I finally got around to adjusting the valves in my 1980 240D, and man was it a job!! It had been at least 75,000 miles because Ive owned it that long. I dont know if the previous owner had done anything. Yeah I know, beat me with a wrench. I have heard that they should be adjusted every 15k, so I figured I better have a look because last winter the car didnt start easily(interestingly, the car seemed to only fire on one cylinder on startup. The data below shows why.)I purchased two angled wrenches and a shorter wrench which supposedly made the job easier. I bought a valve cover gasket, and some mercedes fuel injection return hose, because I figured I might as well change the hoses while I was in there.
Well anyway, when I finally got the fan ,fan shroud(I had to take those off to get to the crankshaft nut to turn the engine), air cleaner(the pcv hose was loose), and the valve cover off of the engine,I inspected the gap of the valve lashes and knew it needed some work. I got my wreches out and started to adjust that distance(I never used the shorter wrench). My son worked the feeler guage and I adjusted. The pre-job gaps for the intake, in no particular order were 0.000in, 0.000in, 0.000in, and 0.004in. They were all supposed to be at 0.004in. For the exhaust gap, which was supposed to be 0.012in, the distances were 0.010in, 0.008in, 0.008in, and 0.006in. Way off. So we adjusted all 8 of them,double checked them and then put the valve cover on with the new gasket. Then we put the throttle assembly and the hoses on...that was fun. We then put the air filter back on, repairing the loose pcv connection. Then the really fun part...putting the fan and shroud back on(it was also hard to get it off). I had to loosen the alternator to do that. Well the job is done and it will be interesting to see if anything improves. The car seems to start a little faster and I'll check the fuel economy next week. Its been getting around 26mpg, with mostly highway driving. The reason the car last winter seemed to want to start on one cylinder was because I only had one cylinder properly adjusted.
I only have one question, when I was putting on the vacuum hoses to the top of the cover, I noticed that the "Y" rubber connector seemed to have a restriction in it. Not knowing if this was right, I took a coathanger and pushed the restictor out of one of the Y legs. Does anyone know if it is suposed to be there and on which leg of the Y.(What does the restrictor leg of the Y connect to)?? Without it in, I drove the car and it shifts OK. The restrictor has a pinhole in the center and it slides tightly into the rubber Y. Thx for any imput. By the way, the whole job took us 6 hours.

Joe

Is this a 123 series 240D? If it is, I'm shocked that you had to remove the fan to turn the engine. I simply use an injector socket and a half inch ratchet on the crankshaft bolt, and it fits perfect. I adjust them without removing ANYTHING but the valve cover. I even do the same thing on a 300D, although my hands look like they've been through a meat grinder afterwards because the fan is in close quarters on the five cylinder.

The third wrench is not totally necessary most of the time, but occasionally you will get a stubborn one where it is indispensable.

I'm sure the Y, should connect vacuum to all three hoses.

Job well done,

Larry, Donkey

Larry...As far as I know it is a us model 123 240D. With the fan shroud on, I couldn't seem to get anything in there to turn the nut. (I used the injector socket also) Part of it may be that I didn't know exactly what I was doing. Did your cars all have the fan shroud on them?

Maybe I should have turned the PS nut and the cam nut together, and maybe the fan, and it would turn on its own, without having to take the fan off. That was a real pain.

Joe

I use the injector socket and a 1/2" drive socket wrench and can get to the crankshaft bolt without having to remove anything ('85 300D). I never actually "see" the bolt but can feel around until the socket is on it. Just don't forget to remove the socket wrench before trying to start the engine.

__________________
Jim

Roger on removing that ratchet before starting the engine. If you don't, you'll get to remove that fan and many other parts aftwerward.

Yes my cars have the fan shroud, you have to reach under the fan to turn the ratchet.

Good luck,

Hey guys, why didnt you turn the engine with a srarter switch using the starter? Follow the wires from the starter up to the block with three wires on the wheel well. Then jumper the two outside terminals and "walla" over turns the engine. The next time you adjust your valves it will take you 1/2 the time it did this time whether you do this or not. They call it a learning curve. DB

What "Y" connector did you monkey with? I put the "Y" connector that connects the vacuum supply, vacuum valve and the auto transmission on wrong and I ruined the transmission. This was on a 300SD. This "Y" connector is supposed to have a restriction and it should be marked by a plastic ring on the outside to denote the leg with the restriction.
P E H

PEH

The "Y" I messed with is the one you're talking about. It sits on top of the valve cover and connects the vacuum supply on one of the shorter legs, the transmission on the other shorter leg, and the longer leg of the "Y" goes through the vacuum switch on the valve cover to the injection pump throttle position vacuum release. The more throttle you give it, the more vacuum is released and the vacuum to the tranmission goes down.

I need to know in which leg of the "Y" the restriction goes. I'm almost certain this Y doesn't have a plastic ring anywhere, but I'll look again.

Thanks for any help

The restricted leg of the "Y" connector goes to the vacuum supply. The other 2 legs go to the vacuum valve and the transmission. There must be a restriction in one leg otherwise the vacuum valve would not regulate the vacuum to the transmission. I learned about this from the rebuilder that sold me the rebuilt transmission.

The rebuilt transmission I put in works so much better than the original, it was almost worth the cost, ~$1200, to get the updated transmission.
~~~~~~~~~ P E H

PEH

Yesterday, I put the restrictor in each of the 3 legs to see what the effect was on the vacuum to the tranny. I do agree with you that the restrictor should go into the line supplying vacuum, but the problem I have is the vacuum drops to 5 when the vacuum switch on the valve cover is moved off of idle, and doesn't seem to vary much.

I measured this months ago, and I would get 21, then 9 when off idle and then it would smoothly go to zero with throttle position. Maybe I have a leak somewhere. I need to do a little more checking.

I'm still having trouble being able to get the throttle pedal to contact the kickdown switch. I've tried adjusting the linkage, but can't seem to get it any better. Do you have any thoughts on that.

Thanks
Joe

JOE,

I don't have any information on what the values of the vacuum should be when varying the vacuum valve but it should get lower as the accelerator is depressed.

When I connected my "Y" connector wrong, the transmission was getting full vacuum all the time and that is what caused it to slip or so I was told by the rebuilder. The trans had ~190,ooo miles when it first slipped and went another ~10,000 miles until it got so bad I had to replace it. I connected the "Y" connector wrong in TN and it didn't slip until I got to OR, about 2500 miles later.

Maybe you can attach something to the bottom of the accelerator pedal to contact the kickdown switch or raise the kickdown switch.

P E H

PEH

We must think alike. I did attach something ( a medium binder clip off my desk)to the throttle linkage and it works pretty well. It's a lot nicer having the ability to get it to kick down from 4 to 3 with the throttle instead of manually operating the shift lever.

I have found out that the 3 way vacuum valve on the valve cover is leaking. With a vacuum source of 20 on the input, and plugs in both of the other lines, it drops to about 9. It is leaking through the actuator pin o-ring.

So I have ordered that part, and the Y connector, from fastlane and will be "playing" with it more. My vacuum is so low because of the leak, that I shouldn't be hurting the tranny, at least I hope. I guess you had 20 on the modulator all the time...probably not a good thing.

I will follow up after installation of new parts. Thanks for the input, as usual.

Joe