I say buy a 6.3 to use on weekends, and buy a 6.9 for the regular grind.

You gotta be crazy to own these cars anyways, but it's sooooo much fun!

I just returned from a weekend trip to Chicago in my 6.9 and the drive was equally as good as the time we spent in the city

You know what? I would rather make a long trip in my M-100 (even back when I had the 1969 6.3) than in my '95 S420. I trust a "real" Mercedes more.

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Regards,
Aaron

Hi Dan and Gerry,

There is nothing wrong with my engine. To me it runs great. My dilemma, if you can call it one is, I dont have a brand new 300SEL 6.3 for comparisons sake. Just to be clear, the 6.3 I bought was driven on a regular basis and maintained on a regular basis. It was not sitting under a tarp or in a garage collecting dust.

To me the tranny shifts perfectly. The engine has no running problems. The only thing I did notice was that after I drove it for about 40 minutes or so, when I stopped for lunch and restarted it, it didn't fire up as easily as it did when I first started it earlier that day ie it took about 6 turnovers instead of 2 or 3 before it fired up - wondering if it had to do with the very wet rainy weather. Other than that the car runs well, starting from a stop light in 2nd or really first gear, the car easily squaks from first to second upshifts.

Now realizing that the car is 35 years old, I was curious about an engine rebuild because of the age fact. What would be prudent to change or rebuild the car if anything? How can I know what would need to be changed? I guess I really need to drive it more and I am sure I will find out, but the car had been driven on a regulr basis by the previous owner and had been maintained on a regular basis at MB by the previous owner - I have the receipts and I've spoken to the maintenance manager at MB and the mechanic who works/worked on the car in the past.

The only other thing I've found out (actually I heard it too when I first drove in it BEFORE I bought the car) is at a tight right hand, or left hand turn I can hear what sounds like the rear differential. To me it sounds like its the limited slip (my GT3 has a very active limited slip, so I am used to this same noise, but I'm not sure if it applies to this car as well, wondering if someone could shed some advice.

The only other thing is at slow parking speeds, especially when backing up there is a bouncy jerking motion that is felt in the car, kind of like a hopping.

The car has absolutely no rust. I have gotten 2 estimates from 2 different shops to repaint the exterior and redo the interior. The car is dark blue with parchement interior, so I think I will stick with this same colour. I have thought about going to black, but with the dash being a dark blue colour it doesnt make sense. The brightwork is in immaculate shape, even the estimator was surprised about the brightwork.

The car was repainted in 1993, and it is still in great shape.

The interior is in great shape. ALL of the wood is intact and clean no cracks or fading in it - even the one on the dash. The seat leather does have some cracking so I will change that. All of the windows work except for the passenger rear. The vacuum door locks work perfectly. The sunroof doesnt work.

The front brakes and bearings were done and repacked BEFORE I bought the car for the safety stamp.

One of the reasons I wanted to rebuild the engine was because since my car is a 1970 it has the lower 8:1 compression. I understand the rebuilds have 9:1. Stupid reason maybe, especially if the car runs fine on its own. I'm just looking at all the options. The mechanics at MB tell me the engine doesnt need to be rebuilt.

The car holds it levels properly for days. Only after a few weeks of sitting the front sags a little, one of the valves is slightly leaky on the front. All 4 airbags were replaced in 1992.

So far that's it. I think I am starting out with easily a nine as far as body shape goes. The one thing I do want to swithc out are the motor mounts and tranny mounts. But really what I need to do is spend more time with the car, and discover what else needs to be done.

The quote I have gotten for engine rebuilds are somewhere around 20$K.

I have gotten quotes for repaint including replacing all brightwork, except bumpers, replacement of all window/sunroof seals and felts, all door/trunk seals, rear and front window seals, and replacement of all door step plates for $9000K. Labour is at least half of this amount.
Is this too much?

A good quality repaint on a 6.3 is around $10K, so it sounds like your estimate is OK. Have them (or yourself) remove the chrome -- don't get it painted if they are just going to mask it. That includes bumpers emblems, and all other brightwork.

You need to get those brake hold bearings taken care of, ASAP. Try shooting some grease in there via the nipples; this is only a short-term fix, and in reality things need to be disassembled and fixed.

The non-willingness to fire up once run, is normal. It will get exacerbated on hot days, to the point where you will suffer the dreaded "vapor lock". Dan is very familiar with vapor lock - my car never did this luckily. There is a factory fix, but it is not 100% effective.

A hot, not well known tip to avoid this on a hot day or a "second start" situation, such as after running into a store for a short time: turn the key to the first position (not cranking the starter) until you can hear the whine of the fuel pump. Stay in that position for 15-30 seconds and then turn the key to start the engine. It should catch much faster. This circulates cool fuel to the engine from the tank and removes the warm/vaporized stuff from the lines.

Another tip for a common problem: if your tachometer suddenly goes "dead" on startup or while driving the car, just reach in and rotate the chrome bezel slightly to re-engage electrical contact and it should jump to life.

Cheers,
Gerry

Hey Gerry,

thanks for your reply. Yes the Auto Body Shop did say that they have to remove all the chrome - he won't mask it.

As for the brake holds, the grease nipples are right at the differential part on either side of the axles correct? I'm going to ask the MB service advisor to have those lubricated and see what happens.
If they need to be placed, is it a difficult job, and should I replace them with MB originals or is there a better alternative?

RR3,
I haven't had time to read all the posts, but the thread caught my eye, because I have had a new in the box set of factory pistons for an M-100 setting on my shelf for some time now.. If you or someone is interested, we could bargain a fair price.

Peter

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Auto Zentral Ltd.

Peter,

You can sell them to Robert Fenton over in San Rafael (415) 456-4077, or to Neil Dubey at Star Motors (www.300sel.com for contact info).

RR3,

You can just replace the brake hold support bearings with new factory units. They are made out of plastic but work just fine. Just keep them lubed once a year or two if you drive the car often.

Cheers,
Gerry

Autozen,

Are they forged or cast?
Original MB Mahle?

Gerry,

what do you make of the limited slip? noise in tight turns, I've noticed.

It's a question for Dan Smith, not me. I don't believe that my car had (has) limited slip. (I just sold my car last week). No experience with it, nor any sort of noise from the rear end.

Cheers,
Gerry

RR3,
I don't know forged from cast. I'm just a dumb old factory trained MB mechanic who never got into racing. I just service and repair MBs. This is a complete set of Mahle 6.3 pistons size 103.5 mm. Part # is 100 030 53 17. They are packed 2 to a carton and 4 cartons. These are original replacement pistons and not some cheap knockoffs. I've had them on the shelf for years. I even have a new set of cams somewhere.


Peter

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Auto Zentral Ltd.

the part number is slightly diff from ones that ive been quoted.
the ones I have seen quoted are 100-030-64-17 104mm, what is the difference?

Are you sure that isn't 54-17? The 104 mm would be the next repair size. You choose piston size depending on what size the bores clean up at. I looked all these bits of info in my TDMs years ago. I can dig it out again.

Peter

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Auto Zentral Ltd.

Three questions from three Benz fans;
Gerry, your blue 6.3 that you just sold WAS equiped with a limited slip diff. Thank God.
RR3, your talking about the next rebuild pistons, but they can be used on the first rebuild also.
Autozen, your part number and that 103.5 size is the first rebuil pistons.

Note to all, very few 6.3s have ever been rebuilt or needed it due to shot pistons. Maybe lack of regular oil changes yes but the motors are very tough. I suggest rebuilds only to stop the front and rear mainseal leaks. A 35 to 37 year old M100 will have leaks. I have never seen one that was perfectly leak free.
The very worst thing that can happen to any M100 is to leave it parked for over 60 days. The seal dry out on every sytem. 6.3s have a bunch of systems to rebuild. Not a pleasant thing on your wallet. Run one at least monthly, it's good for them.

never knew the vintages had a 6.3 engine, isn't that similar to the size of a CL63 or S63?

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[FONT=Book Antiqua]ProMeds[/FONT]

My BENZ 4 SALE

Yes indeed, the first 6.3 Benz motor appeared in 1963. No computer controlled anything. All mechanical. My type of auto. It's intended use, power for the Grand 600. In or around 1967 / 1968, a genious type, Erich Waxenberger, a Benz engineer, a Swabian no less, squeezed that 6.3 into a 109 body. It quickly acquired the moniker, The 6.3, by auto writers and fans. 1972 was the last year of production but one was actualy sold in 1973. All told, about 6500 were made and close to 2650 came to the USA.
Gerry was asked about forged or cast. All factory pistons, (I BELIEVE ANYWAY) were forged. The pistons I use in modifieds are cast. Forged are the tougher of the two. Oh well, can't have everything.
As usual, I'm going off subject now. GERRY, I used the new secret weapon today. First successful attept on dry pavement. Did it from a rolling start. Trigger point is 2500 RPMs, what a jolt. Never have I watched the speedo move in this fashion.

Dan: Assume you're talking about nitrous? That doesn't melt that big 6.3?

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Current:
2021 Charger Scat Pack Widebody "Sinabee"
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