Itinerant Air-Cooled

Have you been able to check that the distributor advances to 28 degrees at full advance with vacuum hose attached and disconnected? It’s straightforward to know for sure if you have a problem here. I would be surprised if a faulty vacuum can caused backfiring which is a significant symptom. If you need a new one then I personally would only consider a rebuilt one.

It runs it runs it runs! Ok, so it turned out to be (partially) the distributor. I swapped it out for a 009 (I know) that my friend loaned me. It ran much more better with no backfiring. Ok, great! But there was still some hesitation when you first accelerate and again at around 30 mph. After moving past that, it ran great again. I took it on the highway and it drove great at 60-ish mph.

I looked at the arm in the AFM and this is what I saw.
See how much wear is on the track? Pretty sure that's my problem. I swapped the whole AFM out for another unit that had a much better looking track. Test drove again with the 009 and the new AFM. It drove beautifully! What a relief, after all this time.

So with the SVDA distributor out, we decided to clean it up and lube it again. This caused the plate inside to move much more freely now, so I dropped it in and it also ran great. I could tell a bit of a difference in smoothness with the stock SVDA vs. the 009 for sure.

So that licked my issue and I'm really happy with how well it runs now. The Bosch FI is a beautiful system once it's all in good working order. Next I'll be doing some more test drives in it so I can be comfortable driving it on longer trips in the future.

russwiththebus wrote: ↑

Sun Nov 19, 2017 8:31 pm

try to put any kind of pedal down, it bogs down, starts back firing and losing power.
sounds like this is where my problem might be.

Nope. You can pull off the vacuum advance on a properly running engine with little discernable effect.
Colin

Does that sound like maybe the mechanical advance in the distributor was sticking instead? Anyways it's running smoothly now. Time to test drive it some more!

All bets are off until you read timing with a timing light. It is well worth taking the time to test that SVDA. 009 is just wrong. Needs to be replaced forthwith! Get it back in, static time to whatever yours should be out of the box (7.5 btc?) then after the engine is warm set maximum mechanical advance to 28 degrees. Make sure your idle is low enough to keep the advance weights in place. Rev a few times - and check idle timing again. You are looking to see a) whether you get mechanical advance, b) how much mechanical advance you get and then c) how sticky the advance plate is. Once you have that put the vacuum hoses back on and check / record timing at maximum vacuum advance. Once you have all that recorded, and assuming it's not advancing dangerously far in either instance, go for a drive and on your return check idle timing again.

Well the 009 was just for testing purposes, and it did confirm the distributor was giving me problems. It's timed correctly now, but I don't like how the timing drifts at idle. It should stay right on the mark, but it has a little bit of bounce in either direction. I'm gonna need a correct, working distributor before I can fully drive it.

The SVDA crapped out again, so (reluctantly) ordered the Pertronix Flame Thrower. Should be in this week.

russwiththebus wrote: ↑

Mon Nov 27, 2017 7:22 pm

The SVDA crapped out again, so (reluctantly) ordered the Pertronix Flame Thrower. Should be in this week.

Had an engine that grenaded on me about 7 years ago .... sold it for $100 with the stock dizzy on it...still kick myself for it...

russwiththebus wrote: ↑

Mon Nov 27, 2017 7:22 pm

The SVDA crapped out again, so (reluctantly) ordered the Pertronix Flame Thrower. Should be in this week.

It is a shame and it's worth having it rebuilt when time and money permit.

Well it's not mine to rebuild anyways. The Flame Thrower is in now and unfortunately did not run well with my Bosch blue coil. It had less than 3 ohms of resistance when tested, so we found a random old coil that did and threw it on. Fired right up! It's timed now and running so great now. I'll probably order a new coil at some point (the Pertronix 40511 seems compatible) but I'm very happy with it now. I know it would be nice to have a rebuilt Bosch dizzy, but honestly I see nothing wrong with the Flame Thrower in there! The timing is dead on instead of being all wavy, it doesn't miss, and the advance is correct.

So everything has been running great engine-wise, but this week I suddenly couldn't get it in reverse! After inspecting underneath, it turns out I'm missing the front shift bushing as well as one of the bushings out of the rear shift coupling. Found a couple of spares and threw those on, it instantly brought back reverse and just made everything shift much better in general. I'll definitely be ordering new bushings soon.

Got a new Pertronix coil installed, too.

russwiththebus wrote: ↑

Wed Dec 06, 2017 10:05 pm

So everything has been running great engine-wise, but this week I suddenly couldn't get it in reverse! After inspecting underneath, it turns out I'm missing the front shift bushing as well as one of the bushings out of the rear shift coupling. Found a couple of spares and threw those on, it instantly brought back reverse and just made everything shift much better in general. I'll definitely be ordering new bushings soon.

These are the best fixes :)

russwiththebus wrote: ↑

Thu Dec 07, 2017 11:21 am

Got a new Pertronix coil installed, too.

When you get a chance see if you can borrow a good, correct SVDA. Would be interesting to feel the difference. I'm collecting them!

I'll try it if I can borrow one, but I am honestly pretty happy with the ignition setup the way it is. I can't image it getting much better!