Upgraded ignition for air cooled VWs

Since I like this board better than the VW specific ones, I’m hoping to get a few good ideas here.  I have a Super Beetle that has a 1500 SP engine, still running a points distributor.  It tends to backfire a bit when letting off the throttle, and has done it with a new carb and with an older carb I rebuilt.  Timing has been checked multiple times.  I’m thinking it is time to upgrade to electronic ignition.  Anyone have good/bad experiences with any particular brands/models of ignition systems?  I think I’d rather replace the whole distributor instead of putting in a pertronix drop in, as I don’t know how good of shape the distributor is in. 

I don't really understand. Backfire as in out the exhaust? Technically up the intake has a different term that nobody uses, but are you talking about up the intake?  If it's out the exhaust it shouldn't be ignition related in any way. If it's back up the intake it COULD be the ignition if the ignition is either firing a cylinder while the intake valve isn't totally closed, or the spark impulse is jumping between two spark plug wires and firing a cylinder whose intake valve is still open. Those are the ways it COULD be related. Does the car have any other issues?

Actually going through this now with 2 coworkers beetles. 

If your problem is indeed ignition related I would place bets on the advance mechanism sticking.  A Pertronix drop in points replacement wouldn't help with that. Cleaning, lubing and replacing worn parts of the distributor is the fix.

Both guys here are going with the Pertronix Ignitor distributor for around $130. Being a new manufactured unit it shouldn't suffer with worn bushings and sticking flyweights.  I have no idea what the advance curve in it is though. One guy here is installing it in a stock 40hp motor and the other plans on dropping it into his 2200cc stroker motor.

My favorite drop in distributor is the 123 unit. Particularly the one with bluetooth so you can adjust the curve with your phone. Those are $500 though  But the quality is fantastic. 

The rockauto electronic ignition conversion kits are the pertronix units, IIRC.

In reply to Vigo :

Not 100% sure where it is coming from - but I’m guessing out the exhaust, so maybe backfire is not the right term.  It is very possible I just haven’t got the carb dialed in right, but at this point I’m willing to toss some money at the ignition system before I keep digging.  No other issues I can think of - it had been having trouble runnng at idle after its Lemons rally trip, but adjusting the points fixed that.

I have no faith in the overall condition of the current distributor, so it’s getting put on the shelf as a spare.

The compufire drop in is better quality than the pertronics, and all other brands are not good enough quality to purchase.  None of them.  Only buy actual Pertronics or compufire.

The compufire dual coil unit is even better, if you can afford it.

My Alfa has the Pertonix unit from VW.  Has worked great for 20 years now.

If its backfiring out of the exhaust, then it is due to a rich condition I think? No expert by ANY stretch, but have you checked plugs (does it look like it's running rich)? Have you tried jetting the carb with a smaller main jet? It could be the float settings I believe as well as the ball valve thingies that maybe are allowing additional fuel with the butterfly closed?

You adjust the valves recently and change plaugs/wires recently? 

Interested in the electronic ignition if it really is an easy button solution, but everything I have been reading is it can cause more trouble than the dizzy.

Plugs are usually brown when I check them.  One thing I forgot to mention is with the current carb, I can usually keep it from backfiring at all if I leave the throttle just a smidge open, instead of getting off the gas entirely.  I’m far from certain it has anything to do with the ignition, but I am also thinking I’d rather go with a modern ignition system first, and see if anything changes, then go back to fiddling with the carb.

That does not sound like (just) a timing issue. I just toss in a Bosch 009, adjust, and call it a day on aircooled vws.

Dad has a '74 VW Type II Camper

Couple years back we bought him a new distributor and a Petronix unit for his birthday.  He loves it, one of the best updates he did for it.

I have a Class 11 Bug, it had run a Petronix in several Baja races prior to me. I ran it and the first time gave the car a pretty good beating, knocked off the exhaust on a rock. Kept running I'm a believer in Petronix. 

It is amazing what a brand new distributor will do for an old VW engine.  This is stolen from some nameless place on the internet.

Deceleration backfire is caused by fuel burning in the exhaust manifold or header. Something you should understand before going any further is that a motor in perfect tune will exhibit deceleration backfiring.

I am not sure I agree with the last line, but it is from the internet so it must be true.  The question here is will better ignition burn more of the fuel in the combustion chamber leaving less to "pop" in the exhaust ?  

I will leave this here.  Because race car.  

eastsideTim said:

Plugs are usually brown when I check them.  One thing I forgot to mention is with the current carb, I can usually keep it from backfiring at all if I leave the throttle just a smidge open, instead of getting off the gas entirely.  I’m far from certain it has anything to do with the ignition, but I am also thinking I’d rather go with a modern ignition system first, and see if anything changes, then go back to fiddling with the carb.

What carb(s) and have they been tuned at all?

L5wolvesf said:

eastsideTim said:

Plugs are usually brown when I check them.  One thing I forgot to mention is with the current carb, I can usually keep it from backfiring at all if I leave the throttle just a smidge open, instead of getting off the gas entirely.  I’m far from certain it has anything to do with the ignition, but I am also thinking I’d rather go with a modern ignition system first, and see if anything changes, then go back to fiddling with the carb.

What carb(s) and have they been tuned at all?

Originally a 30-PICT *(can’t remember the revision offhand), but after a rebuild and tune, figured it was probably just worn out, and replaced it with a H30/31, that I had to fatten up the main jet (and possibly the pilot jet to get to run right.

Exhaust backfire may be caused by a slight exhaust leak near the cylinder heads. If it is, it will get worse, if it remains constant for a thousand miles there is nothing at all wrong with the car.

Currently working on a VW sand-rail project so am interested in this. Do not have any experience with VW engines but a fair amount on others. From what I have read there are four bolt on items; higher ratio rocker arms, better carburetion, extractor exhaust and mechanical advance distributor that really wakes up the VW engine. I have electronic ignition (MSD and Mallory) on two project cars. Supposedly they provide a longer duration, pulsating,  higher voltage spark over conventional points ignition. My opinion for what it is a better electronic distributor with mechanical advance can't hurt and is probably a good investment.