Lack of power and acceleration

I love the body style of my 1962 MBZ 220 SEb convertible but am frustrated with its performance. Since it is in pristine condition with only 86,000 miles, I don't want to trade it for a 280 model with a better performing V8. You can never know what you are getting in a car that has over 30 years of history behind it. With my rust free favorite, I know what I have. On level surface its acceleration is just ok, but on a grade I have shift down and move over to the slow lane. On the grade that I normally travel that means a max speed of 45 mph at a noisy 5000 rpm and hope I am not blocking the trucks behind me. The question is: Is there anything that I can do to increase the performance in the area of add on or modification? Will a conversion, if one can be found, to the V8 with its transmission from the 280 model be a reasonable task? Do you have knowledge of anyone making an Chevy or Ford engine/transmission conversion in a 111 chassis? Since I am a long time second owner and don't know how the car performed when new, I am curious as to whether my transmission is functioning properly. Whenever I come to a stop, it doesn't drop down in to low gear and I end up trying to accelerate in second unless I stomp on the accelerator to get it in first. Also, if I climb the small grade to my home, the transmission will not downshift on its own and will slow to a crawl unless I stomp on the accelerator to down shift. Just smoothly floorboarding it doesn't do the job. Lastly, on the first drive of the day my power brakes do not operate. I appear to be in the manual mode until the engine warms up. After several minutes my power brakes take effect and operate normally for the rest of the trip. The only other symptom is that the brakes sometimes come on very harshly even with a smooth application. Any advice you can provide would be sincerely appreciated. Thanks, Gregg

[bstreep]

Greg,

Just to make sure I've got things right, this IS a fuel injected engine, right? If so, that engine should be developing about 115HP DIN (a bit more, maybe 130-135 SAE). According to the specs on Ray Ilich's page, http://members.aol.com/valueadded/ponton.htm, you should be getting a 0-100KPH of about 15 seconds. This is not much different than my 190SL. On a steep hill, it WILL slow down below 55-60 without downshifting (manual, rather than your auto). Also, I'm assuming that you are using premium fuel.

As for the transmission, I'm not that familiar with the autos of that vintage. On my '66 250S (long gone), you had to either stomp on the gas or manually shift it into 2nd to get it to start in 1st...

Not sure on your brake system either. Is it using fluid? Do you have WHITE smoke in your exhaust? When is the last time your brake system was 1) rebuilt, and 2) flushed? Ray has a good article on rebuilding on his site, and your brake system should be flushed every year... I think you have a similar booster to mine. On mine you can test how it's working by reving the engine and applying the brakes. If the little screen in the front of the booster will suction on a small piece of paper, it is at least working. I also know that on mine, there's a small reservoir for mineral oil on the back. Not sure if yours has the same...

Bill Streep
'57 190SL
'92 300E

[Jim H]

Do you know how the intake manifold vacuum is doing? If you have a vacuum leak it could affect power and brakes.

BCingU, Jim

[cth350]

I concur with the vacuum question. That is the most common point between the two systems.

There is a range of basic checks for the transmission and ignition system and the brakes. If they've not been looked at recently, check them out, one by one.

-CTH

I was able to resolve the power brake vacuum loss. As previosly mentioned, when the car was first started up, there was a lack of power assisted braking. After a few minutes, the boost vacuum appeard to have been restored and the braking normal. The suggestion to check the hose from the engine to the boost tank was accurate. The long hose from the engine to the moisture capture was fine but the short fabric reinforced hose from the moisture capture to the tank was dried out and leaked vacuum. Replacing the hoses corrected the problem.

[cth350]

Brakes down, now for the ignition and transmission.

Where I am in NY state, all the inspection stations now have dynamometers. I have yet to drop by with a car on an otherwise quite day and ask for a HP test, but I'm sure they can do it.

I would suggest treating your baby to a proper ignition review with a scope and make sure that it is to spec.

BEFORE this, you should make sure your valve clearance is to spec AND that your timing chain shows PERFECT alignment to the bottom end. Nothing like 30 years to add some stretch to a chain.

All of the above will set you back about 50$, if it's just at the diagnostic level. Replacing the chain IS a DIY job, if you have to tools, otherwise, pay the bucks. It WILL make a difference if those marks are not in sync.

THEN you can turn your attention to the transmission. If you haven't done so, check the vintage archives back several months (like when this thread started), and reread the posts about checking the solinoids. With the vacuum leak repaired, you should be in better shape, but I presume it's not perfect.

Lets leave the transmission discussion until after the ignition and valve timing is to spec. We can't possibly have such a lovely car not living up to its means.

Worse case, you can always drop in a 250SE motor & tranny; that's what benz did in 1965. Just be sure to pickle the original motor so that you can return it's "authenticity" should the need arise.

-CTH

PS. Pictures wouldn't hurt. How many of us have seen a 111 cabriolet?

[ctaylor738]

Sounds like a great car. As usual CTH has it nailed, but here is my thought.

The older MB automatic transmissions are power-eaters, epecially if you only hav 2.2 liters to work with. Consider a swap to a manual? That would keep the car orginal and make it fun to drive.

I did this with a 280E and the difference was like day and night.

Chuck

[Robby Ackerman]

I would also do a compression test. It is as easy as changing spark plugs. A single bad valve will really slow you down on a grade.

Robby