W114 Performance

[armand4]

Hey everyone-- thanks in advance for advising this vintage Mercedes newbie!

I'm going to be getting a '70 250 with a leaky column-shifted automatic and an engine that runs but is, in the previous owner's words, "tired and old." I'll see if I can figure out what's wrong with the engine (I haven't taken delivery of the car yet) but the current tentative plan is to swap in another M130 motor, preferably one with a 4-speed.
As long as I'm going to have the motor out, though, is there anything I can do to make the car a little faster? Can the M130 be tweaked (milling the head to increase the compression ratio comes to mind) to produce a little more oomph? If I'm already getting a different motor, does an M110 offer better performance potential? I've heard it bolts up in the same places as the M130-- does that include the manual transmissions?

I'd appreciate any advice-- I've always liked these cars, but this will be the first one I've actually worked on.

[alabbasi]

Yes, the M110 is a generation ahead of the M130 and more powerful. Fixing your engine will also yield more power as a good M130 does not perform too badly.

[socalbenz]

There are not a lot of performance improvements to be made on these engines. Mercedes engineered them pretty well. On the M130 you can put in a European cam and gain some improvement, but those cams will set you back more than a few $$. The Mercedes bottom ends are pretty solid, do a compression test before you decide to abandon the block. A Valve job might be all that is needed. If you do decide to swap to a M110 do a thorough job of planning the project and price all the parts before you commit. Engine swaps are rarely straight forward. Your costs can balloon pretty rapidly if you are not careful.

[tram]

Start with checking the valve adjustment. Valve adjustments are too often ignored, and engines are way happier when the valve adjustment is correct. Valve adjustment can also directly impact compression.

I've seen valves so far out on "old tired" MB engines that they would crank but not fire when warm. Adjusting them can make the difference between "old tired" and "young strong".

[Skippy]

Valve adjustment and compression and/or leakdown test before you condemn your engine. When mine was running right it was decently quick, about even with my turbo 300D, and this is at 4700 feet elevation.

If you can get the parts together to do a four speed swap it would be good. The automatics are ok when they work right, but getting them tuned right is becoming a lost art. About six months ago I talked to a member in California who had the appropriate four speed and parts. Vegestar. I don't know if he still has that stuff for sale, but it's worth a try.

BTW, my 114 is for sale. The short block is good but it will probably need a cylinder head. PM for details.

[armand4]

I'm definitely going to look very carefully at the current engine before throwing it away-- I'd love for the "tiredness" of the engine to just be a symptom of a few poor adjustments. I still want to do a four-speed swap, though. When I was 16, I considered buying a '69 250 with four on the floor, but a little bit of rust in the floor scared me away... of course, since I was young and stupid then, I probably would have ruined the car anyway!

While I'm bench racing-- that is, before the cold reality of buying parts to freshen up a car hits me-- does anyone here have any experience at sharpening up the W114's handling? New shocks and rubber bits would probably be at the top of the list for firming up the handling, but has anyone gone farther than that?

[tram]

Originally Posted by armand4

I'm definitely going to look very carefully at the current engine before throwing it away-- I'd love for the "tiredness" of the engine to just be a symptom of a few poor adjustments. I still want to do a four-speed swap, though. When I was 16, I considered buying a '69 250 with four on the floor, but a little bit of rust in the floor scared me away... of course, since I was young and stupid then, I probably would have ruined the car anyway!

While I'm bench racing-- that is, before the cold reality of buying parts to freshen up a car hits me-- does anyone here have any experience at sharpening up the W114's handling? New shocks and rubber bits would probably be at the top of the list for firming up the handling, but has anyone gone farther than that?

Look for broken stabilizer links front and rear. Rears are notorious for just coming apart as they age.

The second biggest enemy of handling on these cars (aside from loose/ worn components, any of which you find should be replaced) are tire shops, the vast majority of who automatically pump the pressure up to the max on the sidewall.

The CORRECT way is using your OEM inflation specs for front and rear (in owner's manual or in gas flap) and add 2 PSI for P-Metric (post 1980) radial tires. Don't worry about what size your tires are- they're probably not the exact original anyways- as pounds per square inch is a constant value.

My philosophy is to always do the simple stuff first. You could rebuild or replace every component in the steering and suspension, but, for example, if the tire pressure is 40 PSI all around, it'll ride like a skateboard.

[JimFreeh]

Originally Posted by armand4

While I'm bench racing-- that is, before the cold reality of buying parts to freshen up a car hits me-- does anyone here have any experience at sharpening up the W114's handling?

A W114 with nice tires and a tight standard suspension handles sublimely.
It's going to be difficult, if not impossible, to improve the handling of the car without significantly compromising the ride quality.

Shocks, rubber bushings, steering shock, tie rods, steering box, etc., all need to be in first class order before making any changes. Get it right, and you'll be amazed at what the car will do with the stock suspension.

Jim