500/560 SEC Project advise.

[carat 3.6]

Is there much mods needed in terms of engine and gearbox mounts?

Engine and gearbox mounts need to be custom made for the m113, but is a fairly easy job in a w126. The m119 can use the original mounts in the sec.

Did you have a goal in mind for power output, or just interested in having a newer engine in the old car?

 

[WDB124066]

Thought that looked familiar...

 

[GT500E]

Engine and gearbox mounts need to be custom made for the m113, but is a fairly easy job in a w126. The m119 can use the original mounts in the sec. Did you have a goal in mind for power output, or just interested in having a newer engine in the old car?

The main goals are
More power
Wide body kit
Must be 30+ years to get classic tax(€56 per year). Otherwise over €2k per year here.
Big comfortable cruiser
Benefit from modern mod cons - heated seats, sunroof, etc etc
Improve reliability with the modern engine.
Autobox



In terms of power I am not looking to build a drag car...like the mustang I wanted enough power to have a little fun from time to time but in general I enjoyed cruising and the noise more. I would like to get it into the 500bhp club or above but I know at some stage it means spending big money on chassis, suspension, etc then I would go with an older v12. I suppose I am looking for a happy medium between power and overall cost. If 500 bhp is achievable for less than £10k I'd be happy. The idea of the of the M113 engine with m800 engine management unit is really appealing to me at this stage but I am still looking at all options.

 

[Niks]

I think you'd probably be looking at around £15k if you went the M113 route with the supercharger or a twin turbo setup up (Weistec isn't cheap but it's very good stuff!!). The M119 is a very good engine - don't get me wrong, but most of the mod work on that will be all custom work. Where as you'll find more on the shelf performance options available from Kleeman, Renntech, Weistec and so on for the M113, especially thing's like lightweight pulleys.

A fair portion of your money will go into the fine tuning side of things. The MOTEC 800 or actually even Megasquirt MS3X will give you a base setup to get the engine going, then it needs to be fully mapped to your spec on a dyno - you'll require a few runs. Beauty of this is you can always 'edit' your maps live as your driving with the software on your laptop connected to the ECU in realtime if you ever wanted to. For example, you could load a map for just general driving, another map for outright power if your going to drag it or race it.

M113 should go straight in as its smaller than the M119, the 722.6 gearbox already works with that engine anyway so your pretty much sorted there. I have a guy who can modify the 722.6 to handle around 800-1000bhp. Custom make a balanced driveshaft and modify the rear subframe to accommodate the Quaife LSD.

Then I think you'll be well on your way to 500+ bhp.

 

[bolide]

Why not find a decent SEC and drop an LS crate motor & gearbox into it? Assuming the manifolds clear the steering, the only complications should be propshaft, speedo, gear linkage and SLS pump

If you want to stick with an MB engine I'd recreate a period AMG car with all their mods. That will add value

Nick Froome

 

[John Jones Jr]

The main goals are
More power
Wide body kit
Must be 30+ years to get classic tax(€56 per year). Otherwise over €2k per year here.
Big comfortable cruiser
Benefit from modern mod cons - heated seats, sunroof, etc etc
Improve reliability with the modern engine.
Autobox



In terms of power I am not looking to build a drag car...like the mustang I wanted enough power to have a little fun from time to time but in general I enjoyed cruising and the noise more. I would like to get it into the 500bhp club or above but I know at some stage it means spending big money on chassis, suspension, etc then I would go with an older v12. I suppose I am looking for a happy medium between power and overall cost. If 500 bhp is achievable for less than £10k I'd be happy. The idea of the of the M113 engine with m800 engine management unit is really appealing to me at this stage but I am still looking at all options.

Is resale value or resale appeal a major factor? I do think it's worth pondering on especially if the base SEC is a very good one to start with. Very easy to buy a good/expensive car spend the same again or more and end up with devalued one. I'm not implying that's what will happen but it has happened to many in the past. No doubt you're aware but worth mentioning all the same.

 

[Red C220]

Question to those that have tinkered with this stuff.

The M119 and transmission from R129's are physically not a difficult fit in an SEC with some bulkhead modification to get the heads to fit, the major problem modifying RHD SECs is the position of the Steering box.

So, thinking laterally, how compatible is the R129 steering system with the SEC? i.e. would an engine, transmission and steering transplant be possible from an R129 in to a C126?

(I've owned and tinkered with a 560 sec but have never so much as lifted the bonnet of an SL).

 

[Niks]

There was a swedish guy transplanted a W210 steering rack into the W124, don't think that 124 ever saw the road again.

Personally I wouldn't have the guts to mess around with steering components.

Bolide - There's a SEC in the US with an LS3 in it married with a Tremec, its pretty awesome!

 

[carat 3.6]

The M119 and transmission from R129's are physically not a difficult fit in an SEC with some bulkhead modification to get the heads to fit, the major problem modifying RHD SECs is the position of the Steering box.

So, thinking laterally, how compatible is the R129 steering system with the SEC? i.e. would an engine, transmission and steering transplant be possible from an R129 in to a C126?

The steering box issue is nowhere near the huge problem people make it out to be, the m119 can be fitted in a rhd w126 or w124 and keep the steering box. Infact Ben's 190e with a 5.0 m119 fitted still has it's steering box, and of course there are there are the amg rhd cars which all kept a steering box.

The r129 and c126 both run a steering box, so there is no gain in fitting one to the other.

 

[carat 3.6]

There was a swedish guy transplanted a W210 steering rack into the W124, don't think that 124 ever saw the road again.

Personally I wouldn't have the guts to mess around with steering components.

Bolide - There's a SEC in the US with an LS3 in it married with a Tremec, its pretty awesome!

The w210 rack has been fitted in a number of w201's and w124's, it works perfectly if fitted correctly.

 

[carat 3.6]

In terms of power I am not looking to build a drag car...like the mustang I wanted enough power to have a little fun from time to time but in general I enjoyed cruising and the noise more. I would like to get it into the 500bhp club or above but I know at some stage it means spending big money on chassis, suspension, etc then I would go with an older v12. I suppose I am looking for a happy medium between power and overall cost. If 500 bhp is achievable for less than £10k I'd be happy. The idea of the of the M113 engine with m800 engine management unit is really appealing to me at this stage but I am still looking at all options.

The question is, would you want to drive a 500hp sec without doing something about the brakes and suspension? I would say your looking at 5k to make it handle and stop well enough to use that kind of power.

The m113 with all the parts you need to make 500hp fitted in a sec, is going to cost alot more than 10k. Infact Niks guess of 15k is cutting it fine.

If I was going to spend that sort of money, I think I'd fit an m275 v12 from a cl600 bi turbo for a standard 500+hp without mods. You can always fit larger turbo's and intercoolers if you want more power.

 

[Red C220]

Having owned a 560 sec the 300hp it made standard was quite a handful. It really isn't going to handle much north of 380hp to 400hp without major modification and I'm just not sure it's the right car for so much power. It really is a cruiser and not a sports car.

This thread has got me thinking though.

I'm still convinced the M119 is the way to go with this car, but as the 6.0 AMG motors are simply a fortune it would probably make more sense to modify a good 5.0 engine (increased capacity) to make 360-380hp.

Don't think forced induction suited these cars (IMO) despite some being supercharged over the years.

My ideal SEC is narrow body M119 6.0 - it's of the period, produces plenty of power but more importantly is in keeping with the car. A 6.0 32v DOHC naturally aspirated V8 is just right.

When I finally wear Jay down enough to part with his Blue SEC that's when I'll start tinkering for real.

 

[carat 3.6]

This thread has got me thinking though.

I'm still convinced the M119 is the way to go with this car, but as the 6.0 AMG motors are simply a fortune it would probably make more sense to modify a good 5.0 engine (increased capacity) to make 360-380hp.

M119.960, fit the 560's crank and rods (direct bolt in), increase the bore size to take your custom pistons. = 6.2 v8 with 420ish bhp.

 

[Red C220]

M119.960, fit the 560's crank and rods (direct bolt in), increase the bore size to take your custom pistons. = 6.2 v8 with 420ish bhp.

You make that sound very straightforward.

How much of a problem is the ECU and fueling for a modification of this nature? Or would you retain the existing M117 intake and fueling system with the M119 motor as was done in Japan?

This sounds genuinely dooable.

Also how do you overcome the steering box issue?

 

[carat 3.6]

You make that sound very straightforward.

How much of a problem is the ECU and fueling for a modification of this nature? Or would you retain the existing M117 intake and fueling system with the M119 motor as was done in Japan?

This sounds genuinely dooable.

Also how do you overcome the steering box issue?

It is very straightforward, that's why the jap's preferred to build those over the 32v m117. You can run it on the m117 management for period correctness, or use an aftermarket ecu to get the best out of it.

There is no steering box issue to overcome, you only need to alter the firewall to clear the heads. Then re-work the exhaust down pipes.

 

[Niks]

Why tinker round with a M119 or M117 to get more power when the M113 5.5 already has 350bhp out of the box? In today's age, I would ditch the 25yr old CIS-E/distributor cap/rotor arm crap and go full standalone - far more tuneable and gives you the perfect foundation of further tuning down the line. Plus, the OP mentioned something modern, not period correctness.

 

[carat 3.6]

Why tinker round with a M119 or M117 to get more power when the M113 5.5 already has 350bhp out of the box? In today's age, I would ditch the 25yr old CIS-E/distributor cap/rotor arm crap and go full standalone - far more tuneable and gives you the perfect foundation of further tuning down the line. Plus, the OP mentioned something modern, not period correctness.

let's do some comparisons...

Your going to need £2k+ worth of standalone ecu to get the m113 to run in the sec, your also going to need a transmission controller to run the gearbox, custom propshaft, custom throttle pedal. Then of course £1k+ for buying the m113 and box. So that's £4k gone to get the standard 350hp m113 running.

Whereas you can get a m119.960 for £500, which will work with the original gearbox and mounts, and can be made to run on the 560 management if desired for 325hp. That is a £3.5k saving!

Or throw a £1k standalone ecu on the later m119 to get 350ish hp, that's still 2.5k cheaper than the m113.

Your saying the cis-e and distributor controled ignition are crap, but the m119 didn't gain any hp when it changed to efi and coil on plug technology. So it obviously wasn't holding that engine back.

I can tell you that with the m119, 500hp can be done inside 10k. However I cant see the same happening with the m113.

As for the modern engine comment, the m113 has been around since 1999 so is hardly a modern engine.

 

[Red C220]

Is there any benefit keeping the existing W126 gearbox. I was of the understanding that the M119.960 plus transmission from a 90/91 SL500 would be a straight swap physically and that the gearbox would be an improvement over the W126 item?

 

[ianrandom]

The w210 rack has been fitted in a number of w201's and w124's, it works perfectly if fitted correctly.

I've heard of this in an SEC too, although the car in question is currently a work in progress.

 

[BTB 500]

Having owned a 560 sec the 300hp it made standard was quite a handful.

I know little about SECs but had no idea the 560 put out as much as 300 bhp in stock form?