Centrifugal 009 vs Vacuum 035

[Royal]

I have recently spent a few more than a few hours trying to get that perfect tune in my 1500sp.  I originally had the 009 distributor which as you probably know has centrifugal advance only.  Adjusted the valves, set the points, timing dead on per the instructions.  Took MiGi for a ride.  Everything seemed pretty good. 

Came home pulled the 009 and put in an old 035 vacuum only (SVA) distributor that I had prettied up with cleaning and lubrication.  New points, rotor, cap, condenser.  Couldn’t get the idle speed down without mucho tweaking.  Very time consuming getting the “bypass screw” “volume control screws” and the timing advance just right.  (I have the single H30/31 PIC carb).  BUT when it is adjusted properly, it runs a lot better than the 009.  The 035 is “load sensing” wrt advance and there is no flat spot.  The 009 is RPM sensing only WRT advance.  Maybe VW engineers knew something eh?  The complete 009 is going to go in my spare parts kit.  Ready to “plug in” if needed. 

[edward ericson]

Roy, what, exactly, did you do to get your idle right? Mine’s been high (1300rpm or so, at best) since I bought it, and I’m fixing to tackle it this season.

And what’s your static and 2500 RPM timing now?

[Royal]

Ed, With the 009 my idle was running about 1200 which didn’t really bother me since it is a centrifugal distributor.  But with the 035, the vacuum advance starts to pull in at about 1200 rpm with a normal engine.  So, I followed this as close to the letter as I could:  http://www.vw-resource.com/tune-up.html#problem

It turns out that even with my “bypass screw” seated, I still was idling at about 1200rpm.  Followed the procedure at the end of section #7 until I got tired.  Every time I went through the tweaking procedure, it got a little better.  Now my idle is down to 950 and I may just leave it.  – at least for a while (my back hurts).  Timing is set (035) at 7.5deg BTDC at idle with no vac advance.  With vac advance hooked up it is about 15deg BTDC at 1000rpm and about 35deg BTDC at 3000rpm.  Now my bypass screw is actually working and it does something.  It is a slow process getting everything right.  But, it’s worth it.  I’m not quite finished but am done for now, – Runs like a scared rabbit.  I’m interested to see if it runs cooler/hotter but have to wait for the weather to warm up a bit first.  Also the mileage- ?.  We’ll see.

[edward ericson]

Dude, that is very cool. Pretty sure I have the same problem–bypass screw is seated. Like I said, it came to me that way, is running nice otherwise (though def. rich), and so I’ve been OK leaving well enough alone.

But getting like 24 mpg & think I should be closer to 30.

look forward to getting this right in the spring.

Thanks for showing the way.

[Author]

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