Newest addition - PeachParts Mercedes-Benz Forum

lunchbox · #1 02-27-2009, 04:10 PM

Hey all,

It's been a while since I've frequented this site seeing as I've had very few problems with my W108 daily driver, but I've managed to find a new project: a 1975 W114 280c, it's quite the little car. You can tell from the pictures, the interior is immaculate and the engine just purrs! (Actually its pretty loud from an exhaust leak)

I've replaced all the fuel lines, checked all the fluids and did everything that typically needs to be done to cars that have sat for an extended period of time (6-7 years for this car). It has the infamous solex 4A1 carb, but it seems to be running great at the moment.

That being said, I have a few questions:

1. There is a pretty bad exhaust leak, and I will need to replace the middle muffler and the exhaust pipe from the front bend to the muffler. I had seen pictures of an SL mercedes equipped with the same M110 engine, and it had 2 separate header type exhaust manifolds that went from 3 to 1 each. This would not only look better than the "log" manifold that is on the car now (i've never seen a setup like this, the exhaust flows towards the front of the car until it bends back up into what i believe was a thermal reactor, but has now been replaced with an aftermarket cat) but I believe it would give the car a much needed extra touch of power in the higher end. Anyone done this swap or have any ideas?

2. In all the factory manuals I've read, it claims that I need to "top off the carburetor with ATF". I really hope no one took that literally, but can someone explain to me what needs topping off and how I go about doing that on the stock solex carb.

3. The A/C is not functional at the moment, and the green indicator light on the dash does not come on when you turn the A/C knob. Would it be alright to remove the belt while I find a replacement? (I have a lot of experience with I-6 engines, and I prefer to have the least amount of parasitic drain as possible)

4. Electric fans anyone? Again, I prefer for there to be as little drain on the engine as possible.

5. I have noticed that according to the temperature gauge on the dash, the coolant temperature is significantly below the middle line (175 degrees if I remember right). Can someone reassure me that this is abnormal (my 280sel 4.5 always runs at 175) I would imagine a stuck thermostat is at fault in that case, which is not a difficult fix I would imagine.

Thanks for all the help!

Sam

wolf_walker · #2 02-27-2009, 04:31 PM

I envy you that radio, and having two less doors.

Mike D · #3 02-27-2009, 04:50 PM

Quote:

Originally Posted by lunchbox

Hey all,

That being said, I have a few questions:

1. There is a pretty bad exhaust leak, and I will need to replace the middle muffler and the exhaust pipe from the front bend to the muffler. I had seen pictures of an SL mercedes equipped with the same M110 engine, and it had 2 separate header type exhaust manifolds that went from 3 to 1 each. This would not only look better than the "log" manifold that is on the car now (i've never seen a setup like this, the exhaust flows towards the front of the car until it bends back up into what i believe was a thermal reactor, but has now been replaced with an aftermarket cat) but I believe it would give the car a much needed extra touch of power in the higher end. Anyone done this swap or have any ideas?

Should be swappable to the pre-cat manifold. You will need the header pipes from a '74 or older.

2. In all the factory manuals I've read, it claims that I need to "top off the carburetor with ATF". I really hope no one took that literally, but can someone explain to me what needs topping off and how I go about doing that on the stock solex carb.

This advice applied to the Stromberg side-draft CD-175's and not to the Solex.

3. The A/C is not functional at the moment, and the green indicator light on the dash does not come on when you turn the A/C knob. Would it be alright to remove the belt while I find a replacement? (I have a lot of experience with I-6 engines, and I prefer to have the least amount of parasitic drain as possible)

No sweat with removing the belt. In fact you'll be safer removing the belt until you have the A/C compressor checked out. Nothing like having an old compressor locking up on you at about 70 mph.

4. Electric fans anyone? Again, I prefer for there to be as little drain on the engine as possible.

I run only electric fans on my M115 and M110's and look at my signature for my location.

5. I have noticed that according to the temperature gauge on the dash, the coolant temperature is significantly below the middle line (175 degrees if I remember right). Can someone reassure me that this is abnormal (my 280sel 4.5 always runs at 175) I would imagine a stuck thermostat is at fault in that case, which is not a difficult fix I would imagine.

Don't trust the temp gauge. Yours is electrical and it could be a faulty sender, a bad gauge console ground or a finicky gauge. Use a manual thermometer in the radiator water to verify your temp gauge reading.

Thanks for all the help!

Sam

My replies are buried in your quoted post.

Great cars and bulletproof engines. I have a major weakness for the W114 coupes.

lunchbox · #4 02-27-2009, 05:39 PM

Fantastic!

Hey Wolf, I've attached a picture of my daily driver for the past 2 years, there's absolutely nothing wrong with 4 doors, especially when the rears are EXTRA long! hahaha

Mike D, that was a lot of very useful information, thank you very much. Do you feel that no AC, an electric fan and the headers would make a noticeable increase in power? I realize "noticeable" in a 130HP motor is 5-10 extra HP, but in my book, that's pretty substantial!

Takernz_30 · #5 03-02-2009, 05:59 PM

to MikeD,

We have the same engine as you have(M115), my car is a'66 200(W110). I install a W201 radiator and W126 expansion tank but I ran with original M115 5-bladed mechanical and I planned to switch to electric fan, what is your set-up on your electric fan cooling system?

Mike D · #6 03-02-2009, 11:14 PM

Quote:

Originally Posted by Takernz_30

to MikeD,

We have the same engine as you have(M115), my car is a'66 200(W110). I install a W201 radiator and W126 expansion tank but I ran with original M115 5-bladed mechanical and I planned to switch to electric fan, what is your set-up on your electric fan cooling system?

Try here for the thread.

Fan Clutch question

Mike D · #7 03-02-2009, 11:20 PM

Sam,

You can check the temp sender with an ohmmeter. The sender provides a graduated ground as the engine warms up.

The temp sender on my '74 280C 2.8L reads 75 ohms at about 175 degrees.

My '73 280 (with a faulty sender) reads 256 ohms and the gauge shows 110 degrees when the engine is at 190 degrees.

New temp senders are only $14 from Phil and Roy over at Fastlane ("and now, a word for our sponsors!").

lunchbox · #8 03-03-2009, 12:00 AM

o wow! if they're that cheap, there's not a real reason for me not to replace it. My symptoms are almost exactly like yours Mike D, because even after freeway driving, my temp gauge reads about 110ish.

Takernz_30 · #9 03-05-2009, 12:47 AM

to Mike D,

Wow!, I imagined that the clearance bet. water pump pulley and motor is about 1/2"

what is your alternator's rating? The alternator in my 200 is 80 amps., is this enough juice to run a 160 watt fan you have?

Mike D · #10 03-05-2009, 06:12 AM

160 watts = about 15 amps peak when it first engages, drops to about 9.

About the same as running the blower fan on "high" or having the headlights on.

I'm using the standard Bosch alternator, I believe 35 amps.

I do use top of the line batteries. Usually a minimum of 700 CCA.

Watts = Volts X amps.

JonL · #11 03-05-2009, 09:21 AM

Nice car, congratulations. I am envious.

Takernz_30 · #12 03-05-2009, 04:51 PM

Quote:

Originally Posted by Mike D

160 watts = about 15 amps peak when it first engages, drops to about 9.

About the same as running the blower fan on "high" or having the headlights on.

I'm using the standard Bosch alternator, I believe 35 amps.

I do use top of the line batteries. Usually a minimum of 700 CCA.

Watts = Volts X amps.

ok, which is much better set-up, 1 16" fan or 2 12" fan? my radiator is wide enough to fit 2 12"fans.

Mike D · #13 03-05-2009, 05:23 PM

Go with the 2 12" fans. You can run one with the adjustable thermostat assembly and run the other one from the existing overheat sender and tie it into the A/C relay.

The only problem with the 2 fans is you would have to lose the shroud. The 16" should fit under the shroud with a little modification.

Sorry about the thread hijack Lunchbox.

Takernz_30 · #14 03-05-2009, 10:45 PM

Quote:

Originally Posted by Mike D

Go with the 2 12" fans. You can run one with the adjustable thermostat assembly and run the other one from the existing overheat sender and tie it into the A/C relay.

The only problem with the 2 fans is you would have to lose the shroud. The 16" should fit under the shroud with a little modification.

Sorry about the thread hijack Lunchbox.

Mike D,

I inquire about the engine elec. fans from an auto store that they don't have the 12" fans anymore, they have only 10", the brand was Sanden(Japan). But I passed by a used parts store and I found a 14" electric fan from a Volkswagen(Caravelle or the new Bettle). I tested it and WHOA! it's powerfull, the motor is about 4" long 3" in diameter w/ no housing or bracket, then I bought it for PhP600(about US$10).

All I have to do is test fit in the car for clearance,fabricate the bracket with aluminum, welding w/ TIG.

Takernz_30 · #15 03-05-2009, 10:45 PM

Quote:

Originally Posted by Mike D

Go with the 2 12" fans. You can run one with the adjustable thermostat assembly and run the other one from the existing overheat sender and tie it into the A/C relay.

The only problem with the 2 fans is you would have to lose the shroud. The 16" should fit under the shroud with a little modification.

Sorry about the thread hijack Lunchbox.

Mike D,

I inquire about the engine elec. fans from an auto store that they don't have the 12" fans anymore, they have only 10", the brand was Sanden(Japan). But I passed by a used parts store and I found a 14" electric fan from a Volkswagen(Caravelle or the new Bettle). I tested it and WHOA! it's powerfull, the motor is about 4" long 3" in diameter w/ no housing or bracket, then I bought it for PhP600(about US$10).

All I have to do is test fit in the car for clearance,fabricate the bracket with aluminum, welding w/ TIG.

p.s. As Mike says, I too sorry for thread hijacking