How Powerful???. - PeachParts Mercedes-Benz Forum

#1 10-03-2004, 12:30 PM

Got my 73 280SE 4.5 back finally Friday after about 3 months in the shop between mechanics, paint and then back to mechanics..Finally got to drive around town yesterday and was a bit disappointed...seems very sluggish and was running hotter than I expected. I guess I thought from standstill if I floored it it would really take-off but just slowly cruises away and up San Francisco hills it was really laboring..also after warm-up it went just about the 175 notch..but then in traffic it climbed up to the next notch and never really came down again. It was not that warm of a day in San Francisco. I feel like they must really have the timing off or is this engine just not peppy? Seems to me for an 8 cylinder is should have some guts..More concerned about the temp at this point as I was nervous the whole time and watched the gauge constantly..just wanted to get it back to the garage and will take it back into the shop tomorrow..Any and ALL OPINIONS greatly appreciated. Thanks,
Ed

300SDog · #2 10-03-2004, 01:27 PM

Serious chemical coollant system flush should be annual event. What does the radiator core look like when you open the cap? Passages get narrowed and clogged with scale and crud.

It's tough to find a shop that does a competent job with coolant system flush because it makes a mess. Or better yet, have the radiator boiled at the radiator shop.

There are other items such as fan clutch, thermostat and aux electric fan that effect the coollant system - but the radiator is the biggie. And the radiator on your 280SE is 30 yrs old.

#3 10-03-2004, 02:09 PM

Thanks Dog..I always felt the radiator should be pulled and boiled out...Car sat for a couple years without being driven...Still curious what you all think about the power issues..My 280SL 6cylinder was so zippy..I just expected the 8 to snap your head a bit when you punched down the gas even from a stop.
Ed

psfred · #4 10-03-2004, 05:41 PM

The timing was set with a defective or unplugged vac retard, and is hence 12 degrees late -- all you symptoms match.

Will burn SERIOUS fuel, too (10 mpg).

Get the timing and mechanical advance checked -- that M117 would spin the tires on takeoff!

Peter

#5 10-03-2004, 07:24 PM

PSFRED..what you say makes so much sense..took it out today and just drove around the city a bit..it is much cooler out today so the car didn't run as warm but still so sluggish and I had just filled it a couple days ago and it's down a quarter of a tank..I will take it back to the shop in the a.m. tomorrow and take a print of your post about the timing...Thanks again,
Ed

j9fd3s · #6 10-03-2004, 08:51 PM

way retarded timing might also cause the running hot

300SDog · #7 10-03-2004, 11:08 PM

Hell yes, it sounds like Peter nailed it..... Distributor advance problems causing the engine to run retarded.

You've got vacuum advance line that pulls a diaphram and centrifugal advance too. Centrifugal is usually a question of just keeping it lightly lubed under the dizzy. Vacuum advance problems can be just a cracked connector or elbow, dislodged or crimped vacuum line.

The vacuum system even on primitive MB's is sacred ground. I would seriously consider getting a multi-color hobby shop paint set and marking exactly where each vacuum line goes.

#8 10-03-2004, 11:20 PM

You guys..I can't thank you enough for all this..I love the cars..drive em but count on the mechanic to do his thing..I'm good at cosmetics and writing the checks, but my knowledge is sadly lacking in the mechanics. I rely on you to sort this all out..will post some pics if I can figure out how. This has truly been a labor of love and dollars but the car looks spectacular, just want it to drive that way too. Still working on the oxidized trim..since the "green magic thread disappeared, today I used 0000 steel wool and Wenol creme and that improved it alot, any other help that way is appreciated.
Thanks again,
Ed

#9 10-06-2004, 02:20 AM

Hey..
Took the car back to the shop with a printout of all your comments ..Picked it up today..you step on the gas and it burns rubber and snaps your head back...runs cool and is so so fast..thanks all..
Ed

Dana B. · #10 10-10-2004, 11:22 PM

That's great! Love a happy ending. Can you post some pics?

WANT '71 280SEL · #11 10-11-2004, 07:20 PM

Was Peter right with the diagnostic? Please tell us what was wrong.
Thanks
David

#12 10-11-2004, 09:19 PM

Thanks for the inquiry "Want 71 280SEL" The car is alot better. Peter's suggestion did make a difference. I think they had the timing way off. It definately has more pickup from start-off and is running at the right temperature but I still feel something is off. I've thought of trying a different shop at this time. I've just gone to same one for years. When I got my car it had been sitting a long long time. It was blowing alot of smoke. My mechanic said there might be a problem with the valve seats..he drained and refilled the car with synthetic and that seemed to cure most of the smoke. Every once in awhile it will put out a big puff of it and then it's gone for most of the time I'm driving it. He said I might need a "top engine" rebuild but to drive it for a bit. I still have not been on the freeway but just around the city driving. Maybe cuz I've just been driving an 8 cylinder newer Land Rover lately I'm not used to the slowness of the 280SE but it just seems to be working so hard and if I'm cruising along at about 40 and push the gas to the floor it really doesn't do anything, just slowly speeds up. At this point I'm really not sure what to do. Engine has great compression, runs cool now..leaks nothing so I'm not sure what is the next step.

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WANT '71 280SEL · #13 10-12-2004, 01:26 PM

Is it downshifting when floored? my friend's kick-down feature is broken so he has to manually downshift it to really take-off.
Thanks
David

Tomguy · #14 10-12-2004, 06:31 PM

Thing is, if it's in 3rd and you floor it going up a hill, it'll shift into 2nd and it wont be that big of a difference. If you REALLY want to go, pull it down into first until about 55.

Floor it at 80. If it doesnt shift into 2nd and throw your head back, and rocket to above 100 before you realize it, the kickdown is bad. If it does kick into 2nd but doesnt push you back in your seat (and it should, believe me!) then something else is amiss...

Check the mechanical advance. This is something you can easily do yourself. Pull the distributor cap off (it's held on by 2 clips, just push back on the tops with your finger). Try to move the rotor clockwise (don't force it!) - if it doesn't "easily" move or, if you let go after doing so, it doesn't spring back, you need to clean your mechanical advance mechanism. If you can turn it CCW but not CW at the beginning, this also means you have no mechanical advance, but make sure to turn it fully CW again or else YOUR TIMING WILL BE WAY LATE!

To put the cap back on, make sure it's straight above, put it down squarely (not at an angle, you might break the carbon contact) and then reattatch the clips (I find pressing "in" to the dizzy at the center of the clip makes it snap on quite easily).

If your mechanical advance IS screwy, I can tell you how to easily clean this yourself. You will need to retime it afterwards, however, so if you dont have a timing light, go back to the shop when you're done.

#15 10-14-2004, 09:52 AM

If it turns out I have to replace the valve guides and seals, what kind of money should I be figuring on spending for this?
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