Mercedes W114 250 Coupe - help!

[Charles Morgan]

Returning to the V8, we have established that (ignoring engine bay rigidity) an M116 V8 could be made to fit, but the rear diff from a W126 donor would be too large. Reading the numerous threads elsewhere the W116 V8 diff is the same size as the W114/5, as indeed would an 85 W126.

(Remind me Druk which diff you ended up with in the 107?)

If that is the case then fitting the auto box and making the engine work in a standalone situation are the key factors, with everything else a bit of a bore but doable.

If not, then a small block chevy returns to the frame.

 

[grober]

Nice section of the Wheeler Dealer programme on the TR6 on the work involved on replacing hardened valve seats [ exhaust only] for unleaded fuel from 21 minutes onwards.
+[YOUTUBE]mn2kUJAUbFM[/YOUTUBE]

 

[Druk]

(Remind me Druk which diff you ended up with in the 107?)
.

2.47:1 from a pre-facelift W126 380SE. Had to convert the axleshafts to the W124 pattern flanged output but other than that it fits the 114 rear subframe directly. The input flange has a greater PCD but that's a minor problem.

 

[Charles Morgan]

While you're on the line as it were, was there a reason you went manual rather than auto?

 

[Charles Morgan]

2.47:1 from a pre-facelift W126 380SE. Had to convert the axleshafts to the W124 pattern flanged output but other than that it fits the 114 rear subframe directly. The input flange has a greater PCD but that's a minor problem.

Would the axleshafts need doing on a car of my era?

 

[Druk]

While you're on the line as it were, was there a reason you went manual rather than auto?

722.6 gearbox on the (ex)W210 that came with the engine was mega-tight fit in the tunnel and also has stand-alone control problems. Although both these excuses can now be overcome with hindsight/fresh knowledge. 722.3 gearbox which would fit won't handle turbo power...allegedly.
Getrag box easily handles power and is good fun but has 1:1 5th gear hence 2.47:1 diff.

Would the axleshafts need doing on a car of my era?

Not sure. The axle seal retainers on the 126 large-case diff are quite large and protrude out past the side of the diff case much further than on the small case diff where they are almost flush. This might foul your inner CV joints or the splined part may not extend far enough into the diff to engage the gears. My main reason however was because I had done a flanged axleshaft conversion a couple of years previous and there was no way I was sacrificing £1600 of nearly new kit. I'm typing away from home on an iPad and can't access my photobucket account to illustrate...sorry.





.

 

[Charles Morgan]

Well, if the 722.3 box came from James 420 it should be capable of handling the torque.

There's a 450 SE diff on ebay at present - it's final drive could be 2.65-3.07.

I've also found a guide to changing diffs on the W114 - how cool is the internet?

 

[Druk]

 

[grober]

If you go down the Carb ROUTE these guys might be worth a look?
Weber Conversion Kits - German Cars - Mercedes - JAM Engineering Fuel Systems

WITH REFERENCE TO THE ABOVE HERE ARE THREAD DETAILS OF THEIR SOLEX CONVERSION KIT INSTALL
Mercedes-Benz Ponton Type 220S Weber Carburetor Conversion ? www.mbzponton.org

 

[swampmonkey]

Well, if the 722.3 box came from James 420 it should be capable of handling the torque.

There's a 450 SE diff on ebay at present - it's final drive could be 2.65-3.07.

I've also found a guide to changing diffs on the W114 - how cool is the internet?

a 450SE has the 3.07 or 3.06, the 450se 6.9 has the 2.65 witch also is LSD (like always)

and yes, im the writer of that guide, internet rocks
the change isnt impossible but a few tips-and tricks make it a lot easier, especially the first times, you need patience for the manouvre

lifting the diff up is the thoughest part.


regarding engine, why not a om602 or om605 turbo paired to a fivespeed, compared to the m104, m103 and om606 they are easy to fit in there, and you get a tad better fueleconomy.

either way, a new differential is neccesary, the v8 differentials have a larger flange/yoke, but besides that fit directly. the 240d on mbturbo.com had the flange changed on that 2.65 diff, as the 2.47LSD on the mynä w123 had to.

but! if you are going for a new engine, and has to redo the cardanshaft/driveshaft whatever you call it, keep the larger flange, and get a shaft from a v8, bigger hardydisc is always better, + to change the flange is a bit of a job. (total dissembly of the differential if it is to be done correctly)

i run a 3.07 on a 72hp 240d w115, a 2.88 on another 240d, and a 2.65 on the 300d turboconverted w115,

should be able to run a 3.07 and a fivespeed if you want good fueleconomy even on a NA om605.

(a turbo engine will be a tad harder to get in place clean and nice since its a lhd car, the stearingbox is in the way of a larger downpipe.

 

[Bellow]

Well, if the 722.3 box came from James 420 it should be capable of handling the torque.

Would that include the 420 motor (M116 'small block'?)? Do I detect a jump in a particular direction?

Forgive the thread jack please - but - your difficulty with M104 in the W124 caused by wheel speed sensors. Non switchable(off) traction control?
I'm still trying to nail once and for all whether an M104 (from a W124) with autobox (any autobox) can run as standalone (Druks comments appear to relate to the later W210).

- how cool is the internet?

Very!
But it does throw up odd questions after raking about in the past. In 1969 PAS was an option on a W114 (as was auto transmission). Does your W114 have PAS? While I was back in '69, I was surprised to find that the rear suspension is the low-pivot swing arm set up (as in the Pagoda) not the semi-swing I thought. Is that correct?

 

[Charles Morgan]

Swampmonkey - thank you very much indeed, first for your internet guide - I can't tell you how helpful finding these routes are.

Second - for helping here. If I bought a V8 with transmission from a later W126, would the flange from that car work with the W116 diff?

I'd love to find a W116 6.9 diff with LSD! I suspect they are quite rare though!

 

[Charles Morgan]

Would that include the 420 motor (M116 'small block'?)? Do I detect a jump in a particular direction?

Forgive the thread jack please - but - your difficulty with M104 in the W124 caused by wheel speed sensors. Non switchable(off) traction control?
I'm still trying to nail once and for all whether an M104 (from a W124) with autobox (any autobox) can run as standalone (Druks comments appear to relate to the later W210).

The later W124s had ASD as an option and also the five speed auto with 5th operated electronically. IIRC correctly these operated with input from the ABS sensors - unless I'm mistaken the earlier W126s with the four speeds had none of these extras. I have asked a chap who does know about the 104s and the ECUs to get a final answer to your question.

 

[Charles Morgan]

But it does throw up odd questions after raking about in the past. In 1969 PAS was an option on a W114 (as was auto transmission). Does your W114 have PAS? While I was back in '69, I was surprised to find that the rear suspension is the low-pivot swing arm set up (as in the Pagoda) not the semi-swing I thought. Is that correct?

I don't know about PAS on mine - I need to have a good look.

All I have read has said the W114 has a different suspension set up to earlier Mercedes and it had semi trailing arm axles, not the swing arms of the early 60s cars.

 

[Bellow]

I'd check it has PAS before installing a heavier engine!

I thought it had the semi trailing system that was then carried through to the W123 but reading the test of the 280 from 1969 Car appear adamant it has the low-pivot swing arm set-up. Perhaps an LJKS blunder!

 

[Charles Morgan]

Far be it from me to question LJKS rabbinical infallibility but for their 123 test they get it right. As the W114 has the same rear suspension as the 123 I think it was a boob.

No PAS makes fitting the V8 easier!

 

[grober]

I am still plugging the possible Weber twin progressive choke option with two 32/36 DGAV Carbs. Its imperative these are jetted correctly for their particular installation of course which means sourcing them from someone who knows the characteristics of the engine you are installing them on. Here's a video of a guy installing the electric choke version on a MAZDA pickup- its a bit haphazard but does give a nice VISUAL guided tour of the carb. Posted really for any "fuel injection generation" folks following this thread unfamiliar with this rather ancient technology?
[YOUTUBE HD]jFS5gPVK5Hk[/YOUTUBE HD]

 

[Bellow]

Semi swing.
http://mb.bolinko.org/wis/w114/Chassis/35-420.pdf

No PAS?!! Aircon?!!! One or the other or we'll lose you some summer!

 

[Charles Morgan]

A quick google reveals the alloy M116 to be the same or slightly lower weight than the M130 (the larger version of the M114).

Meanwhile, the car's white with a sunroof, so I might just survive the summer!

 

[grober]

Mercedes used to refer to it also as "diagonal swing axle" rather than semi trailing arm which I think is essentially the same thing. hence perhaps the mix up?