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1989 W201.029/M103 3.0
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Discussion Starter #1
Hi, I'm relatively new to the forum but really getting into the 70's-80's Mercs for value for money and engineering I truly respect. The W123 and W126 especially has really won me over in the affordable second hand vehicle range. They look fantastic for their age, seem to wear phenominally well and seem projected to take to modification like a duck to water. I for one love that because I just can't leave a car alone until it spins the wheels at 50mph but still looks like basically the original engine beneath all the polish and braid. It's something which just impresses the hell out of me.

Normally I'll compromise for big cam overlaps that snort and rock the pavement and more carbies than you could almost stuff under the bonnet, rather than go the whizzing hi tech route of turbo's and twin cams. What can I say, I like grunt and fumes...so that people say, "Oh no way, I thought that was a big block chev 'till you opened the hood."

And I've got some great engineering software plus a little experience under my belt (note: I do mean little as opposed to a lot, but I'm pretty confident about much of it).

I've driven cars that looked like I borrowed it from granny, 'till you heard the rumble, checked the exhaust diameter and noticed the offset on those "stock" rims hid 10 inches of rubber under the back.
CBR 1000's and the like would test themselves to 100mph against me. Turbo'd rotaries never stood a chance and only professional street/strip builds at the track really took me (and not until half marker). Not bad for a smartly built, $5000 budget I must say.

My current project is the fantastic looking W123 coupe and stage one, whilst I'm putting away the savings and biding my time for a good, 280CE example is getting to know these engines inside and out. That's how I got so much out of the last one (mates were giving me racer's publications on getting 3hp per cylinder here, 2hp there, it paid off when I finally put the thing together...I seemed to know more about that motor than the engine builders I had contracted, in fact I had to retune it in the driveway when I picked it up because they didn't know how to do the carby setup, so it was especially handy, just to get the damn thing going).

I've been computer modelling various setups on the M110 2.8E engine, from mild to wild and have just started on turbos. Got 220-300bhp naturally aspirated projections but topped 350bhp straight off the bat with a basic Garret turbo spec and decent boost. And that's much more like it (and not real expensive too). Of course one might want to retard the living bejesus out of the spark between about 3500-4000rpm but that's 12-14psi for you, I managed to get the knock index back down again.

So has anybody turbo'd the 2.8 around here? I'd like to hear about your engine, whilst I keep running these models and saving money for the project. Probably handy to hear about manual transmissions for the W123's too. Diff centre options. All sorts of tech stuff on this model...everything anybody can tell me I suppose.
 

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84 300TD, 2004 E320 wagon, 2006 CLS55,
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The 280 CE is fuel injected- so I'd love to see what you did when " they didn't know how to do the carby setup " ...
If it was the non injected model you'd have a 280 C.
 

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1989 W201.029/M103 3.0
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244 Posts
Discussion Starter #3
By "last one" I meant my last (modified) car. It was a 3.3 litre OHV 1971 Torana, running about 310 degrees camshaft duration, 11.5:1 compression and a triple 1.75" SU vacuum carburettor setup (similar to a K-Jetronic being vacuum operated and without mixing bowls...jets just opened straight into the air stream at the throttle bodies, metered by needles on a vacuum cylinder).

So there were three mixture screws, three idlers, and a linkage connecting three 1.75" throttle bodies. Took a bit of intuition to set them up properly without a bank of diagnostic tools.
The engine builders just slapped them on and turned up the idle on the centre carby 'till it ran.

So after I zero'd the linkages between them, centred the mixtures to match each other and reset the idlers on all three identically, it finally ran properly, without over-revving the centre two cylinders alone and being all over the place from the front pair to the back pair.


I'm guessing the Bosch is a little easier to work with.
 

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1989 W201.029/M103 3.0
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Discussion Starter #4
My Engine Analyzer models have only been half sorted but I've gotten [email protected] projected so far with a blueprinted bottom end, a bit of headwork, custom cam grinds, exhaust system and a nice moderate single turbo with a 14psi boost. The stock early jetronic manifold is retained with upgraded throttle body and injector sizing.

I was going to do staged turbos but this seems much easier, less fuss and expense and all that.
I'm going to try playing around with centrifugal supercharging for more bottom end response and a bigger top end charge, I think the cost-return is going to be about the same between them and turbo's do perform better on the track.

I'll keep the thread posted as I sort the details and provide some cam grind details and such in case anybody's interested, I'll keep an eye on cylinder pressures and crank compression to keep the whole package bulletproof. A 380bhp M110 for a few thousand dollars plus engine is a nice thought.

I'm still considering a 5.0 M117 conversion but I like keeping original engines. Definitely want a manual.
W123 manual gearboxes, anybody know anything about them?
 

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1989 W201.029/M103 3.0
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244 Posts
Discussion Starter #6
Oh that's the dream photo. It's not mine, but what I've got in mind. I put it there to keep me focused on savings...I have to keep telling myself the smart thing to do is to save all the money you need for the whole project first and don't go splashing it all away trying to do it piece by piece. It just never ends up happening that way and somehow seems to cost twice as much not even getting there.

So it means I wait a little longer with no car in the driveway. Hence the focus photo. I can't stand having no wheels and I'm climbing walls here.
 

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1989 W201.029/M103 3.0
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Discussion Starter #7
Well on the stock 2.8E computer model I've put on a set of custom turbo headers and a free flow system, plus bolted in a Garret T-45 turbo with a 15psi wastegate adjustment and big intercooler, plus water injection. Bosch injectors are out of a M117 560.

Pistons are the low compression flat tops of the US/Aust. models which run at 8:1 and are good for turbocharging. I recurved the spark advance to lower the knock index at 4000rpm.

Projections are 350bhp SAE at the flywheel for this basically stock setup. Sounds good and super cheap to me.

So that's the goal. >$9000 locally for the CE model and about $3000 for the mods. Add another $1500 for wheels, tyres and suspension work. Give or take a little between any of the pricing.
Resale value should hover around the $11,000 mark and improve with my detailing quality and general maintainence schedule.

The manual gearbox will be an added expense I won't see anything back from, but I want one. Could work out cheaper to transplant a 2.8E into a smaller six/manual and change the badges. All the 280's I've seen are autos.
Been thinking about the earlier model too, can pick up nice 250CE's in those for $3000 around here and a few are manual.
 

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vanir - 3/15/2005 9:58 PM
I'm still considering a 5.0 M117 conversion but I like keeping original engines. Definitely want a manual.
W123 manual gearboxes, anybody know anything about them?
Hi
Vanir , I am thinking about v8 conversion in my coupe, but only m116 3.8 liter. What do you think about this engine?

I saw w123 coupe with 5 manual gear box and 2.3 liter engine.

Thanks
-Andrey
 

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W123 280E
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vanir - 3/16/2005 4:58 AM

W123 manual gearboxes, anybody know anything about them?
I dont personally know anything about them, but a Getrag from W124 is a gearbox that you cannot break with 280E even if you try. There's couple 300D turbo W124's in Finland with manual tranny. They're only burning those BMW clutches (from M5 i think?), nobody's been breaking transmissions. Or maybe they just dont tell if they are. [:D]

I don't know what it would take to attach a W124 manual box to W123. Swapping automatic transmissions is possible by changing the interior from 722.3 (w124) to 722.1 (w123).

What kind of torques are you getting from your modelings? Stock clutch can handle about 50% more torque than stock engine can produce.
 

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1989 W201.029/M103 3.0
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244 Posts
Discussion Starter #10
Torque projections are 385ft.lbs. with the Garret T-45 on a 15psi wastegate. But I'm not real brutal on manual gearboxes and diffs, they were inherent weak points on my last seriously modified 6 (LC Torana) so I got used to treating them with care (after going through two clutches and three diffs in less than 12 months, the gearbox had been a new rebuild with V8 splineshafts so it lasted).

Still, I'd love to afford a Getrag, oh definitely, but I think it's more likely my roof budget will have me with the W123 stocker I've seen mated to 2.5E's, a 4-speed I think it is. I'll just pop a decent clutch in it and make sure the driveline is properly balanced.
Didn't know the W124 had a Getrag though, I'll definitely check out how much my local Merc-specialist wreckers will do me one for. Maybe I can work out some kind of package for a 2.8E/Getrag, because it's looking like the budget will best go with a W114 250CE. And I kinda like 'em, they're funky and classic at the same time. Love to see one of those outrace a Supra without all the "show off" valves and 6" thick tailpipes, for a third the cost and twice the luxury.

____________________________________________

I'm not very schooled in the M116's as yet, I've still got to go to my brother in law's to pick up some discs with all their tech specs, so I can put them into the computer models.
I know the M117 impresses the hell out of me, I've sorta got a preference for the 5.0 litre in that but all my models are of the 560.
The M116, they're in 3.5, 3.8 and 4.2 litre aren't they? The best thing straight up about the smaller capacities in M116/117's is you can borrow the larger Bosch injectors from the bigger engines during re-engineering, which saves the expense of aftermarket EFI (which is what's putting me off the 5.6, that and the overall fuel consumption).

Anyways, all the Merc 8's look a pretty good layout to me. DOHC heads and aluminium construction is a real bonus. I understand early variants were cast iron so I'd say avoid those in a retrofit transplant. Even at 3.8 litre (around 232 cid), the fast burning aluminium and direct valve action should keep performance more than respectable, especially with the opportunity of including tubular headers with a necessary custom exhaust fitment, and perhaps a little headwork and mild camshaft grinds, since the thing will want to rev anyway..
 
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