My W123 617.952 Engine Swap Thread - PeachParts Mercedes-Benz Forum

dieseldan44 · #1 06-27-2011, 08:58 AM

Hey everyone,

Engine swap from my parts car 1984 300D into 'Tex', the rust free 300D. Both engines are still in their respective vehicles.

The engine to be replaced actually still runs OK - doesn't start below 40F. Has a lot of blowby, and low compression (~220-240) on cylinders 4 and 5. Exterior of the engine is in good shape and will be used for parts.

Donor engine has 170K on the clock and has excellent compression (380) on all cylinders. Runs and starts like a dream. The donor car also still runs well, but is not street worthy due to poor brakes.

Few few questions as I begin my journey...

1.) The donor engine needs a general tune-up as it smokes (white) more than I'd like it to at idle. It probably also needs injectors and a timing adjustment. Should I do this before or after the swap?

2.) The donor engine is going to be on a stand for a while. It has 170K on the clock. What should I do to it while it is out? My goal is to put the time in now and do as much PM up front as I can.

My list thus far:

- turbo oil line
- oil cooler lines
- gasket between oil filter and block
- oil pan gasket (it's leaking)
- take of manifolds and clean
- possibly replace turbo

Any other engine swap advice much appreciated.

Thanks, more to come...
dd

aaa · #2 06-27-2011, 09:56 AM

I do my valve adjustments when the engine is out, definitely easier to sit on a stool next to the engine and do them, as opposed to leaning over the engine bay.

junqueyardjim · #3 06-27-2011, 10:03 AM

Since we know you will want this donor engine to be running at it's absolute best after the swap, why not do all the tune up work before you pull the engine. You say it has white smoke at idle. Better get rid of that. You don't smell antifreeze in that white smoke, do you? But you really want to get rid of that white smoke! But surely get the valves adjusted and check the timing chain and see that it is in spec and again I would recommend leaving all adjustments of the IP to a specialist unless you know exactly what you are doing. Another good reason in doing this maintenance now is that the engine is in a chassis and it will run. Do this or that, fire it up and be happy. It is difficult to run an engine on a garage floor, can be done, but it is nasty, dirty and noisy and it is difficult to tell if it is really building the power. Get it really running right, then pull it and do the changes you mentioned like gaskets, ect which really don't effect the running of the engine. Install your new gaskets, then clean it all up as much as possible, install it and you will be good to go, and happy that it started in an instant. Mine did, and I did it just last week. I put a 617 Turbo which was running wonderfully into a 240D 4 speed. Had a little trouble getting it fueled up, but once we had fuel, it started and runs like a champ and it is finished. I still have a bit of dissatisfaction with my shortened shift rods and fuel and temperature gauges are not reading, but those are little things to continue working on.

dieseldan44 · #4 06-27-2011, 12:14 PM

Thanks for the replies...

JJim:
Im sure the smoke is fuel related - no sweetness. I also used a 'block tester' and made sure there are no combustion gases in the coolant.

Getting it running well in the car it's in now seems like a good idea to me.

What else am i not thinking of that i need to plan for?

junqueyardjim · #5 06-27-2011, 12:36 PM

Well, my theory is do it now or do it later but don't mess with it much when it is out of the car. In case it won't start you won't know where to look.

Stretch · #6 06-27-2011, 12:41 PM

Quote:

Originally Posted by junqueyardjim

Since we know you will want this donor engine to be running at it's absolute best after the swap, why not do all the tune up work before you pull the engine. You say it has white smoke at idle. Better get rid of that. You don't smell antifreeze in that white smoke, do you? But you really want to get rid of that white smoke! But surely get the valves adjusted and check the timing chain and see that it is in spec ...

...Another good reason in doing this maintenance now is that the engine is in a chassis and it will run. Do this or that, fire it up and be happy. It is difficult to run an engine on a garage floor, can be done, but it is nasty, dirty and noisy and it is difficult to tell if it is really building the power. Get it really running right, then pull it and do the changes you mentioned like gaskets, ect which really don't effect the running of the engine. Install your new gaskets, then clean it all up as much as possible, install it and you will be good to go, and happy that it started in an instant. ...

I totally agree with Jim (well the bits I'm not 100% with I've removed!) Good advice.

If the engine is already running and you don't intend to rebuild then you are saving yourself lots of time and effort by checking it out now.

If I were you I'd also do a leak down test in addition to what Jim has said.

As for storing an engine once it is out:-

Firstly be warned things rarely (in my experience) go to plan. If you think the engine will be out and in storage for six months you should store it like it will be wrapped up for 2 years! Now I'm not trying to jinx the project but you never know how it will go. At the very least you need a dry safe place for the engine. Safe meaning out of the way where you won't be dropping stuff on it.

Consider buying an engine stand - or an extra engine stand.

I'd actually do an oil change before you pull the engine and store it. It sounds a bit daft but sometimes old oil contains corrosive contaminants.

Shiny bits on a stored engine could rust. Valve cover off => grease the cam shaft lobes or better still put engine builders' assembly oil over the valve gear. I'd also consider removing the rocker arms so that the valves are shut for the duration of the storage.

You will probably need to flush your cooling system - and possibly replace the thermostat (that thermostat housing is a pain in the arse to fix if the screws are corroded - much easier on an engine that is out) when you put the engine in the new car anyway...

Am I mad? Is this over the top? Only you can decide - it is after all your engine.

Good luck and swamp us with loads of nice photos.

dieseldan44 · #7 06-27-2011, 03:15 PM

Thanks Army - I was hoping you'd show up in the replies :-)

Fortunately I have a deadline associated with this - has to be done by the fall. So no long term storage. Going to get it running strong, pull it, put it on a stand and change the gaskets, turbo drain tube etc. Clean it and then put it in the car.

The 82 is going to have the front end and steering rebuilt at the same time - I figure removing the engine will make access that much easier :-)

Stretch · #8 06-27-2011, 03:23 PM

Quote:

Originally Posted by dieseldan44

...
The 82 is going to have the front end and steering rebuilt at the same time - I figure removing the engine will make access that much easier :-)

Oh wow what a difference it will make - I wish I'd done my front end when the engine was out. Particularly for a stubborn idler arm bushing...

The only thing you can't do is check the ride height and do the alignment - but once the engine is in it will be all systems go.

Are you planning a steering box reseal? I've nearly finished mine - including an alternative way of doing the adjustments as specified in the FSM. I'm searching for that new out of the box feel. If you're also doing the steering pump then I've got some tips for that too if it is one of the Vickers pumps.

Forgot to say:-

Engine paint? Take a look at the POR15 engine paint - I've done my block in black - it looks good at the moment. I don't know for how long it will stay that way though but it says on the can that they know what permanent means and that it won't burn off yada yada yada (we'll wait and see).

dieseldan44 · #9 06-27-2011, 03:50 PM

Quote:

Originally Posted by Army

Are you planning a steering box reseal?

Yes - or more accurately I was going to buy a rebuilt or low mileage unit. The future Mrs. only bone to pick with how the Mercedes drives is the sloppy feeling in the middle of the steering box on both cars. Id like to know what 'new' felt like...

How long did the reseal take? I don't want a science project! I have enough of them already...

Quote:

Originally Posted by Army

Engine paint? Take a look at the POR15 engine paint - I've done my block in black - it looks good at the moment. I don't know for how long it will stay that way though but it says on the can that they know what permanent means and that it won't burn off yada yada yada (we'll wait and see).

Yeah, I'll have to gauge my time for this...I wont have it totally apart like you did. Ill at least polish the valve cover but I may leave the rest. I can see this eating up a lot of time to do right.

sixto · #10 06-27-2011, 05:09 PM

How about a transmission reseal?

Is a coupe sway bar a performance upgrade?

Sixto
87 300D

dieseldan44 · #11 06-28-2011, 12:50 AM

sixto,

the trans in the donor is fine - im going to just flush the fluids and use that one. ive never resealed a trans before...let alone an MB one...so I feel like it could take me months to get it right.

jt20 · #12 06-28-2011, 01:50 AM

I would definitely replace the headgasket if it is original.

I would also plan on having the head rebuilt... I know it sounds excessive, but it will be worth it in the future. One good test is to wiggle the valves in the guides.
-set the crank to TDC
-remove the rocker arm set for the first piston
-remove the exhaust valve spring and retainer
-remove the valve stem seal
-wiggle

If you feel / or see any play... its time for a head rebuild. If you don't see any play, do this test on another piston. Rotate crank about 70 degrees and use the numbers on the valve cover to determine which piston as now at TDC.

Other than that... valve stem seals and front crank seal.

Stretch · #13 06-28-2011, 03:45 AM

Quote:

Originally Posted by dieseldan44

Yes - or more accurately I was going to buy a rebuilt or low mileage unit. The future Mrs. only bone to pick with how the Mercedes drives is the sloppy feeling in the middle of the steering box on both cars. Id like to know what 'new' felt like...

How long did the reseal take? I don't want a science project! I have enough of them already...

The steering box reseal is pretty straight forward - although I haven't finished it yet. Take a look at this link

http://www.davidpetryk.net/Mercedes/Steering.htm

It is considerably shorter than the two chapters on the FSM cd 46-220 part one and two!

I'm going for a new feel which is taking a bit longer. I'm getting a special tool made:-

W123 (300D) steering box - question about steering nut and working piston

I plan to replicate and condense the FSM procedure. This falls into your science project category.

dieseldan44 · #14 07-04-2011, 06:20 PM

So day #1 - as they say in the military ' no plan survives contact with the enemy'. Such is the case here.

Drained and refilled oil. Turned engine over by hand several times.

Re-installed the air cleaner box, 2 of the 3 mounts have been replaced by the ends of scrap work gloves by the PO. The exhaust pipe was taken by a forum member, and during that process the flex pipe broke about midway down. So no muffler.

Started up the engine off a half dead battery with 30 ft jumper cables. The motor flipped right over first crank no problem. Incredible.

I had forgotten - the motor mounts are s-h-o-t. Rattle my teeth at idle shot. So assessing true engine performance in this vehicle is going to be difficult with no exhaust and no motor mounts.

Curiously, the engine temp shot up, there was no water left in the reservoir.

So revised plan:

Task #1 - refill with coolant and check for leaks - identify leak source or assess if it could be something more serious. I checked the block using a block tester initially and it passed just fine.

Task #2 - wash engine in bay completely so that engine oil leaks can be further identified.

Task #3 - ???

Task #4 - Pull engine/trans and get it on a stand.

Questions:

How can I assess the turbocharger's performance in a pinch? I have a 1985 spare turbo on a shelf with no end play. The turbo in the donor car has some end play, but i dont know how much is OK. The turbo sounds fine, seems to act fine.

Considering the mounts are shot and exhaust is gone, what else can I do before I get it on the stand?

(jt20 - I dont want to do a full head rebuild now :-/ I feel like that may be to much of a risk at this stage)

dieseldan44 · #15 07-19-2011, 11:44 AM

donor engine out. see pics.

observations:

- if you want to pull a 617.952 out of a W123 with automatic attached, and dont want to damage the car body - you need a device to precisely angle the motor. we did not have that, and scraped the sway bar on the way up a bit (it was a junk body - so it didnt matter). for the reinstall into the car i care about i will need to rent a device to more precisely angle the lift

- the motor looks massive on the garage floor compared to the vehicle it goes into

- im a bit overwhelmed looking at it and knowing i still need to pull the motor from the dead car, work on this one, and then put it back in. its a project :-)

Task list of what to do next to follow.