kickdown vs. micro switch

[Cees Klumper]

Today I noticed that my micro switch (mostly found on the intake manifold but, on my car -1969 280 SL- located on the firewall, it activates a solenoid on the automatic transmission when you press the accelerator pedal, as far as I know) was not working properly. After fixing it, it works again (I can hear the solenoid down below engaging and disengaging) BUT ... now my kickdown does not work anymore! When I disconnect the micro switch, the kickdown works again (but the solenoid then does not activate). Could it be that the micro switch is not hooked up properly, or that the solenoid engaging changes the pressure (or something else vis-a-vis the transmission) to the point where the kickdown does not work anymore?

Even stranger, up to recently, I am sure that the micro switch was hooked up and working fine (as I could hear the solenoid engaging then as well) AND the kickdown worked. I'm at a loss!

One more thing: the micro switch has three terminals (1,2 and 3). I may have reconnected one of the leads to the wrong terminal, i.e. to number 3 rather than to number 2. Meaning it will work in reverse to what is intended? I just thought of this now. I will go check next chance I get to go to my garage, but if anyone cares to comment, please do!

1969 280 SL automatic

[Bearcat]

Cees why do you want to kick down an old girl. I find reving my 280SL upto 3500rpm in norm mode is enough for me. I have never floored, never used my kickdown mode. I have heard all the usual argueements but these cars are old and in my opinion should not be brought up to their original limits unless one wants to see them self destruct.Its only an opinion Clees but I want to see my concours 280SL last a long time as I also see it as an investment.

280SL 1970
SL320 1998
E300T/D Est 1998

[n/a]

I rev the heck out of my car on a regular basis, and it's far from factory new spec. If it blows up, it blows up. I would drive it even harder if my 4 speed wasn't so recalcitrant. I'm wondering how good these 4 speeds were when new. Were they slick shifting smoothies or floppy, sloppy, gear grinding dogs?

Rudy
Los Angeles
1971 280 SL

[Roadstir]

Cees,

Any chance you have a digital pic of this microswitch?  I'm not sure what it looks like.  Did you replace it or just clean/tinker with it to get it running again?  Are they expensive to replace?

Thanks,

D

David

[ja17]

Hello Cees,
Sounds like you may have something hooked up wrong. The solenoid is trying to go both directions at once so it does not move at all.

Ruddy,
It sounds like you have a stick shift. If the spanner nut in the transmission output flange becomes loose, the transmission gear cluster loosens up. The result is gear nipping or grinding and difficulty shifting. A sure sign of this is that the speedometer needle will bounce when letting off the gas pedal. The speedometer drive gear in the transmission is also held tight by this spanner nut. also make sure all your shifter bushings and linkage are 100%.

Bearcat,
Naturally if you have a tired or weak engine you may want to pamper your 113. Some of the best running and longest lasting W113 cars I know of, are the ones that are run hard and exercised on a regular basis.



Joe Alexander
Blacklick, Ohio

[Cees Klumper]

Thanks all. I will take a photo of the microswitch next chance I get and post it here. The switch works fine now. I will try to hook it up differently (i.e. to terminal 2 rather than 3) and see if that helps.
I use the kickdown when I want to move from a standstill fast, e.g. up an incline at a traffic light. I converted to a 3.69 rear end (from 4.08) and, starting in second gear, the car is very sluggish. Pressing the accelerator briskly results in a 1st gear start.
But, having said that, I do use the kickdown also on regular driving, for passing for example. And I agree with Rudy, that the car should be able to be driven in the manner for which it was originally designed. If it cannot, one could say you don't have an original car.
Joe Alexander was so kind to teach me how to rebuild these engines last May/June, around the tech session (see full reports in that particular topic) so, if worse comes to worse, I can always lift the engine out and fix it! BTW the engine that Joe and I rebuilt is now on a ship, making its way over to the old country again. When it gets here, I will pick that thread back up and report how the installation etc is going.

[Bearcat]

Bearcat,
Naturally if you have a tired or weak engine you may want to pamper your 113. Some of the best running and longest lasting W113 cars I know of, are the ones that are run hard and exercised on a regular basis.



Joe Alexander
Blacklick, Ohio
[/quote]

[Bearcat]

quote:Originally posted by Bearcat



Bearcat,
Naturally if you have a tired or weak engine you may want to pamper your 113. Some of the best running and longest lasting W113 cars I know of, are the ones that are run hard and exercised on a regular basis.



Joe Alexander
Blacklick, Ohio

[/quote]

Joe, to the contary my engine is as tight as a nut. No smoke no nothing except all go and sings a beautiful rasp. I just wont floor her to 6000rpm....period. To me she's an old girl. I fly aircraft too professionally and as as a hobby and we baby the older aircraft hence my angle with the merc. I knew this would raise the heckles of some people. Bearcat

[Bearcat]

Originally posted by Bearcat

[Albert-230SL]

quote:Originally posted by Bearcat

Cees why do you want to kick down an old girl. I find reving my 280SL upto 3500rpm in norm mode is enough for me. I have never floored, never used my kickdown mode. I have heard all the usual argueements but these cars are old and in my opinion should not be brought up to their original limits unless one wants to see them self destruct...

280SL 1970
SL320 1998
E300T/D Est 1998

Hi Bearcat,

Just my 2 cents, and considering that everybody is free to drive his car at his manner    :

Maybe I'm too cautious with my Pagoda, but I agree with you about to drive more carefully these 30-40 years old cars than a new one (I guess you drive your R129 in a different way, as I do with my daily A-190). I wouldn't drive my 230 SL the entire time at 6000 rpm during a long trip on the highway*... Anyway, I think it's not bad at all if sometimes you use more range of revs (assuming that the engine is in good shape, and all -injection, ignition, etc.- is properly tuned).

The sound of the Pagoda engine/exhaust seems to ask for a next gear very soon (around 3000-3500 rpm), but if you have "faith", it will continue increasing the rpm effortless, and even will sound quieter and respond better at 4200-4500 rpm (where it has its max. torque). This will keep it "awake", and will clean better oil, valves, injection...- And it's not necessary a big pressure in the gas pedal to reach that revs... (maybe it's more easy to control this with a manual gearbox).

In my case, after a short period of constant higher revs than usual (some miles between 4500-5000 rpm for instance), the engine sounds better, the iddle is more stable, and it seems more nimble. I feel the car quicker and more enjoyable when I push it to 4500-5000 rpm before changing to 3rd or to 4th gear

According to the official figures, 280 SL reaches 170 hp at 5750 rpm, and max. torque of 24.5 mkg at 4500 rpm, so your engine is more comfortable changing gears at 4500 or some more revs than at 3500 rpm (above all, when changing from third to fourth gear)

Regards,

* Two friends from the MB Club Spain, 230 SL and 280 SL owners, usually drive their Pagodas at 190-200 km/h (118-124 mph) on the highway without problems... and it's really amazing for the rest of the drivers!  

Albert de la Torre Chavalera
Barcelona (Catalunya/Spain)
Feb.'64 230 SL Euro 113042-10-002432

[ja17]

Hello Guys,
A little story you may find of interest. Years ago I bought a healthy but used M130 280-SL engine with 160,000 miles on the odometer. I removed the cylinder head and reconditioned it and re-assembled it with a new timing chain. I installed this power plant in a highly modified Mercedes W114 sedan prepared for FIA and SCCA Pro Rallies. This car was run hard for about seven years in these events (usually about two or three a year). Some events were  800 miles of tortuous competition. The car frequently saw speeds over 100 miles per hour often on gravel or dirt forest roads mostly at night in all kinds of weather. Rpms 4,000 to 5,800 was common and sometimes into the red. The Mercedes occassionally crashed or rolled but always ran without failure. The closely monitored the engine during these events with added oil temperature guage, fuel pressure guage and vacuume guage. Eventually the little rally car rusted out from having the its belly "gravel blasted" down to the bare steel during these rallies. Before sending the hulk to the crusher the M130 engine was removed, and is now serving time in a Mercedes 250-C (W114) in Virginia. The engine was aways maintained well. Needless to say these M130 engines gained my repect and confidence.

Sorry Cees, I don't know how we got so far off topic!


Joe Alexander
Blacklick, Ohio


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[Cees Klumper]

That's ok with me - I like this story a lot better than the one about the microswitch (whose responsible for that anyway?). When I started reading your post, I thought you were talking about the 'microbeast' coupe that probably has a comparable history to this rallye car? Was it 0-60 in six seconds, with an M130 engine in a Mercedes 250 CE body?

[Longtooth]

O.K. I'll bite... what's this micro-switch / kick-down business?  I have a '67 250SL 4spd...

I gather it's something used on the auto trans W113's to shift the auto trans down a gear faster than would otherwise occur... reving the engine activates a solenoid which activates something in the trans to 'kick' the gear down one?  The micro-switch does what?  I also gather this micro-switch is what actually activates the solenoid?

BTW, I drive constantly at 4K rpm, shift between 4K & 4500, tending toward the latter, but don't often find opportunities to cruise at 5K or more... now and then, but at best only for a few miles at a time.  With the budget crunch here though (CA), the CHP is getting a little more scarce so I suspect the next year or so I'll find more opportunities for 5K+ rpm travels.  Hasn't anybody ever noticed that their W113 feels more responsive, smoother, and more at ease at 4K and more?  I mean you're cruising just below max torque so putting a little more foot on it at that speed is the sweet-spot for this engine.... where it's designed to work.  I mean 80 mph (~ 130-135 km) is the lower end of the normal 1960's autobahn speeds ... and to be caught in an SL on the autobahn in the slow lane or being caught up to by anything other than a 600 (maybe a Porsche) in the '60's in the fast lane on the autobahn was tantamont to being the biggest woose (wus?)in Deutschland.  Didn't happen.... I was there ... driving my 544 B1800 Volvo.... I should have been so lucky to have an SL at the time let me pass them, and I drove 100+ mph (160+ km) everywhere at the time (I was 17, 18, & 19 so didn't know fear, just thrill and ego).   It was a pride (or ego) thing, but the pecking order was Porsche's, MB's (SL's and 600's), BMW's, then everything else, AutoUnion's (predecessor to Audi) 2 banger taking up the rear along with the French Deux Chaveau.  The Masarati's and Fararri's were in a world of their own.... nobody even tried to keep up with them if they wanted to stay alive long.  

BTW, the high beam flash was a good thing.... you can't hear a horn of a car doing 140 mph coming up behind you in time to do anything but you can see those flashing headlights in your rear-view mirrow coming at your rear from a couple km's away and if you acted quick you could get outtatheway in time.

Unlike the holier than though speed limit drivers in the US fast lane trying to show you they're just 'obeying the speed limit... and will enforce it on you too' types, in Deutschland at the time, and most of Europe (exception was Southern Italy), it was considered bad manners and downright rude to keep a faster vehicle from getting by you on the left... if you were driving a Volvo at 110 (flat out), and could make out an MB Star in your rear view mirror at all... you were holding them up.  Move over and stay outtatheway.  Also BTW, nobody passed anybody on the right.... that was considered even worse than holding up a faster car.... so you drove in the left lane with one eye on the rear-view mirror and the other watching where you were going....or you slid over to the right lane so you could use both eyes on the road in front.  Generally speaking everybody drove in the right lane until they needed to move to the left lane to avoid hitting the slower vehicle in front.  But you never just moved over to the left lane without spending a lot of time looking back to make sure the 150 mph MB or Porsche wasn't coming on in that lane.  Profuse use of left turn signal to let anybody you may have missed seeing have enough time to flash their high beams to let you know they were coming on faster than you could get into the left lane and back to the right lane without making them slow down.

Those were the days.  But that also included the downside ---  massive autobahn accidents involving lots of dead when this kind of driving also occurred almost without speed reductions in heavy fog.... 50-60 cars would end up piled one on the other  in a 5 minute period since you couldn't see more than 100 yds but were still going 100+ mph 'trusting' the slower cars were in the right lane.. either trust or a 'bierchen' with lunch.

Longtooth
67 250SL US #113-043-10-002163
95 SL500

[Ben]

I never used to take my 230 over 4,000 'till I rebuilt the motor. Once it was run in I drove the way I needed to.

I find that after a good motorway blast at 4,500 to 5,000 it runs sweeter and idles perfectly. Recently I was about 40 miles from home and heard my mother had a car crash, t-boned by an S500, she was okay thank God. Anyway I did a U-Turn and headed back on the motorway and held it just over 5,700RPM for about 10 miles, passed everything ( in fact everything just got outta the way) and the speedo read about 122mph, so I guess it was doing about 110mph.

The car ran so sweet for the next few days. I reckon if you know your motor is good then rev it. If its an unknown then nurse it !

Regards,
Ben in Ireland.
'64 230SL 4sp.

[ja17]

Hi Cees,
The "Microbeast" had a similar history. This time a W114 250-C (coupe) was modified for club autocrossing. A M130 engine again was used with a reconditioned head. The engine was left stock. Many other parts from the old extinct rallycar were used also. The body was lightened and sticky racing 16 inch 255 tires were installed all around. With the light weight and a four speed transmission, the little coupe would go 0 to 60 miles per hour in six seconds flat! Leaving the engine stock but removing weight made the car very fast but left it durable. It would just about burn the tires off the rims in first gear. We used a diesel 4:09 rear end. I used this car for many years also, mostly in competition. We built several of these conversions for different people. They were amazingly durable and competative.
I always made sure these engines had good oil pressure, fresh oil, good compression, a good timing chain and timing gears before pushing them hard!

Joe Alexander
Blacklick, Ohio

[n/a]

Cees,

Have you had a chance to photograph that microswitch yet?  Am still unable to locate mine?

Thanks!

David - VA

[Cees Klumper]

Hi David - no I did not get that chance yet. Mine is on the firewall, sort of behind the brake booster. But on most Pagoda's it is on the venturi body (the stubby aluminum widget that the thick intake air hose connects to, that is bolted onto the intake manifold). The switch is a small one (so truly micro). I will try to take pictures tomorrow, when I get to drive the car again first to work, then to Peter van Es' (member here) house.

[n/a]

Cees,

Well, apparently my microswitch is ok.  I thought I had no kickdown availability when flooring the car.  However, after inspecting the switch under the pedal, I found that it has a distinct detente' when pushing it down.  In other words it's not a smooth transition when depressing the switch- there's like an initial resistance to overcome then when you push harder it clicks in.  Is this normal?  Or it it supposed to be smooth button to push?

Daggone it, I've been so concerned about not having passing gear ability that I've forgotten whether the microswitch is what some say makes the tranny shift smoother.  SOme have stated that one the microswitch was replaced or fixed the tranny shifted smoother.

Thanks for your help!

David

[Cees Klumper]

Here's the photo of the switch on the firewall. The bolt is what I had to do to fix mine, the usually is a bolt there, but it looks different, much skinnier:

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And here's a photo of the throttle (venturi) body, where the switch is on by far the most cars. You can see the two bolt holes where the switch is attached to the throttle body:

Download Attachment: venturi.JPG
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1969 280 SL automatic

[Naj ✝︎]

Can I go a bit off topic here?
Ref: Cees's picture of the venturi:
On manual transmission cars where no microswitch is used on the venturi, should there be a blank cover - using the two bolt holes?
My 280 (manual transmission)venturi looks like the one in Cees's picture but the area is cleaner than the rest of the venturi and it seems like something is missing???
naj

naj
'Kloines Scheisserle'
65 230SL
68 280SL

[Cees Klumper]

Naj - I have not seen a cover on a venturi without the switch installed. Don't think there should be such a cover. What exactly do you mean by "the area is cleaner than the rest of the venturi and it seems like something is missing?"

[JPMOSE]

How does one test the microswich (mine is on the firewall) to see if it is working?

What are the symptoms of a "dead" microswitch?

Best Regards,

J. P. Mose
1968 250SL

[Cees Klumper]

My understanding is that when the microswitch is operating properly, the 3-position solenoid should move when you depress the accelerator slightly.

Cees ("Case") Klumper in Amsterdam
'69 white 280 SL automatic