From reading in the forum and talking with others I have been told to check the exhaust butterfly/perheat valves under the carbs. Well mine are stuck.. What I do not know is if they are stuck open or stuck closed. Is there a way to tell without completely removing the manifold, or perhaps a way to unstick them? It would appear that I could get at them from under the car but not sure if I should just pound away or not.

Thanks

Ron

Looking at the M130V parts diagram (Pub 12815, table 8 - M130V, group 14), the inside diverter is shown as vertical, which would be diverting heat upward to the carb plate and over the flap then back down toward the manifold outlet, when you want heat, holding against exhaust pressure. Then, as pressure overcomes the (relaxing) coil spring, the larger/lower half of the inner flap rotates outward and smaller/upper half inward; the combination closing off the pathway along the underside of the carb and fully opening up the exhaust's exit path, beneath/inside the flap. This should prove to be consistent with the winding of the spring(s) - but verify:- look at each spring's relationship to the pin vs the shaft - try to visualize that spring as it "relaxes" when it heats up - "opening" or loosening the coil's wrap - and permitting the bottom of the flap to move outward, away from the block. Some shafts are "damped" with a weight, some with a friction spring on the opposite end of the shaft from the coiled actuator spring.
See the thread on same, about the 220Sb...
W111 220Sb Exhaust manifold "preheat regulator"
W111 220Sb Exhaust manifold "preheat regulator" ?
- try soaking the flapper/damper weight shaft with PB Blaster where it goes through the bearing holes in the manifold, knocking/tapping the shaft around a bit on both sides (not TOO hard, please), and grasping the damper weight (or end of shaft, if has friction spring) and trying to turn it back and forth. It should move pretty freely, to operate properly under the direction of the coil spring vs exhaust pressure. Try to not hit the (rusty) pin which holds the (rusty) outer end of the coil spring from rotating - if that breaks off, you're truly S-O-L - it would have to be drilled out and replaced, unless you're really good with JBWeld.
If the shaft remains very stiff, and you manage to get it turned all the way "open" to its stop, consider leaving it there, for summer; then closing it just part way, in winter - say, maybe a twelfth of a turn (effectively about 1/3 closed)...
If it's truly "frozen", it may take some heat from a torch, plus kerosene-type rust solvent, to free up the shafts. Otherwise, you'll have to pull the manifold pair, take the intake up off the exhaust (another fine challenge - speaking of rusty bolts and nuts), and access the flap, to loosen/open.

Good Luck!

Stan

__________________
stanbabu@3bubbas.com
59 300d
65 250SE/Cpe
70 250/8
72 250C
78 280CE

Mine were rusted solid. I pounded them completely open and have left them that way. I have yet to see one on any vehicle I've worked on to have those flaps operating. I believe my weights are at the top (clockwise is open when looking from the front of the vehicle).

__________________
Adam Lumsden
(83) 300D
Vice-President of the MBCA International Stars Section

Ron:

You need to lift the weights, they rotate so the weights move up toward the engine block. These are a PITA to keep operating. The PB Blaster would be a good choice to free them up, also Liquid Wrench. It has a bit of graphite in it. Try to avoid the urge to use a pry bar, this can bend the shaft...ask me how I know this.

Once they are working free you need to keep them free and this is the tricky part. Oil will simply make them stick so you need something resistant to high temps. I have used a heat valve solvent I got from Chrysler years ago. You might try a truck shop for something similar, or a Catepillar dealer or other tractor dealer. Lately, I've used a home brew of liquid wrench and Never-seez moly paste. I put a small amount of Never-seez into a pinpoint oiler with the Liquid Wrench and then I squirt it on the shafts almost every time I open the hood. Shake up the oiler before you use it to suspend the moly in the solution. Works for me.

It really helps to have these working right. The car will stumble when cold and have poor driveability if they are just left open. But, if they stick closed, you will trade the cold stumble for hot weather stalling and warped carbs...sounds like the perfect lose-lose situation doesn't it?

Good luck,

230/8

Well they are stuck, lots of liquid wrench, a bit of tapping and they do not want to move. The back of the weights faces the block (where the cutouts are) and the springs are relaxed. Still not sure if this open or closed. Guess that the manifolds will have to come off.. Finally got it running well after a carb rebuild, abet with a temporary accelerator pump fix on the rear carb. Even got the jury rig removed for the chokes. All choke relays and speed sensors now work correctley. Timing correct etc. Will wait awhile before removing the manifolds. Tranny fluid change next.

Thanks for all the help

Ron

Ron:

You can easily tell if the valves are open or closed. There is a small steel tab screwed to each weight that rests against a pin protruding from the manifold. This tab acts as a stop to prevent the valve from travelling over center too far and getting jammed. If the tab is resting on the manifold pin the valve is in the closed position. You lift/rotate the weight up to raise this steel tab off the pin which opens the valve. Range of travel from valve closed to open is about 80 degrees for the weights. There is no need to remove the manifolds to inspect the valve position. Be patient and use plenty of penetrant on the shafts. Once they are rusted shut it nearly takes an act of God to get them open, but they will free up and open up after you work hard enough.

230/8

Sounds familiar working like a mad man to free one myself. Acethylene/oxygen did free up the one side but the other side I only managed to move the bushing.... Argh....

Karsten

From 230/8's description mine are stuck closed. At least the tabs on the weights are about a 1/4" from the pins. The springs however are relaxed. Hopefully the car can be operated with them in this position.

Ron

Don't know how a 230/8 compares with 250/8 M114 engine, but suspect the manifolds are very similar; I find approx one full inch of arc between stops on my (still free) weights, at their outer perimeter (In other words, I can pull "out", away from the block, on the bottom/notch corner, and pull them up about an inch, off the rests. Cold, and against spring resistance, I conclude that their "rest" state is closed/heater setting; so if yours are 1/4 inch off the pin, they're only about 1/4 to 1/3 "open" - e.g., heating the exchanger plates more and somewhat obstructing the exhaust flow; however, if it's running allright, you're probably fine - looking at the cross-section, it appears that these buggers actually do more to keep cold vapor from condensing out in the intake manifold than anything else...and the exhaust flow just has to go "around" (over and under) the flapper rather than all under it and smoothly out the manifold outlet.

I can't speak to the alleged "warping" of carbs from heating the bases more than normal (since the flapper isn't "shielding" the exhaust flow from the exchanger base) - especially with the thick asbestos gasket between the manifolds' metal castings.

In the meantime...keep sprayin' and tappin'...

__________________
stanbabu@3bubbas.com
59 300d
65 250SE/Cpe
70 250/8
72 250C
78 280CE

This one is a 130 engine, not sure of the differance either. The car is now running quite well after a carb rebuild, fixing the chokes and the emmissions setup. Had to remove the rear carbs fast idle screw, don't think it should have had one as the car is a 71 with the delayed rear choke circuit. The car has been this way for several years, and the carbs were not warped, I checked them when I rebuilt them. Getting ready to travel for work again so don't really want to dissassemble the manifolds right now. Will keep spraying and tapping perhaps like alot of things on the car now that it getting driven perhaps they will wake up again.

Ron

Very similar engines - the M130 was same stroke but a larger bore, and I believe the cylinders were respaced. But when I rebuilt my 114, I replaced all the single-chain gear with doubles for a 130 (my parts guy knew they'd fit, and I was looking for a double chain); and they sure LOOK the same. Actually, I went quite a few years not realizing that the W114 250C's AND 280C's BOTH had 2.8L engines, with the 70-72 250C's being M130's (as opposed to the 250 sedans' 2.5L M114's) and the 73-77 280's and 280C's being M110's...

__________________
stanbabu@3bubbas.com
59 300d
65 250SE/Cpe
70 250/8
72 250C
78 280CE

I removed the manifold forced them into a position to avoid carburetor over-heating. Coldest temp here is 25 F, so I spend another minute warming up the car.

__________________
1970 280S M130 engine- good runner
1971 250 M130 engine- #2 rod bearing, gone
1971 280SE (blown engine,parts car)
1977 German 280S W116-only 33 years old

I think one of the key elements to keep the valves working is to replace the thermo springs when they are in need. I just picked up a couple of new ones at MB. They are cheap, less than 2 USD.

Karsten

Edit: Looked at the wrong spring on the invoice. The thermo springs are around 10 USD each.

Concur fully on keeping the thermo-springs alive and well (the $10 ones) - and the $2 ones were probably the little "keeper" clips (000 137 010 201) that fit between the ends of the axis and the pin, over the thermo coil springs themselves (115 143 00 10) . There is also one other little spring (180 140 01 27), which is screwed/staked to the weights, to absorb "bounce" and shock and reduce rattling noises, when they rest on their stop pins.
When I went to check mine to see the travel, the springs are still shiny-ish, and the flappers still moving very easily and properly, after sitting for seven years with only an occasional start to move around the yard or to escape up the road to higher ground during hurricane flooding -
So...if you can get them freed, blast the crap outta the shaft bearings and keep them lubed with some high-temp lube, and renew the springs, they may be worth having in place.
There is apparently a mod, however, that does away with the weights and uses a friction spring instead for stability, while the thermo spring and exhaust pressure work against each other to position the flap -

(Knowledgeable comments/amplification, anyone?)

See the illustrations in
http://www.detali.ru/cat/oem_mb2.asp?TP=1&F=114010&M=114%2E920&CT=M&cat=034&SID=14&SGR=001&SGN=01
for a 250/8 M114;
http://www.detali.ru/cat/oem_mb2.asp?TP=1&F=114008&M=180%2E954&GA=722%2E105203&GM=716%2E002&L=760%2E101++++++++++++++765%2E700&CT=M&cat=033&SID=14&SGR=001&SGN=01
for one of the 230/6 M180's;
and
http://www.detali.ru/cat/oem_mb2.asp?TP=1&F=114023&M=130%2E923&GA=722%2E104204&GM=716%2E002++++++++++++++717%2E000&L=760%2E101++++++++++++++765%2E700&CT=M&cat=036&SID=14&SGR=001&SGN=
for a 114 250C's M130.

Flappin' along...(thermally speaking)

Stan

__________________
stanbabu@3bubbas.com
59 300d
65 250SE/Cpe
70 250/8
72 250C
78 280CE

I had to move on to a spare manifold, also with stuck valve.
Problem was that the one bushing loosend from the manifold with a stuck shaft in it... Not much to do about it other than cut off the old valve and fit a new....

Karsten