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All the complicated vacuum control on the distributor equipped in '71 VW Super Beetle were killed and the result was incredibly excellent. Combustion firing timing at idle speed was set at BTDC 5 degree as a matter of fact. BTDC 5 degree is the most favorable idle speed advanced position to attain comfortable accelerating at middle speed.

All the advancing effect were done without vacuum advancer, only by mechanical centrifugal advancing construction.

Once the information that no vacuum advancing device is required, diaphragm construction for advancing control should be eliminated also nipples for the signals on the carburetor are closed.

I just remembered that I got 009 distributor tens year ago! Now have I no reason not to appear stage if it has no diaphragm vacuum advancer. Some information tells that mechanical signal coupling delayed 90 degree, so hi-tension cord connection must be changed.

Anyway, smooth transition while acceleration phase is the first requirement, it' a interesting task for tomorrow. Super Beetle never betray to keep a geriatric enthusiast.

Vintage VW Training Film shows well how to keep Air-cooled Beetle even now---over 50 years old production. Especially complicated distributor control after 1971 that is completely different from those before inviting Muskie Act for anti-pollution.
As a common sense, combustion firing timing is set around BTDC 10 degree, but VW introduced ATDC 5 degree with dash-pod device to prevent quick rotation down at idle speed. The purpose of additional device is nothing but excessive amount of Hydro Carbon and Carbon Oxide in exhausted gas. It was extremely difficult to implement countermeasures applying conventional equipment and service engineers had very hard time to adopt with new Road Transport Vehicles Act.
Actually, double diaphragm vacuum advancer, ATDC 5 degree at idle and delayed returning speed with dash-pod looked so strange.
Thank to such a strange and queer additions I was so disappointed by spilled drive feel so I remember as a clear memory. Combustion firing timing suffer and dull response brought very bad drive feel without discussions. It was often the case that characters of motor response differ completely around 1970.
Consequently, my Super Beetle need to know the most suitable firing timing setting though the point is shown between 4~7 degree in the scheme, the discrepancy 3 degree causes much disparity without doubt. Repeating test run by myself is the residual way.
By throttle opening at 1500 rpm to 2000 rpm, seeking the most stable timing might be the way.
"Establishing Maximum Combustion Efficiency Firing Timing" is the Goal. Small space of 11AD engine room is nothing but a Garden of Blis for me! As I hate the word "Tolerance", want I null pin point. Am I a fool?

Deeper investigation about the combustion firing timing of '71 Super Beetle in the Website obliged me to try more experimental searches on my own vehicle. Deserting double diaphragm vacuum advancer, single diaphragm was invited---changing the original condition is a new condition. Complicated anti-pollution system was introduced in '71 models. This is why it makes is complicated and confused to set the adequate combustion timing. To know the best firing timing in every phase and smooth transition by driving by myself actually.

Old VW movie appeared in the Website illustrated centrifugal advance and vacuum one were drawn together but not shown actual advancing firing timing respectively in combination both advancing effect together. The width of the angle of BTDC drawn in the scheme is too broad to specify. Though some discretion might be required, both narration and scheme did not explain enough to understand the phenomena of combustion timing. I have been overcame by anxiety for long time about this problem. The fact that no improvement did not done by time passing, I tried to prove it by myself. Comparison of the centrifugal transient characteristics between 009 and ordinary distributor with no vacuum advancer should be known actually. This kind of unknown trial makes me enthusiastic.

New part ordered few years ago and left untouched 009 with fully mechanical centrifugal vacuum advancer, with no vacuum diaphragm device might be one of a choice. This kind of research and development is great fun for me and purpose to live. Coming long holidays in the beginning of May would be killed by this procedure.

Cataract surgery done on my right side eye is going favourably in about one month. After replacing from innate crystal tissue into artificial one has far improved my eyesight as to capable in driving vehicle.
Artifucial one has the focus poing at 5 m distance, so just a bit brule at infinity scienry but abalable.
Removing curtain from my right side eye as if covered with gauz , I feel great at all. To be more specific, the aspherical construction caused ring shaped blure and ghost in the hi-light, but they are acceptable for me. And the color is too better, white is so transparent, no complaint if different from innate lef side. God would give me some punishment if I declare something.
My quality of life has far improved, I appreciate my eye doctor and sophisticated technology in the field.

It's a great fun for my life to compensate the gap between overlooking and under looking. Basically, I gathered necessary information by consulting papers and articles written by former researchers in specific field. It was so difficult to do that wasting time. Articles I wanted were floating in the Ocean of them. But, now, in the period of Internet, Web is scattered in every direction and very easy to do that in very short period of time.

In spite of golden condition, I have been in misunderstanding thought about combustion firing timing of VW Super Beetle for over tens of years. I knew about the double diaphragm vacuum advancer specifically equipped in '71 production and the fact that advancing and delaying functions performed done at the same time. Recognizing such a function with watching the scheme actually, I still believed in the necessity of vacuum advancing effect for smooth acceleration. The shape of mechanical distributor was that of equipped diaphragm(single) chamber aside, so printed in my Cortex. This is why I fed vacuum signal to distributer without doubt for long time until few days ago. I had some suspicion on the function of accelerator fuel pomp in the carburetor body, because of ill function while departing phase.

Watching up the graphic drawn the relation between vacuum advance and delay also mechanical centrifugal advance, I come to the conclusion that vacuum advancing is not always necessary for replacing distributor from double diaphragm to single or less chamber distributor! After adjusting the timing at zero degree under no vacuum condition, I was so surprised to feel completely different attitude of 1600 cc AD motor as if released from heavy burdens. In addition to lubrication on the steering gear box, these improvements changed it's character like different vehicles. Also, first idle phase with stall tendency was far improved without thermostat function.