Hi All/Naachi

I do have a Brooklands manual as well as the repair CDs from MBUSA - and now you guys! : )

Fuel pump - was dripping oil from the vent hole for months and I couldn't figure out where the oil came from - as you said, the oil was all over the place but the clue was it came from only the right side. Finally I used an inspection mirror and and kept poking around under there when I spotted the vent hole. The spacer was OK. Put a rag under the vent hole and no more drips. Anyway the pump didn't cost too much at USD33. The new Pierburg pump design has a valve inside to prevent fuel overflow between the carb and tank when the car is sitting. I thought that with the vacuum fuel recirulating circuit, the pressure can't get too high?

Choke pull down - this one stumped me. Mine is the one with the air sensor under the air filter housing and vacuum solenoid under the headlight. From what I read, its is supposed to work under 20 Celcius so mine is never activated. Anyway, I run full vacuum to it now on the original vacuum circuit. I didn't want to remove the choke as I wanted it all original and the carb is definitely the right carb too with the metal tag and all.

Idle stop screw - mine was definitely moved. I reset it by using a feeler gauge to opened just a crack and the idle set by the air bleed screw like you mentioned. I think this is close but would like the factory procedure if you have it.

Timing - I cannot get this car to ping no matter how advanced the timing is. Not sure why but it could have been the over rich mixture. As it is now, any more advance and I loose my smooth idle. In trying all combinations of timing, there is hardly any change in mileage.

Float level - As mentioned, this is making the biggest change. I did make myself the measuring tool. Needle valve is new. The manual called for measurement at the highest point of the float but I measured at the lowest/tapered end, reason being, for a 8mm drop at the low end, there was hardly any change at the high end as it pivots around there. Also the low end is providing most of the leverage work. I did this in 2 stages - first drop was about 3 mm, some good change in pickup. Second drop another 3-4mm even smoother but not as powerful pickup as the first stage above 4K rpms. I'm OK with that so currently at estimated 7-8 mm drop. With all that practice I can now get the carb out in under 10 minutes.

Anyway, still monitoring the fuel gauge with this change and will post back on my findings. A good weekend to all!

Oreo

Hello,
You need to look at this webpage for all the info you could ever need for a Stromberg 175CDT/U:www.ruddies.business.t-online.de/se175cdtu.htm.
Have a good weekend.

__________________
Nachi11744

Tomguy
How do youy do that?
cK

Just quick conversion for you guys (gotta love TI graphing calcs! )

cK: Hit 2nd, and then 5 (conv) on a Ti-85 to do it...

Attached Thumbnails

 

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Current:
2021 Charger Scat Pack Widebody "Sinabee"
2018 Durango R/T

Previous:
1972 280SE 4.5
2014 Jeep Grand Cherokee Limited "Hefe", 1992 Jeep Cherokee Laredo "Jeepy", 2006 Charger R/T "Hemi"
1999 Chrysler 300M - RIP @ 221k

Naachi

Wow! Fantastic website! Just what I have been looking for. All my questions are answered! None of my books go into the carbs in this detail. Thanks!

Oreo

Hello,
Here is my W115 200s' fuel consumption for the last three full tanks of gasoline: 11.3l/100km, about 25miles/imperial gallon or 21miles/US gallon. Before this it was 13l/100km, 21m/impg,18m/usg.
The reason I am posting this is because I had to have a broken intake/exhaust manifold securing stud repaired and after the repair and proper reseal of the intake, the fuel consumption has improved without any adjustments, so even a slight air leak was causing a dip in fuel *economy*. I cannot stress the need to rule out ALL other factors for poor fuel consumption before messing around with any type of carburation.
Have a good week.

__________________
Nachi11744

Naachi

Thanks for the new tip - that is excellent mileage. I will try and do a check for leaks.

BTW what kind of tire size are you running? Just a thought - I'm running 195/65 15s. Will my my odometer calibration be off?

Oreo

Hi All

I just wanted to report back that I have achieved some success in lower my fuel consumption. My mileage is now within the 14-15 l/100km mark when it used to be 17l/100km. Since the factory spec was 14 in urban cycle I'm within the ballpark, taking into account my very severe urban cycle of over 90 percent bumper to bumper.

Just to share with all the changes that helped:
1) Lowering of the carb fuel level - some data showed float height at 16mm and some showed 19mm. Overall I lowered about fuel level 7-8mm using the 19mm float height. This help smooth out the engine a lot. Engine became very smooth at all rpms. My mixture must be closer to stoichometric.
2) Changing the damper oil back to ATF from 20W-50.

Step 1) did not result in a lot of immediate fuel savings as I was in severe urban cycle (1 and 2 gear). but I'm sure my first highway run will be excellent as you can feel the engine smoothed out from the mixture change. No 2) helped a lot as my start/stop conditions was very heavy on the damper fuel enrichment (= accelerator pump). In hindsight I feel that the car accelerates smoother and faster now where the 20W-50 bucked the car a little - which I misconstrued to be more power!

Thanks to all who help me think this thru - Peter, Mark and especially Nachi!

Regards
Oreo

Hello,
The 14-15l/100km is about the best you will achieve in the tropics with a/c going all the time in traffic jams.

The float level measurement can be confusing, but I have it all figured out.

1. Solid needle valve(no ball)in early 175CDS or CDT(W115):15-17mm

2. Ball needle valve in later 175CDT and CDTU(W115):16-17mm with ball pressed in

3. Ball needle valve in 175CDTU for M115(W123&W460):18mm+-0.5mm without pressing in ball(carb body set at 20degree angle)

4. Ball needle valve in 175CDT for M102(W123&W201):19mm+-0.5mm without pressing in ball(carb body set at 20 degree angle)

OK, confused yet? This is the reason I do not like to give out specs, rather let someone find it and figure it out for themselves.

I run engine oil SAE 30 in the damper and am satisfied with the acceleration as I rarely use full throttle, having the habit of stepping off relatively slowly and just rolling along to higher speeds. At high revs(4000rpm+) acceleration there is some smoke, but I cannot ascertain if it is black smoke due to overichness or just the downturned tailpipe blowing all the dust particles off the road surface.
Have a good week

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Nachi11744