009 narrow advance?

[BumbleBus]

Hi. So I've been diagnosing a random power failure situation all summer. I've got Bumblebus running well at this point having gone through a laundry list of things to fix/replace etc., but now I have one final question(s) before I attempt camping again this weekend.

I got an aluminum timing scale today! Finally. I've been "timing" based on old marks, guesses etc. all summer. Once I got the scale on and re-adjusted all valves to TDC I realized that I've probably been running about 8-10 degrees too advanced for the last 300 miles. This would likely explain my high engine temps yes ( viewtopic.php?f=3&t=10970#p193466 )??

Anyway... I got my strobe on there and got the max advance to 28-30* BTDC (it "wobbles" slightly back and forth). The engine sounds better than I've ever heard it to date... but...

...at idle it's only settling back to around 14* BTDC... not the 7-10* I was expecting. Should I chalk this up to a crappy narrow advance 009 and call it good for now until I can go PDSIT/SVDA someday or is there something else I should be looking at. Idles happily at 950ish RPM once I adjusted for best lean idle and tweaked the carb throttle stop.

THANKs for any tips!! I feel like I'm learning a LOT, but am also second guessing myself a ton.

[hambone]

From my limited understanding, idle timing is irrelevant with an 009. It's all about full advance.

[BumbleBus]

Thanks hambone. That's what I'd read, but I'd never read about such a narrow advance. Just got back from a multi-mile test drive and it ran well if a tiny bit gutless feeling and then... mehhhh... died on me mid-road [back road]. WTH!? All my efforts and the random power failure continues...

...BUT... the one, absolute, single thing I haven't done yet is to remove/replace the tank sock filter. There is clean gas in my little plastic filter, but that might not matter under load etc. To test my theory I vigorously shook Bumble back and forth and VROOOM... started up. Drove another mile and... fehhhh... dies again. Wait a minute, shake, start, drive a couple more miles and finally make it home.

Tomorrow... I drain the gas and remove the sock filter. If that solves it we're camping! If not... we're tent camping. Bah.

[drober23]

Bumble,

Are you sure the 009 is lubricated well enough to give you its full mechanical advance? If it is crusty inside, it may not be advancing all the way, or perhaps not be returning all the way to rest at idle.

If the 009 is in good condition, I would expect it to come further down than to 14°. But, as people say, you don't drive around at idle all day. So it is much more important to have it correct at driving rpms than at idle. I would keep an eye on it, and check it every now and again until you are certain the 28 at full and 14 and idle is consistent.

The SVDA uses vacuum to INCREASE the advance when NOT at full throttle. This allows the engine to have a little extra oomph when not under full load, but still operate safely when it is working its hardest.

[BumbleBus]

Thanks for the reply drober23! That makes good sense especially because I've been camping in such dusty places this summer.



I didn't know until yesterday about how the mechanical advance weights worked, but watched the old VW service timing videos about it. I diligently make sure the dizzy rotor lobe has a couple drops of oil, but never knew to clean the rest of the dizzy.

Friday Sept 14th:

1) Remove tank sock filter and rotary filter... both very likely clogged. Put in new "Isreali" filter.

2) Remove dizzy. Clean. Re-install. Re-time. Hope for <14* idle.

[BumbleBus]

1) Remove tank sock filter and rotary filter... both very likely clogged. Put in new "Isreali" filter.

So here I am removing the fuel lines/filters, draining gas etc. etc. and gas is absolutely just free flowing out of the tank outlet hole so I highly doubt the sock filter is the culprit... let alone even still there. Hmmm. I siphoned as much as possible, but there was still 2+ gallons that came out the bottom. Nasty stuff. Hoping for an all electric world soon. Also hoping that the CB Perf rotary metal filter is the culprit at this point... otherwise, what... cracked head or something equally horrible? I've ruled out ignition switch, coil, points, too tight valves, compression, vacuum leaks, fuel flow, cleaned all grounds etc. etc. What else could random power failures be?? Carb? Hmm. Just cleaned the snot out of it the other day. Maybe I should have taken it all the way apart and checked the float valve or something. Anyway... sorry... just talking out loud... hmmm...

Diagnosing bus issues always makes me want to drink. A lot.

[johnl]

Bumblebus, On my 009 I had to take the plate that the points set on out to be able too bend the little stop that the advance weight hits. I had to bend it in (towards the center of the distributor) to limit the amount of advance. My bus ('72 tintop,1700 w/kadrons and a header) loves 12*@idle and 28*full. I have heard that the advance curve on the 009s can be inconsistent from one distributor to the next. It may be that you have to bend the stop on yours out to get a couple more degrees. IIRC the plate that the points set on will go back in two ways but will only "work" one way so if you try my idea pay attention to how it comes out. Good luck,John

[Amskeptic]

Bumblebus, On my 009 I had to take the plate that the points set on out to be able too bend the little stop that the advance weight hits. I had to bend it in (towards the center of the distributor) to limit the amount of advance. My bus ('72 tintop,1700 w/kadrons and a header) loves 12*@idle and 28*full. I have heard that the advance curve on the 009s can be inconsistent from one distributor to the next. It may be that you have to bend the stop on yours out to get a couple more degrees. IIRC the plate that the points set on will go back in two ways but will only "work" one way so if you try my idea pay attention to how it comes out. Good luck,John

I hope he replies. I've been waiting here for months for an update.

Was 12/28 your goal? What was it originally?
Colin

[johnl]

Yes on the 12/28. When I first set the total at 28* it idled at 7 or 8*.