W108 Mercedes 280SE diesel conversion project

Post pictures and stories about your cars both present and past. Also post up "blogs" on your restoration projects - the more pictures the better! Note: blog-type threads often get few replies, but are often read by many members, and provide interest and motivation to other enthusiasts so don't be disappointed if you don't get many replies.
Message
Author
3xpendable
Posts: 695
Joined: Tue Apr 12, 2011 8:03 am

Re: W108 Mercedes 280SE diesel conversion project

#91 Post by 3xpendable » Wed Dec 03, 2014 11:28 am

rich. wrote:i used super carlos fandango diesel in several motors.. less mpg than the supermarket stuff..as for young idiots, when i had my celica gt4 i could only get 17mpg where wifey would get 35mpg :D we got rid of that before we lost our licences :lol:
I hear ya, I got rid of my GT4 for the same reason!
Currently classic-less.

User avatar
TerryG
Posts: 6750
Joined: Wed Jan 05, 2011 1:54 pm
Location: East Midlands

Re: W108 Mercedes 280SE diesel conversion project

#92 Post by TerryG » Wed Dec 03, 2014 11:37 am

Think yourself lucky that your toy gets 17mpg. mine doesn't get that much if I drive like a nun!
Understeer: when you hit the wall with the front of the car.
Oversteer: when you hit the wall with the back of the car.
Horsepower: how fast you hit the wall.
Torque: how far you take the wall with you.

rich.
Posts: 6789
Joined: Wed Jan 05, 2011 9:18 pm

Re: W108 Mercedes 280SE diesel conversion project

#93 Post by rich. » Wed Dec 03, 2014 9:37 pm

when i had my rover sd1s i could hardly get more than 3 mpg... :D :D :D that was when people could afford petrol

cdodgyd
Posts: 10
Joined: Tue Mar 25, 2014 4:09 pm

Re: W108 Mercedes 280SE diesel conversion project

#94 Post by cdodgyd » Thu Dec 04, 2014 1:44 pm

A few veggie users here I see!
Today was frosty - still started straight away on 100% soya oil! Damn Bookers just put up 20L oil to 15 quid though.

Perhaps I should have mentioned my Sprite has an Atlantis type conversion ie. its running a Ford Crossflow with twin 40's!
Just worked it out - back in the summer with petrol at 1.30/L and no more than 25mpg (being generous!) it was costing me £23.60 per 100 miles. As a fun car it doesn't matter that much; its is not used in the winter and I wouldn't regard it as a "practical classic"! Even if it was standard doing 40mpg, that still means £14.77.

The Merc at 28mpg was costing me £13 per 100 miles. I was paying 80p/L then though - cooking oil has dropped just like pump fuel, so now its a little less in both cases.
(I do also occasionally get hold of waste oil and that's completely free but its a messy time consuming business getting it filtered.)

pryantcc
Posts: 289
Joined: Wed Jan 05, 2011 6:35 pm

Re: W108 Mercedes 280SE diesel conversion project

#95 Post by pryantcc » Tue Jan 06, 2015 9:23 pm

Some more progress being made, slowly but surely!
She's starting to look a bit rough :) I've most of the interior and doors stripped now and removed a lot of chrome trim, etc.
Image

Here you can see one of the 3 beautiful fibreglass patch-jobs I've found so far and what it was covering.
Image
Image


I found more rust in the rear floors under the sound deadening bitumen stuff, but nothing too scary.
Image

I chipped a bit of paint away from the base of the C pillar where it was bubbling. There are small perforations, but, to be honest I expected it to be worse. I was surprised, though at how far the rot goes under what seemed to be good paint from the outside!
Image

I bolted up the flywheel and clutch. I re-measured all the clearances with respect to the gearbox input shaft length, release bearing position, etc. It couldn't really have worked out any better, everything has fitted perfectly.
Image

The big news is that my welding expert friend visited earlier in the week and fixed my gear shifting mechanism in place. It worked out well in terms of position and seems like it'll be very comfortable to use. This feels like a big step as all the mojor requirements for driving are now in place. Happy days!
Image

pryantcc
Posts: 289
Joined: Wed Jan 05, 2011 6:35 pm

Re: W108 Mercedes 280SE diesel conversion project

#96 Post by pryantcc » Mon Feb 02, 2015 11:17 am

There's been a major push the last few weeks. I'm sorry to say I've very few photos. Plumbing has been a large part of the work, there was quite a list:
Feed for clutch master cylinder
Intercooler
Oil cooler
Radiator
Power steering
Oil pressure gauge
Temperature gauge

The clutch master cylinder was the easiest part, just a length of hose from the brake reservoir down to the master cylinder.

Image

The intercooler needed a custom pipe to be welded up to get down around the alternator and the anti-roll bar. the intercooler itself isn't permanently attached yet, but fits well between the two front bumper mounts.

Image

For the oil cooler, it was a bit more involved. In the original car, the oil cooler is actually boldted onto the right side of the radiator, in line with it, so, apart from being unboltable, it is effectively an extension on to the side of the rad. The biggest problem with this was that the oil cooler plumbing on the new engine was on the left hand side. In order to move the cooler to the other side, we had to de-solder the sides off the rad and swap them around. You cna see it in its new position on the left of the rad in this photo:

Image

Once this was done, it was clear that the top connection on the cooler was going to interfere with the power steering pump.

Image

The solution was to swap the outlet position with what used to be the drain plug as the cooler is now upside down. So, we cut the fitting off the W210 E300 oil cooler as there was more meat in those and welded it to the oil cooler from the W108.

The W210 oil cooler:
Image

And the swap job on the W108 cooler:

Image

Once this was all sorted out, the only requirement was to extend the oil feed lines slightly to reach the cooler.


The top connection on the rad is very close to the outlet from the engine, so a bit of bodgery was required to get them connected. I got a couple of tight bends and cut and joined them. It's a little rigid as the engine moves about under power, but I'll try to sort that out by spreading the two halves on the joiner.

Image


The power steering was probably the most awkward to sort out. In terms of plumbing, the guys making up the hydraulic pipes had nothing that would fit the pump end. So, my good welding friend cut the original pump connector and welded it to the hydraulic fitting.

Image

Image

Image

Image

Now, I also knew that the pump output would produce about double the pressure of the old original one, so presumed that hooking my more modern version up to the ancient steering box would result in bad things. So, I bought a gauge for £7.50 from Ebay, and, welding ecxpertise was required again to put together a fitting so that it could be connected to the end of the high pressure pipe.

Image

Image

An evening of testing followed. The pump registered just over 100 bar at the start and I was aiming for around 60. There is a pressure relief valve inside the pump body, a very simple arrangement with a spring that holds a ball bearing against a seat until the pressure pushes it off the seat against the spring. There were a few shims in it, so I went about adjusting with shims. The first try had only minimal impact +/- 2 bar, so adjustment was acheived by shortening the spring with careful application of the angle grinder! 3 or 4 tests later and the pump was outputting about 60 bar.


More welding was required to fit the engine oil presure gauge. There's a nylon pipe running to the back of the pressure gauge in the dash which feeds the pressure up to the mechanical gauge. The diesel engine had a handy bung at the base of the oil filter housing which was removed, drilled out and welded to the fitting from the petrol engine.

The temperature gauge is a vial on the end of a capilliary tube which runs to the back of the dash. The fitting from the petrol engine went straight into a handy hole which was plugged in the diesel without any modification.

If you're still reading, fair play! Here's what I'm getting around to:

[YOUTUBE]_nevB8yOQ0Y[/YOUTUBE]
http://youtu.be/_nevB8yOQ0Y

It works!! The first time in about a year she's moved out of the shed! The drive went well. Gearing is very low as was expected, but I'm very happy with the way the engine behaves. It's hard to tell what it'll be like until you have it on a manual gearbox, but it's great. Clutch and gearbox work nicely too. I'm very happy and really like it. I'll try significantly bigger wheels and tyres shortly. According to my calculations, +2 inches in diameter will have me cruising at 70 and 2,400RPM.

User avatar
TerryG
Posts: 6750
Joined: Wed Jan 05, 2011 1:54 pm
Location: East Midlands

Re: W108 Mercedes 280SE diesel conversion project

#97 Post by TerryG » Mon Feb 02, 2015 11:25 am

You have been busy! it is always such a boost when your project moves under it's own steam.

Unfortunately the forum doesn't support embedded videos so for those of you that want to see a clip of Paul's merc it is here:
https://www.youtube.com/watch?v=_nevB8yOQ0Y
Understeer: when you hit the wall with the front of the car.
Oversteer: when you hit the wall with the back of the car.
Horsepower: how fast you hit the wall.
Torque: how far you take the wall with you.

bnicho
Posts: 761
Joined: Wed Jan 05, 2011 8:35 am
Location: Melbourne, Australia

Re: W108 Mercedes 280SE diesel conversion project

#98 Post by bnicho » Mon Feb 02, 2015 11:23 pm

Flipping Brilliant! :D

Rather than bigger tyres you could change the diff centre. 2+ inches taller would make it look a bit odd and might restrict the steering.

Cheers,
Brett Nicholson
1965 Morris Mini Traveller - Trixie
1966 Austin Mini Super-Deluxe - Audrey
1969 Morris Mini Van - Desert Assault Van
1971 Morris Moke - Mopoke
1974 VW Super Beetle - Olive
2009 Nissan Pathfinder

pryantcc
Posts: 289
Joined: Wed Jan 05, 2011 6:35 pm

Re: W108 Mercedes 280SE diesel conversion project

#99 Post by pryantcc » Tue Feb 03, 2015 4:25 pm

Thanks Terry, it goes forwards too!

Brett, if you can find me a 2.82 ring & pinion from a 6.3L car, I'll use it :) I have looked into changing the ratios, I've currently got 3.46:1 which I think is the taller of the readily available ones.

I'm just going to put big wheels on to see what it's like. I can get them very cheap so will give it a go and see how it is.

alabbasi
Posts: 242
Joined: Wed Jan 12, 2011 9:54 pm

Re: W108 Mercedes 280SE diesel conversion project

#100 Post by alabbasi » Tue Feb 10, 2015 1:26 am

pryantcc wrote:Thanks Terry, it goes forwards too!

Brett, if you can find me a 2.82 ring & pinion from a 6.3L car, I'll use it :) I have looked into changing the ratios, I've currently got 3.46:1 which I think is the taller of the readily available ones.

I'm just going to put big wheels on to see what it's like. I can get them very cheap so will give it a go and see how it is.
I have one sitting on the floor from a 69 6.3. LSD with vented discs. But It's in Texas :)

Post Reply

Who is online

Users browsing this forum: Zelandeth and 1 guest