how difficult to do the valve seals on a M110 engine? How are the power door locks on a W116 supposed to work? Are the vacuum locks supposed to engage the balance of the doors when you lock either the drivers door or passenger door? Bob

my book for the 110 is at my favorite machinists shop along with my 110 engine. we looked breifly at that question a couple of weeks ago. the book shows a special tool to compress the spring using the cam as a lever. the little locating clips can be gotten out with a screwdriver i think.

perhaps you can remove them with a jury rigged device.

we were considering whether the valves need grinding or not. if not then maybe not nec to split head. and then can replace seals in a lot less time.

sorry i cant give a definitive answer.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Never done em on the twincam but have done valve seals on single cam m180. Basically its about compressing the springs and pulling the rockers, then removing valve springs and replacing the seals ONE cylinder at a time while lining up each to TDC and hooking up an air compressor to the spark plug hole in order to prevent the valves from dropping into combustion chambers. It took me 2 days to set 12 valve seals on 1965 220Sb - working impeccably slow. The hard part is setting the new seals properly without chewing em up. I used wooden chopsticks to push em in place. Advance/Search "valve seals" exclusive to this forum and you will see how its done, how to find TDC for each cylinder, etc and/or we can talk you through it after you line up an air compressor and valve spring compressor from rental tools. Its not real hard to do, just time consuming if you do it right. And loosing those itty-bitty valve spring keepers is major hazard. You will need a magnet to pick em up, like one of those nut'n bolt magnetic retreiver tools that cost a couple of bucks with telescopic antenna handle.

Air locks can only be triggered up and down in unison from the driver's door. After 30 yrs they start to get sluggish. Then experiment with techniques like revving the engine to lock em all, then quickly running outside to relock the driver's door after waiting long enough for the system to leak any backup pressure, usually 30 seconds after shutting off the engine, so they dont start unlocking when you jump outside. I've used this technique with more than one leakey air lock Benz. Tracking and fixing the actual air lock leaks is royal pain in the ass. Arguably you might be better off going behind each door panel and disabling the entire system making it manual locking instead.

well since the head is off my car, a lot of that would be simplified.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

The autobahn animal 280E? I still say you should sell the 5 spd tranny with driveshaft to me for my 240D. Even with 4-spd the 280E will have a top end that never quits. You probly wont get into 5th below 95mph anyhow, but for me it would help the 240D do better than 85.

Forget it Dog! Just get a Euro speedo calibrated in metric! It'll make you feel better when the needle pushes on 120.

I see that the camshaft housing that holds both the cams has to come off the motor...is this a big deal? A generic valve spring compressor will work?
Thanks for all the input.....When you say the door locks can be actuated from the drivers side door...how are they actuated? What creates the vacuum in a W116 car? I dont see a supposed vaccum pump...its not the air pump? Bob

i dont think a generic will work without modification.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

i just got off the phone with my machinist and he said removing the valve assemblies is a triple mother F#$@^&R. so probably using anything other than the mercedes sanctioned little trapeze thingie will probably meet with frustration.

he also said it took he and his son, who are both very skilled and experienced on heads, two hours together to put the valves springs and seals in. the rockers are not even in the equation yet.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

To answer the original question. It is a big job because you need to remove the cam box, which means pulling the chain rails and the intermediate gear out, and removing half of the head bolts. When you are done with that, you are about pretty close to having the head off, so you might as well do the valves and guides. And replace the chain.

I have never heard of just replacing the seals doing much good. I assume that you are starting to use significant amounts of oil.

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Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

Chuck, the car sat since 1992. I got it running for a very brief period in 1997.
I now have it running on the road. Odometer registers 185,000 miles. The previous owner had some work done on the top end of the motor back in the early 90's.Do not know the extent of what was done. The valves are pretty noisey. I am sure it has not had much run time since the differential failed back in the 1992 time frame. This is how I acquired the vehicle. It is running pretty decent after going through all the fuel stuff. When the motor is cold started there is an appreciable amount of blue smoke until the motor comes up to full temp. It then seems to go away. Nothing on the highway...rings must be good. I guess the correct thing to do is a leak down test? Have not checked the compression since I acquired the car. I do not know what the oil use is since I have just recently gotten the car driveable. I will monitor closely from now on. Bob

One would have believed from the service manual that the cam housing fell off when looked at. I figured it would be a bit more involved than I was led to believe. Trying to decide if I should wait until winter...if the car continues to run alright then do a valve job....If the seals are that involved why just do the seals. What are the chain rails...I assume you are speaking about the timing chain rails. How many bolts into the block are there on the cam housing. How do you loosen up the chain to the point that it comes off of the cam gear? bob

Depending on your year of M110 there are many with a mechanical vac pumps on the head that have rubber diphs in them that either rupture or get cracks and pinholes in them causing smoking and also the Vac modulator on the transmision can cause your problems , I do not reccommend the gear removal unless you intend to pull the A/c compressor and all the stuff on the side of the head where the chain tensioner is as it is spring loaded and once you give it slack you are in a pickel . You may need Valve guides to really correct the problem but at the age of your engine and the service records you have it is guesswork with out a teardown .Try the things I mentioned for starts .

do you have a picture? I have been all over this car and have yet seen something like a vacuum pump? Bob

What you say here reminds me the m110 has self-torquing valve adjust bolts instead of a locking nut and adjuster combo. And these self-torquing adjusters often wear thin in the threads then causing the rockers to come loose and make a racket.

First things first, why dont you check valve adjustment this weekend? Its an easy job and doing the process yourself will tell you condition of the self-torquing valve adjust bolts. They should be at/near 18-20lbs torque each to turn. They cost about $35 each in parts to replace. And its the kinda thing that ordinary mechanics would overlook unless they know they're there.

Meanwhile to find the vac pump follow the air hose that feeds the power brake servo, but your 116 might not have one. They varied in this.

And pulling the camshafts & carrier is NOT that bad, even me the dummy has done this in junkyard taking almost an entire afternoon. But for the sake or replacement on the same engine you want to paintmark the sprockets to stantions and the chain to gear teeth too, plus TDC the engine just in case. Then just knock off the gears with rubber mallet as evenly as possible one at a time, thats what i did. Trick is to keep tension on the chain with bungee cords so it doesnt skip teeth on other sprockets down below when you pull the carrier and camshafts over it.