Engine Gearbox transplant on 450sEL

[450SEL1979]

I have the opportunity of transplanting the engine and gearbox out of a 1977 450SEL into my 1975 SEL . The 77 model was picked up for parts by my regular mechanic interior reasonable , exterior (paint) is terrible clear nearly all gone leaving faded mid green paint. Surprise was it runs really well just 150,000ks
Versus my 1975 with 338,000ks on the clock
Took it for a run with mechanics trade plates attached, very smooth gear change
Plenty of power , no smoke on hard acceleration.

I am tempted to take up the option of giving my beast a 190,000 k freshen up

Anyone done something similar
Benefits of a 77 engine gearbox combo over an early 75 ?
What is a good used engine gear box combo worth ?

 

[Styria]

You may have some problems with this conversion. There are probably others on TK better qualified to advise than myself. I do think, however, that you're attempting to fit a D-Jet engine unit to a K-Jet engined car, and there could well be some issues with fuel and ignition (wiring). Sorry that I cannot be any more specific than that. Regards Styria

 

[450SEL1979]

If we go for a complete transplant ie: everything forward of the firewall
Electricals included that may help . I will then be looking for somewhere to store the 77 450sel. My engine gearbox combo is still ok
Just not as smooth as the 150k 1977
An extra couple of years and 190,000 Kim's will do that

 

[Styria]

I guess anything is possible iof you're determined enough. If you do go ahead, Brendon, you may wish to take some photos and hopefully post them on our website. Good luck with whatever you decide. Regards Styria

 

[450SEL1979]

Yes it would be a pity to see what I view as a low km 450SEL get scrapped just because of a paint job. Hence tne idea of taking the engine and gearbox out and putting them in my car.As at 338k mine is starting to show here age.
I have had engine transplants done in other cars in the past without too many issues.
However if doing so on a Merc is a real hassle I may pass on the idea and persist with my existing setup.
Although dropping a low km engine in to the beast is an appealing idea

Hence the original question
Anyone done it ???
What is a 150,000 km engine and gearbox (plus all associated bolt ons) worth ?

As I would love to freshen up my car and keep it a few more years
It is a daily driver BTW , approx 25k per year

 

[SEL_69L]

Just make sure that the '77 has a proven maintenance record to show the 150 k's. are true.

 

[Oversize]

I'd do compressions on both first. As Styria said the main issue you may face is the wiring. If the injection ECU is integral with the main looms up under the dash, it'll be a headache. You may not want to tackle the job if you have to remove the whole dash!!

It might pay to get the wiring diagrams for both and consult an auto elec. They may even wish to view the car/s.

The rest of it should be straightforward as you have all the parts available and they're relatively accessible (pump, filter, pipe and hoses etc).

Given the fact you can buy a whole (tired) W116 for $500, better ones for $1.5K and nice-ish ones around $3K, the engine/trans as stand-alone items aren't worth much. Source these parts from a MB wrecker and they'll charge you what you'd pay for a whole car on E-bay....

 

[Tony66_au]

Wreckers are not a fair value comparison though.

So a 77 K jet engine into a possibly 75 D jet car? or are they both K jet?

A visual will confirm as they are a markedly different engine so even a pic of your 75 engine bay will confirm.

Personally id be doing timing chains on the replacement engine as a matter of course so you KNOW its done and with the engine out it shouldn't take long.

The only hitch is you are replacing a know quantity with an unknown quantity unless the donor car comes with excellent provenance such as the car was bought from a client of your mechanic and he has known the car for years etc etc.

Id also think of perhaps doing a few mods to the engine before it is fitted such as extractors etc.

Good luck, piccies and a thread if you please!

Tony

 

[450SEL1979]

Thank Tony
Good questions
History of 1977 engine is limited to log books stamped to `100K or so
Nothing else, plus test drive of car with engine still in it. Went well , smooth
plenty of pickup and No Smoke

However your comments re modifications - extractors etc
Has me thinking , my other option is stilck with my more known quantity
my 1975 engine with 330K on the clock. Do some work on that

What i am after is a smoother performance , without the low rev issues i have at the moment. Which i did an earlier post on - stalling under heavy braking - currently surging up to 1000 rpm then back to 500 then up to 1000 again etc When sitting at the lights with foot on the brake


So this raises the question

What can be done to improve performace on a 1975 450 SEL - D jet ??


As i may be better off spending my $$$ on my more existing car setup

Suggestions anyone ??

 

[Oversize]

Hunting was a common problem, but I don't know if I was ever privvy to the answer. Could it be the trigger points in the distributor???? Perhaps the idle bipass valve or choke slide is floating loose?

I think I posted a thread about 6.9 performance modifications a while ago and I believe most of it would apply to the smaller engines of the era.

Firstly make sure your's has good compression and the timing chain's ok. Then check your fuel supply, injectors and tune.

Then I'd look at:

cold air intake,
exhaust (extractors, larger pipes and high flow mufflers),
engine fan (replace with electric fans), and
throttle body (go larger).

Obviously you can do much more, but the costs will rise.

Fortunately on a pre 1976 car in Victoria you can go nuts, as long as it doesn't make excessive noise, or blow more than 10s of continuous smoke.

 

[Oversize]

Here's the thread:

http://www.topklasse.org/forums/showthread.php?t=2426&highlight=performance+modifications

 

[Michel]

Yes it would be a pity to see what I view as a low km 450SEL get scrapped just because of a paint job.

If the donor car is so go and just needs a paint job, then why don't you keep the donor car as an everyday transport?

Give it a paint job and you'd be better off.

I can organise a reasonable paint job at the right price...

 

[Tony66_au]

Thank Tony
Good questions
History of 1977 engine is limited to log books stamped to `100K or so
Nothing else, plus test drive of car with engine still in it. Went well , smooth
plenty of pickup and No Smoke

However your comments re modifications - extractors etc
Has me thinking , my other option is stilck with my more known quantity
my 1975 engine with 330K on the clock. Do some work on that

What i am after is a smoother performance , without the low rev issues i have at the moment. Which i did an earlier post on - stalling under heavy braking - currently surging up to 1000 rpm then back to 500 then up to 1000 again etc When sitting at the lights with foot on the brake


So this raises the question

What can be done to improve performace on a 1975 450 SEL - D jet ??


As i may be better off spending my $$$ on my more existing car setup

Suggestions anyone ??

Michel has a good point re the donor car and its something I have done on a few occasions.

That said D jet cars in reasonable condition are usually a bit more spritely than K jet cars due to their lack of smog gear but if the Donor car is a D jet then its a fairly viable proposition, Keep your car for bits and drive the Donor car.

Extractors and a better exhaust will make a reasonable difference to performance and if the donor car has no issues it makes a fairly instant driver.

Other than exhaust keep the car in good tune and run a 95/98/100 octane fuel and perhaps a good quality air filter.

I also found that fresh fuel filter, a new set of genuine leads and good plugs make a difference as well especially when it came to smoothness as all of these items cause niggly non specific issues when neglected.

Id also check the in tank screen filter.

Cheers,
Tony

 

[Oversize]

If the fuel in the tank is more than 3 months old, drain it and use it for your mower!!!!

I agree with Tony and Michel and a new paint job means you can choose whatever colour takes your fancy!!

 

[Tony66_au]

Change the colour and it usually costs more..................

 

[450SEL1979]

New paint job suggestion from Michel has me thinking
Approx how much are we talking about $$$$??

I have complete set of rubber seals still in the box from a previous 450SEL

Re Fuel suggestion -I normally run my 1975 D Jet car on 98 premium unleaded

Car does approx 70km per day M-F plus approx 100 -120km on Weekend

Recent work last few weeks includes
New distributor cap (old one had crack)
Set of leads
New plugs
New fuel filter
Replaced cold start injector
Replaced air filter


Scheduled for next week
Refurbish brake booster (told it needs to be sent away)
While it in the workshop -probably new suspension bushes

Have set idle at around 900 for the moment
Today car ran very well with little of the surging erratic idle when foot on the brake at the lights. Also reduction in cut out on full steering lock when reversing into parking spots etc.

However tomorrow no doubt it will play up again

Re Comment - Buy the 1977 K give it a paint job use as a daily driver
Has crossed my mind however I live in Alexandria , park my car and my wife's car on the street ...joys of inner city terraces and postage stamp size yards

Though considering my 23-25,000km per year sharing the load may be an idea
worth thinking about

My 1975 SEL had done 305'000ks in 36 years until I got it an added 25,000 in 1 year. So 400,000 will come fast

 

[Michel]

New paint job suggestion from Michel has me thinking
Approx how much are we talking about $$$$??

Depends on the car, colour and what else has to be done before painting (dints, rust to be cut out, etc)

But anything from $3,500 (for a quickie-no colour change) to.... well the sky is almost the limit...

 

[WiSeGuYY]

LOL@ MICHEL , agree completely sky is almost the limit.

REGARDS

TAREK

 

[450SEL1979]

Having explored the options KJet engine into a D jet car. Looking like less of an option. Mechanic ( who I have dealt with for all service needs for 20 years) agrees. Looking at options of hanging onto the low km 1977 car for parts.
Problem is nowhere to put it. After storing another of my projects ( a 1979 Daimler VanDen Plas DoubleSix ) in a mates carport for 3 years
I have probably used up my car storage brownie points

As a previous post mentioned parts cars can still be had fairly cheaply
Though a pity to see the 77 get punted just because clear coat had all come off

As it drives very smoothly

I would post photos , but can't work out how to do it

 

[Tony66_au]

Ahhh yes the old "hide the car at a mates place" schtick!

Must be a good mate lol

By the way, for the uninitiated..... a 1979 Daimler VanDen Plas DoubleSix is a really nice version of a Series II V12 Jag.