classic car forum header
Classic cars forum & vehicle restoration.
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
Register     Posting Photographs     Privacy     F/book OCC Facebook     OCC on Patreon

1971 Mercedes W108 280SE conversion to diesel daily driver
Goto page 1, 2  Next
Post new topic   Reply to topic    Classic cars forum & vehicle restoration. Forum Index -> All our old cars, vans, lorries etc
Author Message
pryantcc



Joined: 07 Sep 2009
Posts: 88

PostPosted: Fri Aug 29, 2014 11:18 pm    Post subject: 1971 Mercedes W108 280SE conversion to diesel daily driver Reply with quote

Hello! Is anyone interested in reading about the conversion I'm undertaking? Replacing the original 3.5 V8 petrol engine and 4 speed auto with a 1999 Mercedes OM606 turbodiesel and 2003 6 speed Merc manual gerabox.

Maybe you're reading about it already elsewhere on the interweb!!

Back to top
View user's profile Send private message
norustplease



Joined: 11 Apr 2011
Posts: 779
Location: Lancashire

PostPosted: Sat Aug 30, 2014 9:48 am    Post subject: Reply with quote

Sounds like a challenge. A good way of making a nice car more economical to drive, and more usable.
_________________
1953 Citroen Traction
1964 Volvo PV544
1957 Austin A55 Mk 1
Boring Tucson SUV
Back to top
View user's profile Send private message
Rick
Site Admin


Joined: 27 Apr 2005
Posts: 22429
Location: UK

PostPosted: Mon Sep 01, 2014 12:23 pm    Post subject: Reply with quote

Indeed, it'll be an interesting build to follow so post away Smile

RJ
_________________
Rick - Admin
Home:https://www.oldclassiccar.co.uk
Videos:https://www.youtube.com/user/oldclassiccarRJ/videos
OCC & classic car merchandise (Austin, Ford ++):
https://www.redbubble.com/people/OldClassicCar/shop
Back to top
View user's profile Send private message
pryantcc



Joined: 07 Sep 2009
Posts: 88

PostPosted: Mon Sep 01, 2014 12:33 pm    Post subject: Reply with quote

That's certainly my plan, to have something which looks well, is reliable and reasonably cheap to run.

I started this project almost a year ago now and am currently at the point where the mechanical work is well underway.

You can see the front suspension is just about absent in the pic below. I took it all apart for refurbishment as a wheel bearing was gone and the further I stripped, the more worn out stuff I found!

The passenger door is not closed, the alignment is actually pretty good! The paint is pretty fresh, but bubbling through from underneath, so will need doing again.


Here's a close-up trying to show the bubbling above and below the trim strip. This is the worst patch for size, but I have issues on almost every panel. Around the rear screen is the worst I can see externally.



This is the inside of the passenger door. In their wisdom, someone blocked up the factory drain holes with filler and drilled new ones which weren't at the lowest point of the door!


The whole underside was sprayed with Schutz prior to sale. I've scraped off a couple of the rusty patches here, no surprises, I could see they were there before I bought it. It's mostly just surface rust which I'll blast off and re-paint.


The front screen has moisture damage also, so I'm a bit afraid of what I might find in terms of metal when I remove the windscreen rubbers!
Back to top
View user's profile Send private message
pryantcc



Joined: 07 Sep 2009
Posts: 88

PostPosted: Fri Sep 05, 2014 1:24 pm    Post subject: Reply with quote

So, front suspension was removed, blasted and primed where required and new bushes/bearings, etc fitted.

This was the rustiest bit, some corrosion worth stopping.


Springs and brake backing plates were scruffy looking too. Turned out both backing plates had stress fractures, so were welded up before re-fitting.



I only blasted the spring turrets on the subframe as I was afraid I'd have to chop up the middle of it to make the new engine fit. It was in good nick in the middle anyway.


Back to top
View user's profile Send private message
pryantcc



Joined: 07 Sep 2009
Posts: 88

PostPosted: Tue Sep 30, 2014 2:07 pm    Post subject: Reply with quote

Here's the front subframe being built back up:


When I got the subframe back onto the car, I had some trouble refitting the springs due to access restrictions for the spring compressors. I ended up using just 1 spring compressor fitted inside the spring. When I was ready to connect the kingpin, I discovered this major alignment problem on the passenger side:



So, I took it all apart and out of the car again to try and discover what exactly was bent, or if I'd put a right-side component onto the left side, or some other similarly stupid thing. I started by swapping bits from one side to the other. When I finally swapped the upper wishbone thingy from the drivers side to the passenger side, the alignment was perfect. When I put the passenger one on the driver's side, it was misaligned. Conclusion: The passenger side one was bent. Some gratuitous levering with a fence post and I managed to make it all line up nicely before re-attaching to the car, adding the stub axle and connecting everything up.
Back to top
View user's profile Send private message
norustplease



Joined: 11 Apr 2011
Posts: 779
Location: Lancashire

PostPosted: Fri Oct 03, 2014 10:25 pm    Post subject: Reply with quote

You are getting on nicely. Have you many alterations to make to fit the new diesel engine?
_________________
1953 Citroen Traction
1964 Volvo PV544
1957 Austin A55 Mk 1
Boring Tucson SUV
Back to top
View user's profile Send private message
pryantcc



Joined: 07 Sep 2009
Posts: 88

PostPosted: Mon Oct 06, 2014 11:02 am    Post subject: Reply with quote

norustplease wrote:
You are getting on nicely. Have you many alterations to make to fit the new diesel engine?


Thanks! Nothing too serious in terms of the car. The change to manual gearbox is more invasive. The engine only needs simple new mounts, wiring and plumbing. No chopping of the engine bay required. It's really quite impressive how well the engine fits. The sump is just the right shape to avoid the large front cross-member. Engine height is tight but manageable. the engine itself needs a new flywheel/clutch setup.

For the gearbox, I have to make some transmission tunnel modifications for the shifter mechanism, modify the prop shaft, add a clutch pedal and hydraulic system.

All manageable really. It's a shame the W108 Merc is becoming expensive really as it's an easy enough conversion to make. (So far!)
Back to top
View user's profile Send private message
norustplease



Joined: 11 Apr 2011
Posts: 779
Location: Lancashire

PostPosted: Sat Oct 18, 2014 12:26 pm    Post subject: Reply with quote

Yes, I've only done this to a car a couple of times in the past. In my experience what takes the time is things like throttle linkages and electrics, which never quite suit the new application.
_________________
1953 Citroen Traction
1964 Volvo PV544
1957 Austin A55 Mk 1
Boring Tucson SUV
Back to top
View user's profile Send private message
pryantcc



Joined: 07 Sep 2009
Posts: 88

PostPosted: Wed Oct 22, 2014 4:50 pm    Post subject: Reply with quote

Work proceding on stripping the donor vehicle. It was slow and painstaking, but worked out OK by following a methodical approach. It didn't help that I was paranoid and being super-careful about tracing and labelling every cable. The wiring was my biggest worry really, but also an aspect I'm reasonably comfortable with. My approach was to expose all the cables first and then to disconnect things one by one and check each time if the car would still start. At this point the immobiliser function on my ECU had already been disabled.

Sorry about the photo quality. The donor car:


Here's the power plant. It's had some boy-racer treatment to the top cover, but doesn't seem to have suffered badly, still runs sweetly and very cleanly.


Some more shots of the wiring reverse-engineering!

This spaghetti is mainly the old instrument cluster connections (I hope to find a tacho and glow plug indicator light in there) and the computer diagnostic port connection.


On the other side of the donor engine bay is another box of tricks, power for the ECU comes from here and some other stuff.


It turns out I didn't need anything from in here and could have left the dash intact, but I needed to get in there to trace some wires in order to learn this! I'll know for the next one Wink


So, this is it with all the required electronics sitting on top of the engine. Attention now moved to the mechanical strip down!
Back to top
View user's profile Send private message
norustplease



Joined: 11 Apr 2011
Posts: 779
Location: Lancashire

PostPosted: Thu Oct 23, 2014 1:38 pm    Post subject: Reply with quote

Reminds me of the contents of one of those roadside telecoms cabinets that you sometimes see the BT man puzzling over.

Its coming on though.
_________________
1953 Citroen Traction
1964 Volvo PV544
1957 Austin A55 Mk 1
Boring Tucson SUV
Back to top
View user's profile Send private message
Rick
Site Admin


Joined: 27 Apr 2005
Posts: 22429
Location: UK

PostPosted: Thu Oct 23, 2014 3:41 pm    Post subject: Reply with quote

Interesting project, I'm not sure I'd ever get my head around integrating all the modern bits n bobs, wiring- and gizmo-wise, into an older car, so I doth my cap accordingly Smile

RJ
_________________
Rick - Admin
Home:https://www.oldclassiccar.co.uk
Videos:https://www.youtube.com/user/oldclassiccarRJ/videos
OCC & classic car merchandise (Austin, Ford ++):
https://www.redbubble.com/people/OldClassicCar/shop
Back to top
View user's profile Send private message
ka



Joined: 03 Dec 2007
Posts: 600
Location: Orkney.

PostPosted: Sun Oct 26, 2014 7:38 am    Post subject: Reply with quote

I remember the old days, where if a diesel engine had fuel, it would always run, looking at the knitting of a modernish diesel, you need to be an electrician, as well as a mechanic.
We had a friend who in the past ran his citroen on heating oil, a lot cheaper than diesel, and yes not quite legal, but we all did, and witnessed not quite legal actions didn't we?
Modern has a canbus system, I leave that well alone.
_________________
KA

Better three than four.
Back to top
View user's profile Send private message
norustplease



Joined: 11 Apr 2011
Posts: 779
Location: Lancashire

PostPosted: Mon Oct 27, 2014 3:32 pm    Post subject: Reply with quote

I must admit that an LPG conversion would be my first point of call for a cheaper fuel option on a large petrol motor.
But as Rick says, I take off my hat to this particular conversion project.
_________________
1953 Citroen Traction
1964 Volvo PV544
1957 Austin A55 Mk 1
Boring Tucson SUV
Back to top
View user's profile Send private message
pryantcc



Joined: 07 Sep 2009
Posts: 88

PostPosted: Thu Nov 06, 2014 10:58 am    Post subject: Reply with quote

Thanks for your interest guys. It's really much more simple than it looks in terms of electronics. Once the immobiliser/security aspect of the ECU was done away with ( this is black-magic to me too, but successfully achieved by a man who knows how) It really is only a case of providing 12V to the correct wires on the ECU. The remaining engine electronics (injector pump, MAP sensor, MAF sensor, throttle position sensor, waste-gate solenoid and glow plug relay) are all just a case of shortening wires to make it neat looking.
This engine will run perfectly if the electronic fuel injection pump is replaced with a suitable mechanical one from an older version of the same engine. However, these pumps are highly saught after and accordingly expensive, so I thought I try to keep the electronics going for now.
The CAN bus has been completely eradicated as there's no more communication needed between engine/gearbox/ignition key. All the remaining sensors report via voltage and resistance rather than via digital signals.

On the LPG front, my plan was always to put a lot of miles on this car, so I didn't want to put any money into a 40 year old engine which, in case of failures, would be expensive to get parts for. The easily available modern diesel (I can buy whole donor cars here for 500 Euro!) made good sense on that front. It can also burn chip fat if times get really hard!

The problem with heating oil, ka, is that it doesn't have the same lubricating properties as diesel, so the fuel injection system tends to wear out, or so I have been told!
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    Classic cars forum & vehicle restoration. Forum Index -> All our old cars, vans, lorries etc All times are GMT + 1 Hour
Goto page 1, 2  Next
Page 1 of 2

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
OCC Merch link
Forum T&C


php BB powered © php BB Grp.