Patricia A. Mayer's 3.0 CS / Paul Cain's Fjord project / The 300 mile Test Drive / VIII / Final Punch List

[paul cain]

Not a silly question. Good question. Yes, it was coiled in an 18'' diameter loop. I put a drill bit in one end and and clamped it in the vice. Then straightened. Lots of micro bending was required in the vice with a cloth to protect the finish. It took about a half hour to get it all straight.

 

[grnder95]

Hello Paul,
Do all M30B30 carbureted engines have a return fuel line? The reason is that my 1973 3.0cs Belgium import has a single fuel line.
BTW, this is a great find, congratulations,
Regards Victor

 

[HB Chris]

Return line was introduced on the facelift 1974 model year coupes, as well as 74 2002s.

 

[JFENG]

Not a silly question. Good question. Yes, it was coiled in an 18'' diameter look. I put a drill bit in one and and clamped it in the vice. Then straightened. Lots of micro bending was required in the vice with a cloth to protect the finish. It took about a half hour to get it all straight.

The make tubing straightening devices that take just a few minutes to use.

 

[paul cain]

Victor, @grnder95 re: o all M30B30 carbureted engines have a return fuel line? Many layers to this answer:​

I cannot speak for Euro market changes, however 9/73 is what they call in the industry a 'minor facelift' and insiders (suppliers) know it to be the serious phase of cost reduction. There are many, many examples of this on E9s, along with many design feature changes. The car had been in production for almost 5 years and it was due.

Starting in 1973 the U.S. tailpipe emissions where really coming under scrutiny and all manufacturers and BMW and others were really scrambling to meet the requirements. If you look through the Zenith carburetor history, there were a lot of changes in 1973 & 74. Fuel recirculation was one of those features and my car is a very early build (VIN No. 4335055), the 55th US market '74. So, it was fitted with a return fuel line and all the fittings to the carbs. Interesting, the carb's did have the fuel barbs for the return line and it was all plumbed, but the casting were not drilled and there was never any fuel returning through these lines. I am speculating that the USA market '74 carbs were not yet available. This was an interesting discovery during the carb rebuilding process.

BTW, I am having a blast discovering many very original features on this example.

 

[rsporsche]

Out of curiosity, how was the fuel returned to the tank? (i get that it was a metal gas line that would have run under the car) it couldn't be gravity as the gas line went back under the car. was it a vacuum from the fuel pump that drew the fuel back to a sealed tank?

 

[JFENG]

the carb's did have the fuel barbs for the return line and it was all plumbed, but the casting were not drilled and there was never any fuel returning through these lines.

Maybe a version of VW diesel scandal from a few years ago?

 

[coupedegrace]

Maybe a version of VW diesel scandal from a few years ago?

Except that the diesel scandals were based on OBD lying to the test equipment. If VW had just stuck a tank filled with urea in the car and run dummy pipes to the exhaust, that would be analogous. I would be surprised to learn that EPA's emissions tests consisted of just looking at the car and not actually testing tail pipe emissions. If they did conduct tail pipe testing, these non-functioning return lines wouldn't have improved the numbers at all. Of course the E9 sales numbers were so small, relatively speaking, that it could have been a gamble based on their being relatively small fish and thus being tested much later.

Anyway, hard to draw broad conclusions based on a sample of one. @paul cain - does it seem like your example could be a defect? As in all they needed to do was drill holes in the casting for the returns to work, and this was somehow missed? I can envision a scenario where, if possible, Zenith or BMW were trying to use up some old stock by modifying it to work with return lines. In this scenario your example, or perhaps a whole batch of old castings, just missed this step.

Playing "what if" is fun. In any case, to John F's point, whatever the case may be it was all the engineers faults!

 

[paul cain]

@rsporsche Fuel returns to the tank from the residual fuel pump pressure.

@coupedegrace I agree completely with your comment: ''these non-functioning return lines wouldn't have improved the (emissions) numbers at all.'' Also agree it was a modest gamble to ship without the fully compliant return line. This was early, early days of of C.A.R.B and EPA compliance, as this was the first wave of serious tightening of tailpipe emissions. One can imagine the 'enforcement' department must have been tiny by todays standards. VW's immense arrogance will change that world forever.

 

[JMinPDX]

Starting in 1973 the U.S. tailpipe emissions where really coming under scrutiny and all manufacturers and BMW and others were really scrambling to meet the requirements. If you look through the Zenith carburetor history, there were a lot of changes in 1973 & 74. Fuel recirculation was one of those features and my car is a very early build (VIN No. 4335055), the 55th US market '74. So, it was fitted with a return fuel line and all the fittings to the carbs. Interesting, the carb's did have the fuel barbs for the return line and it was all plumbed, but the casting were not drilled and there was never any fuel returning through these lines. I am speculating that the USA market '74 carbs were not yet available. This was an interesting discovery during the carb rebuilding process.

BTW, I am having a blast discovering many very original features on this example.

Even more so in California than the other states. I recall living in CA in the late 1980’s & 90’s when my 2002 not only had to pass tailpipe inspection but also under hood “visual” inspection to ensure all smog equipment was intact. I realize Mrs. Mayer’s e9 was not in CA but is it possible it would have failed visual inspection for unconnected return lines back in the old days? Did 74 coupes come in “CA” versions and “48 state versions”? Pretty sure 75 & 76 2002s did.

 

[HB Chris]

No CA version of the e9. Visual inspection would not find a fuel line, they wanted to see smog pumps, egr, etc. The 2002 had a CA version in 75 and 76 though.

 

[paul cain]

It's U.S. to European conversion day at the shop:
One and Four: Measure three times, scribe once. No caffeine for the prior four hours. Drills, disc grinders and finishing work with my favorite Dremel tips.

Three: thank you to @Mike Pelly for the gracious gift of the full Euro fog lamp assembly.

Early rear tail lamp center panel in solid brass. This finishes out so much nicer in full chrome. I am jettisoning the original stamped aluminum panel that had the U.S. market license plate lamps.

Seven: Custom license plate mounting bracket is made out of 16 Ga mild steel and has welded standoffs and 6mm all thread inserted in the standoff. The all thread studs pass through the center panel's three mounting holes that are already in the body.

Nine: Facia end is plug welded to fuse all three of these pieces together.

Seven shows: opposite end of the standoff is 14mm tooling washers welded to the standoff. This is the ideal mounting interface to the above center panel as this frame is now very secure in its position. This will go out for gold zinc plating in the next batch.

Ten: European license plate frame appears to be floating off the rear tail panel. This is an aftermarket part from the Mercedes Benz world that is very nice generic piece in stainless steel. It will be fully polished on the perimeter and mounted on the backing plate with four 3mm machine screws.

 

[HB Chris]

Paul, How will you mount the CA plate?

 

[adawil2002]

Euro to US plate for the rear, make 2 T shaped brackets.

 

[paul cain]

@HB Chris re: How will you mount the CA plate?

California plates? California plates? I don't need no stinkin' California plates!

 

[HB Chris]

Ha! You already have the blue plates, you can’t fool me.

 

[coupedegrace]

Euro to US plate for the rear, make 2 T shaped brackets.

Clever use of hex-key fasteners - something that's probably not in every casual thief's toolkit.

 

[paul cain]

One: filler panels are now fabricated and welded in, to cover the US Federalized bumper shock large holes.
Two: Exceedingly difficult fitting of the bumper bracket boot to the body. This is test fit no. 18 controlling the width and height. I destroyed these boots in the process. The temptation to be avoided is making the slot too wide. Then the boots will never stay in position.
Three: Close up of boot full fitted. E9'ers will see the error I created in this photo. Also visible in no. four. Woops.
Four: Bumper bracket is fully fastened to the frame rail, this is key as it controls the side to side positioning. This vertical positioning has to be nailed before you bring the bumper assy in for the first test fit
Five: second dry fit of the full bumper assy including controlling the bumperette positioning. Note the bumper strip piece controlling the bumperette position.
Six: Full view of all of the hardware in position. This is the second to final fit, AKA, everything is finger tight fitting. Alignments from all angles (including bottoms up gap to the body) look correct and even.
Almost ready to send off to plating.

 

[adawil2002]

Front repair & bumper looks correct & excellent.

 

[eriknetherlands]

Hi Paul; Fitment looks really nice.
Why do you have three holes (about 6 mm) around the bumper openings? My car (May '73 EU model) doesn't have those holes. Are they residual from the US bumpers? if so, should you weld them up as well?