hello,

Hoping someone can answer this prior to me tearing apart 2 running cars and finding out no it will not work.

I have a 72 280se 4.5 v8 that is a driver. As such, last 4 years i clocked about 50k on it and it is due for chain service etc. if i dig into the chains, ill likely pop heads freshen them up and basically turn this into a mini rebuild.

I so happen to run into a late 80's 560sel w/ the 5.6 v8. car is a runner but needs suspension work to pass inspection. As such, can own it for right price. The car complete does nothing for me, however, the engine does.

I wouldnt mind dropping the 5.6 down in the bay of my w108. I would think i need to use the later exhaust manifolds as i thought exhaust ports were different shape.

However, what about intakes? Ideally, would like to swap the 4.5's d-jet intake on it and keep my djet. down the road i will pillage a spare efi setup off my shelf of old race parts and "update" the efi system.

basically, my question is will the 5.6 drop in place of the 4.5 w/ me using my existing 4.5 trans/ fuel injection, intake/wiring/ distributor. pretty much use the long block of the 5.6 and exhaust manifolds.

if the 5.6 engine will work, any other mods i should look into?

Truth be told, if the 5.6 will fit, ill likely do chains on the ground and pop heads do a valve job before putting back in a car. This will be my after hours winter project so not like i need it done in a weekend.

thanks

Mike

Basic swap yes.

Transmission: Top two bolts require relocation by 10mm each, by slotting of the holes in the trans and intermediate plate.

Exhaust: The 560 crossover pipe is above the bell housing, check for firewall clearance. You are correct about exh. manifold bolt patterns.

Intake: Same bolt patterns, but 560 ports are larger.

Distributor: Install 560 dist. gear on D-jet dist. The distributor in the 560 is tilted farther forward, so the pitch angle on the gear teeth are sightly different.

thank you very much for the input. greatly appreciated.

now that im gung-ho on dropping the 5.6 in-- anything i can do to liven it up while on the ground? like say grab cams out of x engine, or any other little trick.

will likely gasket match intake/exhaust ports when i do valves.

1st time digging into a mercedes like this. More familiar w/ vw/audi stuff and know what to rob form what cars for cheap hop up/performance stuff. Yet im pretty damn green on these mercedes.

As you surely know the 560 is an aluminum block engine. Caution on removing cylinder heads; those engines have been known to have head bolt threads pull out on removal. The Shop Manuals detail a repair process that is essentially Helicoiling, however five bolt holes on each side are tilted 2deg. off of 90deg. to the deck. Mother Benz offered a jig for drilling all of the holes; apparently made of unobtainium, and priced accordingly.

The engine arms of the 4.5 will bolt on the 5.6. As such the engine with sit exactly in the same way as the 4.5. No mods needed.

For the transmission, it's a bit trickier: The pitch of the two bellhousings is different. As mentioned by Frank, the two top bolts are 8mm more inwards the V. With a bit of luck your 4.5 bellhousing is one of those that was designed to accommodate both bolt locations. But you will need to enlarge the holes in the intermediate flange. The other issue will be with the oil pan, as the trans is supposed to bolt on it on the 560. Here, you cold try to fit the 4.5 oil pan and the two brackets that link the intermediate flange to the block from the 4.5. All the oil pan fixing holes are not in the same locations, so you may have to do a bit of drilling or taping.

You could use the 560 trans.

The 4.5 intake will bolt on the 560 heads. However the diameter of the runners is slightly smaller (39mm instead of 41mm). You will also need to grind some material out of the plenum, in the front and in the rear right corner, You will also need to grind some material out of the block where the rear right angle of the plenum sits.

The W126 exhaust manifolds won't clear the w108 engine bay. You need to use some r107 560SL exhaust manifolds.

New to this.. can I expand on this thread?
ENGINE CONVERSION in my 1976 450SEL. Have had this car for 35 years, it is a highly tuned, very clean, performance sleeper with over 300k. I may have just spun a bearing....I may repair it BUT


Thinking of installing a 1986-1990 560 engine and trans in my 450SEL. I am very familiar with the 4.5 and somewhat familiar with the 5.6. I would like to keep it simple and primitive. I would be willing to tale a small performance hit by keeping it simple, but I don't want to compromise durability. Hence the following questions.


Can I use 4.5 exhaust manifolds on a 5.6? I have European manifolds.


Can I use the 4.5 intake and fuel injection system? My early K Jetronic works very well. I'd be happy with my old control pressure regulator for cold enrichment. How much performance diminution from using the 4.5 fuel distributor and nozzles? Simple alternatives, advice?


Linkages for the transmission would have to be improvised- any advice?


Can I use my 4.5 distributor and electronics? (? Just swapping distributor drive gear?) Perhaps recurve the distributor?


Will the 6cyl Delco AC compressor with bracket fit the 5.6?


TRANS
Will the driveshaft length have to be altered?


How can I work out a mechanical speedometer drive?


Are there any needed electronic controls on the trans?

I do not know the answers to most of your questions to be honest. I would guess that you are probably going to have to see what swaps over and not.
For the things I might be able to answer. I would say that you cannot use your intake and that is ok you can swap over the throttle linkage and make the 560 stuff work. You can also just swap over to a cable drive pedal assembly with fair ease.
You could use your 4.5 fuel distributor and injectors and stuff. I think you might have to tweek the lines a bit.
Transmission driveshaft will have to be altered. The 722.3 is definitely a different length.
Mechanical speedo is easy. Just remove the tailshaft housing and swap in a drive gear setup from a car with a mechanical speedo. 300e stuff will just drop right in.
I do not know for sure about the speed being correct though. My guess is it will be fairly close.
No electronics on trans is required. But there is WOT detent for downshift.

Hey thanks. Just to clarify:

You think 450 intake manifold will NOT work but could put my fuel distributor and injectors on the 560 manifold, along with my warm up regulator. I'd have to use 560 idle air valve and computer, abandon my aux air valve.

More on that... Only reason I'm looking to use my fuel distributor is because I assume I'd have to use the 560 ECU to run the EHA valve- I'd rather not- and I'd have no provision for cold enrichment. Happy to use 560 fuel distributor if there's some simple way to do enrichment. Any ideas?

A 560 gas pedal with cable- is that what your saying?

On the speedo drive, my 450 drive would fit into the 560 tail housing and have a driven gear off the tailshaft?

WOT- How does the 560 kickdown work? Not an electrical solenoid like 450? I thought 560 had the same switch under the gas pedal?

You've no clue on the exhaust ports- exh manifold compatibility?

Thanks this is a great help! More to come, I'm sure.
Kevin

This might not be accurate, depending on year and transmission style.
I recently read this and similar articles on other blogs, and it appears people copy the same information.
There is stories out there of crossover or dual pattern 722 transmissions, but I have never seen one, nor could I find any pictures of one on the internet.

I could only match 4 bolts, out of 12 in total, in addition too, you have have to machine a lot of the aluminum plate, to fit over the rear of the engine.

So swapping an aluminum 5.0 M117 in place of a cast iron 4.5 would involve also swapping in the transmission that came attached to the 5.0 as well.

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Have a look at this:

http://www.peachparts.com/shopforum/mercedes-benz-performance-paddock/321240-project-iron-block-5-6-a-13.html#post4252242