapped all the different parts over. Keeping the 369 diff will give you the capability of peeling out but will sing a song on the highway and use 20% more fuel.

Five cylinder into the 240D will require moving the transmission back by one cylinder's length, modifying the driveshaft by the same amount, and modifying the shift linkages. Diff swap to a 2.88 or 3.07 is optional, but I'd recommend it. I have a 300D with the manual from a 240D and it's worth the effort to have the turbo five cylinder with the manual transmission.

Looks Like Fun
 

I'm in to see how it all goes .

On a similar note, I just pulled the timing gear, intermediate shaft(nut version), bushings, bearings, countershaft, and thrust from my '78, and dry fit all the corresponding parts from a late version '83. They look radically different but fit up just fine. Oil passages were added to the front bearing and shaft to improve lubrication. The inside and outside diameters of the relevant bearing/bushings were also adjusted for the larger diameter of the late shaft which used a bolt to fasten the timing gear as opposed to the nut from the early model. I'm confident it will work and reassured by the FSM which states for repair purposes the late version can be used if and only if the entire set is replaced(gear, shafts, and bushings, and fasteners). I am keeping the early diaphragm pump.

I haven't messed with it further, but I am still leaning toward another 616. My 84 wagon is in the shop now, surrounded by 240 engines. My son was laughing in there the other day that even though he was surrounded by lots of engines, they collectively represented still a pretty small amount of horsepower. At 17 he finds how to squeeze every ounce of power out of his 240.

I think the 240 will remain a 240. The correct year engine I picked up for $200 built oil pressure and a compression test showed all cylinders between 320 and 345. Now comes cleanup and component swap.
I am a little tempted to pull the pan and inspect a rod bearing or two, but with those compression numbers it is probably fine. Can I pull a rod cap without removing the upper oil pan?

You'd probably find the '78 engine has more power from not being filled up with EGR gunk over the years. Whip some conversion pencil plugs in and away you go.

Wikipedia says they upped the power rating after 78 from 64 to 71 hp by changing the prechamber design and camshaft.

I hope they are correct. There was a lot of carbon built up under the injectors. I will probably delete the egr and give it an italian tune up.

I’m willing to bet that a worn out 71HP 616 will be FAR less hp than a tight 64HP 616…

I am not following you. I thought those compression # I posted for the 71hp were pretty good, Especially for a dead cold engine that definitely has not been started in more than a decade.

Do those numbers look worn out to you?

Reusing An Old Engine
 

Yes, I highly recommend removing the lower sump for cleaning, no I don't recommend undoing the road bearings .

As mentioned, replace the original series typ glow plugs with the parallel ones, clean and adjust every thing you can and motor away happily .

I now have an 82 motor to go in so glowplugs and everything else matches. I got it on the engine stand today and started checking it out more closely. It looks like it has only about 3 degrees of chain stretch according to the cam alignment notch method. I have a dial indicator so I am going to try to use the 2mm lift method and see what that shows, but between the lack of stretch and the good compression numbers I think this might be a pretty good engine.
Also I pulled the transmission off of it and the clutch disk is OEM and has a date code of March 1982 on it. Original clutch sounds like a low mileage engine as well.

YAY !
 

There are still quite a few low mileage originals out there but getting hard to find as those that have them, consider them 'junky old cars' and often junk them when in need of any repairs or failure to pass safety inspection .

Dial indicator confirmed 3 degrees of stretch so I have an offset key on the way.
Yes, I am fortunate to have a few neighbors interested in these old Mercedes. The motor I am putting in was pulled from a pull-a-part by a neighbor in 2013 and has been in his shop ever since. I am giving him $200 and a manual transmission from a 78 in exchange for this engine and transmission combo.
Anyone know why I am having a hard time sourcing a lower oil cooler hose? I have a spare set, but they are OEM ones that have been pulled from other cars. I would like to put new ones on this one, especially considering that it appears the lower hose on the blown engine may have failed causing the thrown rod.

OM616 & 617 Oil Cooler Hoses
 

M-B discontinued one of them, there's some really detailed threads on making up your own using full circle band typ clams and 15MM hose, the hose you use is critical as Diesel contaminated motor oil attacks, softens and ruins the wrong hose very quickly .

Maybe take your old hoses to "Hose Man" franchise shop ? . there are myriad custom hose makers, ask at any heavy duty truck or construction equipment shop, they'll know the best local place to go .

I found a URO brand lower hose on fleabay. I am not sure why they don't show one on here or the other partshauz on the web.
Today was cleanup day for the engine going in. My parts washer was too close to the overhead crane not to try this, and it worked pretty well to get the bulk of the grime off.

Shop Notes
 

When I had my Indie. VW Shop I had the wonderful Gray Mills solvent tank, I used to put bare long block VW engines in it......

Your shop image looks quite like that shop ~ it was jammed with spars and tools and always busy .

I miss it dearly .

I am going to reuse the r-4 compressor from the car, but have no idea what oil is in it. Can I just dump it out and put fresh in or do I need to do some type of flush on the compressor?
I have some ac flush I plan to use on the hoses, but it seems harsh to flush the compressor itself. Supposedly the PO had done several thousand $$ in AC work shortly before the motor let loose and the compressor looks pretty new.

Do you know what refrigerant the PO had used? R12, R134? The oils are not compatible with each other and are specific to the refrigerant used. See if any fitting adapters were used on the hoses to indicate whether it had been converted. If the same type is used and the oil otherwise looks fine, no need to flush. It would be recommended to drain and measure the quantity from the compressor and compare to spec. for filled, could be under/over and the right oil charge is important to overall lubrication and cooling efficiency.

If you need to flush the compressor, attach the old barrier hoses to it, fill the low side with flush, hand turn the compressor until it comes out the other end, repeat a few times and then give it a good blast of compressed air to clear.

If you are going with R134, make sure that your barrier hoses are compatible, R12 hoses will weep and loose R134 over time. Many new hoses are built to R134 standards and are compatible for use of R12. If you have a hard time sourcing, a hydraulic/hose shop will be able to rebuild your fittings with suitable hose.

Get a new filter drier as the system has been open for a while and perform a long vacuum on it to test for leaks and boil off any residual moisture in the evap/condenser when you are ready to refill.

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.

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?

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.

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.

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.

The faster you go the more oil you will consume.

240D Oil Consumption
 

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 .

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.

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.

Be gentle with it ! .

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

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.

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.

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.

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.

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.

Oil Useage & Piton Rings
 

I've forgotten if it smoked on accel, or decel but in either case I've done the soaking the pistons in MMO for a few days more than once and it really did help reduce blow by and crank case pressures, lowering the leaking significantly .

If you are aware of anyone claiming no oil use at high speeds with a 240d. Try using whatever oil they are using. Their multigrade may just be holding better viscosity than whatever you are using. When hot.

Manuals on most of our air cooled lawn tractors specify 10-30 for example. I use straight 30 or 40 weight oil. Some of our engines are really old now and still run as new. We are talking larger lawns. Plus 40 years of use.

You want to reduce oil consumption on a car using 10-30 to about half. Use straight 30 oil. In most cases it will reduce consumption that much.

Many old timers think using 10-30 in an older diesel engine will reduce the lifespan of that engine over time.

I failed to mention in my earlier post that I also changed oil brands, going from rotella to mobil one. My 83 240 uses very little oil on the interstate running 15-40 rotella.
I would not have ever used 10-30 in that car intentionally during the summer. I had bought it for a winter run up north. I have found switching to 10-30 in winter helps cold starts and mileage, but we don't get enough winter in TN to make it worth the switch.

I have the same oil issue running highway speeds for extended periods. On a 600 mile trip I probably burn about a quart. Nothing around town. I have an aftermarket provent catch can installed which catches quite a bit of oil -but again, only on 70mph+ extended trips.
As someone mentioned earlier, I think those are just the breaks for a 616.

Ditto for everything BillGrissom mentioned. I take it Envirosafe is a similar formulation to Duracool (which my system is running)? What a difference it makes over r134...

Good to know about the throwout bearing compatibility.