Finishing Samson the M120 R107 - Page 6 - PeachParts Mercedes-Benz Forum

Roncallo · #76 05-14-2020, 08:57 PM

So it appears that I have no leak in my refrigeration system. What I did have was two fans acting as pull fans from the front and back. Basically making it like no fans at all. Apparently the R129 is wired backwards form the R107. Consequently I had the Auxiliary fan turning backwards and cancelling out the effects of the radiator fan. That makes the high side pressure shoot way up above 400PSI and the low side way up as well. And with low side pressures up at around 70PSI that actually becomes a heater. According to the manual today was ~25°C (77°F) when I tested, I should be seeing over 13.5°C (55.4°F) duct temperature. I was getting about 14°C (57°F) duct temperature. This could be just the effect of the R134 or maybe the condenser I put in sucks or possibly both. I am now well aware of one this the performance is better with lots of fans going. In any case, I believe its performing correctly, but as ****ty as any 107 on R134.

So vwnate Im envious that you were getting 50°F on a 100° day.

Roncallo · #77 05-14-2020, 08:58 PM

Quote:

Originally Posted by vwnate1

I love seeing problems solved by thinking ~ that hole saw using the filler neck is very good .

? So, what's capping the open washer bottle now ? .

A grommet will go in there with a filler tube to inside the engine compartment.

Roncallo · #78 05-15-2020, 11:29 AM

So last night I went out when the temperature cooled down to 70°F just like it was a week ago when I got 42° duct temp. This time I could only get 49-50°. So I am now hunting gown that 8°.

vwnate1 · #79 05-15-2020, 12:32 PM

Well ;

So many tell me they get low 40's out the vents, 50* is all I can get and the car's O.K. inside but it gets HOT out here, lots of window glass to let in the UV rays & heat...

I'm always flummoxed by adding two fans, one will do if it's properly done and no, puler fans don't work any better, 7th grade science class tells us that .

When doing basic cooling system and AC checks, always use a simple sheet of thin paper, the fan should easily be able to hold it in place at idle .

No air flow means all the other works done are not able to do their job .

My self, I always wire up the E-Fan via a relay to come on even with the engine shut off this aids in cool down and preventing engine heat soak .

Roncallo · #80 05-16-2020, 02:23 AM

Nothing is simple with this car. Couldn't find a suitable place where I could mount a fan controller. I could have put it straight up but it would have blocked off the cold air intakes. So I spent all day making up a bracket that would hold it in place. Had to prop it up at an angle to let the hood close properly. Tomorrow I will fit the assembly in place and paint and really start the install.

Roncallo · #81 05-16-2020, 02:43 AM

Quote:

Originally Posted by vwnate1

Well ;

So many tell me they get low 40's out the vents, 50* is all I can get and the car's O.K. inside but it gets HOT out here, lots of window glass to let in the UV rays & heat...

I'm always flummoxed by adding two fans, one will do if it's properly done and no, puler fans don't work any better, 7th grade science class tells us that .

When doing basic cooling system and AC checks, always use a simple sheet of thin paper, the fan should easily be able to hold it in place at idle .

No air flow means all the other works done are not able to do their job .

My self, I always wire up the E-Fan via a relay to come on even with the engine shut off this aids in cool down and preventing engine heat soak .

I attached the service temps and pressure charts for the 107. It is pretty anemic. I'm sure the 123's are similar.

Condenser and fan is a big this. Since I have only an electric fan on a relay that only runs when the temp gets hot, I am now connecting a radiator fan controller that will turn the fan on low speed when the AC is on. That will allow my radiator fan to better simulate having mechanical at idle.

It is not impossible to get 40's in an old MB, but it is impossible for a stock 80's MB to get 40's when the temps are north of 90° F. They wouldn't do it when they were new running on R12 and they certainly wouldn't do it 30
+ years latter without modification.

Also the performance test is done with specific conditions. Engine a 2000 RPM, windows open hood closed, blower on high and taking readings at the end of a 10 min period.

That test gives you the performance of the system. But putting the blower to the low position will also drop the temperature.

The other reason people might be telling you they get 40's is that they are just plane lying.

Keep in mind the performance table I attached shown maximums. Basically they are the numbers MB would have to see to accept a warranty claim. In reality the system should do better.

vwnate1 · #82 05-17-2020, 11:35 AM

Thanx for the graph .

I find they system is O.K., not fantastic, I have personally been in W123 Sedans in 100* F out side temps that were chilly inside, in city stop & go traffic no less .

I've seen the temperature gauge on others cars at 42* F when I asked if they were sure they were actually getting that cold because I so rarely get below 60* F outlet temps.....

Yes, I know it's not uncommon for some to embellish / lie....

I'm old and I remember in the 1960's the trick to getting really cold AC was to scavenge a big condenser from a scrapped Cadillac , nothing has changed - the same with cooling system : you put in the absolutely biggest & thickest (minimum three rows) radiator and let the thermostat do all the work....

I know the 107 chassis is tight, my '75 W107 350SLC V8 was snug, I didn't do any Hot Rodding apart from driving the crap out of it, you're doing a great job here, too bad not many are following this as it's not only interesting it is highly educational .

I know there's specific differences between the pressure / working load of R12 Vs. R134a ~ the other day I was driving my W124 sedan with SANDEN 7 series compressor and large parallel condenser in the 70's out side temps and the outlets still only dropped to 50* .

My Delco Aire service training was so long ago it pre dated R13a and I remember them telling us to not do what the lazy guys did : slowly charge the system until you got to 45* F at the dash board vents, I understand that R13a works best at lower system pressure so I wonder of maybe I should try that but it's working so I'm loathe to foll with it now .

Roncallo · #83 05-21-2020, 02:00 AM

Well I'm officially in AC tuning hell now I got the fans installed and working perfectly and still suddenly have lost all the performance I had when I first charged the system. Left a post on Tech help. I'm currently thinking monovalve problem. Lets see what the experts have to say.

vwnate1 · #84 05-21-2020, 10:30 AM

That's kinda vague.....

Do you mean it's not as cold as it was initially ? .

Please post a link to the other thread....

Roncallo · #85 05-21-2020, 07:04 PM

Quote:

Originally Posted by vwnate1

That's kinda vague.....

Do you mean it's not as cold as it was initially ? .

Please post a link to the other thread....

That's correct, I lost about 8° - 10° somewhere along the line. See my thread in Tech help. " Sudden loss of AC Monovalve". My brother is loaning me his recovery system that I can play with for a while. Hes shipping it from NY so I don't expect to see it until the end of next week.

In any case my grommet for the WW tank arrived with some 1.5" Al tube. I made a quick mock out of a 90° tube that I will be playing with mounting and plumbing solutions for the next week.

Don't worry about the welding.

When I have it all mocked up I will send it to a real welder.

Roncallo · #86 05-30-2020, 10:13 PM

Got some motivation to work on the windshield washer today. I got the mount made for the 4qt washer bottle and it fits in, inside fender installs without interference, dosen't hang out the bottom except. Making the penetration through the inside fender will put the tube right through the main wire harness. I could move the harness but I decided to down size the bottle to 3 qt. It just clears a bunch of problems. Also this is not a winter time daily driver like my Taurus or F150 that I go through 2 gallons every winter. I was also looking at the old GM glass bottles that were used between 1959 and 1968, They held 16 oz. Ford and the MB R113 had a plastic bag. I think I'm good with three qt's. Now the only problem is they are out of stock of the 3 qt ones. I might even consider a 2 qt. Those are in stock.

Roncallo · #87 06-01-2020, 06:59 PM

So now I'm at a total stand still. Second refrigerant recovery tank I ordered has not shipped yet. The new 3 qt windshield washer tank is on back order until late July. In any case I cut the bottom off my 4 qt tank to bring the size of the tank equal to a 3qt tank. With that I can complete the mounting brackets and the rest of the installation hardware. I got the mounting and routing of everything all figured out.

The reservoir was fit into my test vehicle (Ebola) and moved around in different positions until a result that worked was found. Note the target practice holes drilled on Ebola to find the best installation location. The circled holes are the one I will actually be using. Once a successful solution was available and tested on the real car (Samson), a drill guide was fabricated so that hole locations could be transferred back to another 107. The drill guide was made by bolting pieces of sheet metal to preexisting holes in the 107 chassis. Since the new mounting holes were already established in the vehicle, new matched drilled holes needed to be drilled into the guide sheet metal that matched up with the existing holes already drilled into the chassis. This is done with the tools shown in the third and fourth pictures. I don't know what they are called but they are used in the aircraft industry to replace panels on aircraft that have preexisting holes underneath.

I needed to do this on both Ebola and Samson because without fenders on Ebola the final fit checks could not be established. With the reservoir mounting established, everything else can now be demonstrated on Ebola. With the final mounting position established on Ebola, I was now able to locate a suitable pass through position and hole saw it out and install a chaffing strip as shown in the 5th picture.

Roncallo · #88 06-01-2020, 07:04 PM

Final mock up of the tube is shown in picture #1 and 2. The part sticking into the engine compartment will be turned up and welded to a cap shown in picture #3.

Note that this is a mock up filler tube. The actual filler tube will be fabricated from a 60° mandrel bend for the bend turning into the engine compartment and a 90° mandrel bend to turn the tube up once it penetrates the engine compartment. Those bends are on order and I will be able to complete those prior to the replacement 3qt reservoir showing up.

I will also be getting a professional welder to do all the real welding.

Roncallo · #89 06-06-2020, 08:16 PM

Took a good 90 mile trip to test out Samson's AC today. Drive was uneventful both ways but results were 107 dismal. Meaning the AC performed just like a stock 560SL AC system (next to useless). OAT temp was 92°F Duct temps was running 62° F with windows open, ~ 58°F with Windows closed. Duct temp would go down to 48°F with windows closed blower on auto and re-circulation on. But no matter what I did cabin temp could only be brought down to 76°F. Believe it or not that is all withing spec for a 107.

The other thing I needed to check was does the car over heat. It ran significantly hotter as expected, Got up to 100°C on the highway ~ 105°C when I got off the highway and was stopped in line for gas. Hard to tell on a short trip like this but gas mileage came out to 21 MPG.

I will drive it around for a few weeks to verify there are no issues, then I will complete the reassembly of the interior. I'm still considering replacing the URO expansion valve with a German one I found in the UK. I still need to open the system one more time to correct some tubes so it will be a good time to change the expansion valve.

In the mean time the mandrel bends are due in for my windshield washer on Monday. I wish I could complete that next week but the reservoir is on back order until late July.

Roncallo · #90 06-23-2020, 04:07 PM

Got the welding finished on my windshield washer tube. Now its time to transfer all this to the real car. But I just realized that all the windshield washer plumbing is not present. I will need to go an archaeological dig through all my wiring and pluming from several cars to find it. Otherwise it will be junk yard time.

The 3 qt bottles are now in stock and I ordered one today.

Next step is scary. I need to drill the big 1.5" hole through my inner fender on the real car.