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Fri Dec 11, 2009 4:59 pm

I recently upgraded my 009 dizzy and points for a Bosch SVDA with electronic ignition. The carb is a 34Pict3 and coil is a blue Bosch. The motor is a stock 1600 in a 71 camper. I am thinking about replacing the coil for a high output one , such as a flamethrower, and opening the plug gap a little. Is this a good, bad or indifferent idea. The gap is now .025, and if its a positive for this engine, what gap should I use? Thanks in advance for any and all responses.

Fri Dec 11, 2009 5:30 pm

vwbuser71 wrote: I recently upgraded my 009 dizzy and points for a Bosch SVDA with electronic ignition. The carb is a 34Pict3 and coil is a blue Bosch. The motor is a stock 1600 in a 71 camper. I am thinking about replacing the coil for a high output one , such as a flamethrower, and opening the plug gap a little. Is this a good, bad or indifferent idea. The gap is now .025, and if its a positive for this engine, what gap should I use? Thanks in advance for any and all responses.

Bad idea. You will fry your electronic ignition module. They can only take so much current.

Fri Dec 11, 2009 6:02 pm

What you have is just about perfect.

Why do you feel the need for a change?

Fri Dec 11, 2009 6:49 pm

I concur to leave the plug gap at stock. This will grow as the tip wears.
No one is ever perfect anyway with gaps. A loose .025 with the feeler gauge may end up being .027 for reals. Then there is the beer factor...

Fri Dec 11, 2009 7:09 pm

She runs fine with the present setup, I was just looking for a little more kick. We load her up pretty good when we camp, but I won't mess with a good thing, thanks for the advice.

Fri Dec 11, 2009 7:14 pm

There is nothing wrong with getting a higher output coil. I'm running the 50k Flame Thrower from Pertronix with one of their ignitor pick up modules. I set the plugs at an easy .027 and it's probably almost .029 in real life.

Plus, and I have extensive data to back this up, With this set up and some MMO in the tank at each fill up I have gained 2 mpg. Dunno if it's the coil or the MMO or both but it's 2 mpg. There was no mpg increase from just the ignitor and the NGK B5ES

Fri Dec 11, 2009 7:24 pm

Quote: She runs fine with the present setup, I was just looking for a little more kick.

adding a bigger and meaner coil will do nothing more for you than a stock coil. The late Bosch coils were made to cut down on current draw so that points lasted a little longer. Once the spark occurs and the flame front ignites it doesn't matter whether 10,000V or 50,000V ignited it. The flame front moves at the same speed. You only need a higher output coil if you are running a wide gap and maybe 11:1 or 12:1 compression, which you would be nuts to do on the street. Modern cars have multiple high energy coils BECAUSE a single coil saturates at high rpms when you have 6 to 8 cyl AND the A/F ratios are much leaner. A 4 cyl won't saturate at street speeds and a late water cooled A/F ratio will destroy an air cooled engine at that RPM. A FI bus will run out of injection before it runs out of coil. A stock carbed and cam'd bus will run out of air before it runs out of coil.

Fri Dec 11, 2009 7:39 pm

It wasn't unusual to see spark plug gaps of .035 during the era of point triggered ignition systems. I would suspect that running that wide would do you no harm. It also might not benefit you much either. I have always stayed with a fairly tight plug gap when running points to lessen the duration of the arc across the point gap, but if I ever give in and go electronic I will probably go to a wider plug gap.

Fri Dec 11, 2009 7:51 pm

You left out flame kernel and ionization

Fri Dec 11, 2009 7:55 pm

Ignore all the nay-sayers and listen to me, my enlightened one 8)

Yes, an ignition upgrade and a larger spark plug gap to go with it, will help give your fuel a more complete burn. This equates to better gas mileage and even power gains (though not as noticeable). I did a lot of reading on this subject and it doesn't matter what you drive (diesels being the exception, of course), an improved ignition system will be beneficial.

I did a simple test with my Type III and a stock vs. higher output ignition system. Drove up a hill on the highway by my place in 5th gear (Gene Berg 5-speed ;) ) -- I just could keep the speed but couldn't accelerate. Next day, same time, same weather conditions, only change made was higher output ignition and a plug gap of .035". Up the same hill, same speed, same gear, same everything except the ignition changes, and I was able to accelerate up the hill! No pinging, either. But it really wasn't that much of a surprise to me due to all that I ready, it simply confirmed what I studied.

You want to make sure that your electronic points can handle the coil. The instructions with the points should tell you what you can use without damaging them. Also, adjust the gap to the smallest recommended setting according to the instructions and make sure everything runs fine. You'll likely need to adjust your timing a tad. When it runs good then you can open up the plug gap, about .005" at a time. Keep doing it until you get pinging then simply back the gap down .005" and you'll be golden ;)

Do it, you won't be sorry.

Fri Dec 11, 2009 8:06 pm

SGKent wrote: ... Once the spark occurs and the flame front ignites it doesn't matter whether 10,000V or 50,000V ignited it. The flame front moves at the same speed. You only need a higher output coil if you are running a wide gap...
Perfect information if you only read what I quoted. The larger voltage is for jumping the larger gap ;) A "meaner" coil with a stock gap is a waste, I agree.

Fri Dec 11, 2009 11:36 pm

Quote: Perfect information if you only read what I quoted. The larger voltage is for jumping the larger gap A "meaner" coil with a stock gap is a waste, I agree.

This works for Air Cooled Nut because he lives in an alternate universe where the laws of physics are different. Here in ours, the flame front is only ignited by the spark and not pushed along by it.

Remember the physics lesson in the movie where you have a room full of mouse traps loaded with ping pong balls and the guy throws one ping pong ball which cascades the whole room? The air and fuel that have been mixed is the room full of ping pong balls. Throwing a ping pong ball soft or hard triggers the whole room. If you go to a late water cooled motor that has a very lean mixture - like the mouse traps being fewer and farther apart, then throwing the ball harder allows it to hit more traps so you are guaranteed to set off a reaction.

I stand by the original statement. If your bus is tuned right you won't gain anything. This argument goes back to the 1970's when capacitive discharge units became available. They allowed points to last much longer as the points only give a trigger voltage and do not carry the current. A transistor circuit does. This saves the owner money by not having to take the car in so often to replace points. It also overcomes the wider gap on a plug as it wears so that the car stays in tune longer. However a hotter coil will just burn up the plugs faster.

Here is another solution - http://germansupply.com/home/customer/product.php?productid=16482&cat=296&page=5

Fri Dec 11, 2009 11:45 pm

Wait, if the flame front is only ignited by the spark, and not pushed along by it, would that mean that triple electrode spark plugs yield no benefit over stock ones??

Fri Dec 11, 2009 11:47 pm

SGKent wrote: I stand by the original statement. If your bus is tuned right you won't gain anything.

I stand aside a little bemused. I mean, 7.3:1 compression ratio, a horsepower peak of 4,200 rpm, and a combustion chamber barely more efficient than a Briggs & Stratton lawn mower. I have never seen a VW *correctly assembled and tuned* that was unable to fire itself adequately. I always rationalized occasional misfires as a holiday for the exhaust valves . . . :D

Fri Dec 11, 2009 11:57 pm

Quote: Wait, if the flame front is only ignited by the spark, and not pushed along by it, would that mean that triple electrode spark plugs yield no benefit over stock ones??

Nica - think about it. With 3 electrodes the shortest gap would spark and wear away until all are the same gap. Then each electrode would carry 1/3 the current which means they would last at least 3 times as long. Instead of replacing them every 15,000 miles you would be replaceing them every 45,000 miles. That is all you are saving - staying tuned up longer and saving on maintenace. A hotter coil will jump a wider gap but it also wears that gap faster and carbon tracks sooner.

Quote: I always rationalized occasional misfires as a holiday for the exhaust valves . . .
Colin - very cute and thank you for making my point.

Let me add this. There is some perception among people who have never dyno'd engines that there is some sweet spot where suddenly horsepower comes freely and all the problems in the world go away. Some day everyone should spend some time on a dyno tuning engines. The differences between runs because of temperature, humidity, atmosphere pressure and variances in the dyno are greater than one degree timing and spark voltage changes etc. If someone wants to spend a small fortune trying to pick up those gains it is certainly their choice but a wiser decision would be to pop some popcorn and spend an evening watching a movie with your bride or babe. And when you get old you will remember that popcorn evening long after you have forgotten the performance gains you didn't get from that coil on your VW.

I am off to bed, that nurse is calling again. We have to finish the upgrade of 600 users to Windows 7 tomorrow. Cathy has a cold and I don't want it.

Sat Dec 12, 2009 12:02 am

aaaahhh :lol:
I will be buying some of those then!

Sat Dec 12, 2009 12:05 pm

OK, so a high output coil allows for a larger gap, which creates a larger spark, which is NOT beneficial to the performance of a stock 1600 motor.
Their use is more of a requirement on a higher compression engine, which needs the extra gap/spark?

Sat Dec 12, 2009 1:11 pm

SGKent wrote: Quote: Perfect information if you only read what I quoted. The larger voltage is for jumping the larger gap A "meaner" coil with a stock gap is a waste, I agree.

This works for Air Cooled Nut because he lives in an alternate universe where the laws of physics are different. Here in ours, the flame front is only ignited by the spark and not pushed along by it...

Well, aren't we being a bit of a prick :roll: Here's some info: I do have a good understanding of physics, am open to further education, and didn't stop learning after high school. You need to brush up on your reading comprehension because I wrote that the higher voltage allows the spark to bridge the LARGER GAP :roll: The width of the plug gap that a spark can jump is proportional to the output capability (voltage) of the coil. Why is this so hard to accept?

Here's some references:
www.globaldenso.com
Quote: The spark plug generates a flame kernel
from a spark which then ignites the fuel
Igniting the fuel with an electrical spark occurs because fuel particles
situated between the electrodes are activated by the discharge spark to
trigger a chemical reaction (oxidation), the reaction generates heat, and a
flame kernel is formed. This heat ignites the surrounding air-fuel mixture until
a flame core is formed that spreads combustion throughout the chamber.
However, the electrodes themselves absorb heat which can extinguish the
flame kernel, called the “quenching effect.” If the quenching effect between
the electrodes is greater than the heat generated by the flame kernel, the
flame is extinguished and combustion stops.
If the plug gap is wide, the flame kernel will be larger and the quenching
effect is reduced, so reliable ignition can be expected. But if the gap is too
wide, a large discharge voltage becomes necessary, the limits of coil
performance are exceeded, and discharge becomes impossible.

Great reading:
Ignition Basics
Quote: One way to improve combustion efficiency with any engine is to increase the spark-plug gap. This requires a higher voltage spark, which can do a better job of igniting the mixture, especially at idle. This comes at the cost of greater demands on the ignition system. Performance inductive and CD systems can handle larger plug gaps of up to 0.045 to 0.055 inch, but this demands excellent performance from the entire secondary side of the ignition system (coil wire, cap, rotor, and plug wires) because of the higher voltage required to jump the wider gap. Typically, this also increases the amperage demands on the ignition system as well.

I think I proved my point.

Sat Dec 12, 2009 1:27 pm

SGKent wrote: ...
Quote: I always rationalized occasional misfires as a holiday for the exhaust valves . . .
Colin - very cute and thank you for making my point.
Your point being ignition inefficiencies? I know Colin is a smart dude (and great with illustrations) and wouldn't be encouraging power and fuel inefficiencies. A misfire indicates a problem with the ignition system. Is that what you're encouraging?

SGKent wrote: Let me add this. There is some perception among people who have never dyno'd engines that there is some sweet spot where suddenly horsepower comes freely and all the problems in the world go away. Some day everyone should spend some time on a dyno tuning engines. The differences between runs because of temperature, humidity, atmosphere pressure and variances in the dyno are greater than one degree timing and spark voltage changes etc. If someone wants to spend a small fortune trying to pick up those gains it is certainly their choice
His name is Jake Raby :lol:

SGKent wrote: ...but a wiser decision would be to pop some popcorn and spend an evening watching a movie with your bride or babe. And when you get old you will remember that popcorn evening long after you have forgotten the performance gains you didn't get from that coil on your VW... :lol: Really, because of Alzheimers disease? I do both, spending time w/my sweetie AND educating people on what I know and experienced so they won't get misinformed on the performance gains I realized on my air-cooled VWs.

Oh, and speaking of one's profession, my line of work is business intelligence reporting, automation, and application development. So I'm not some kid flippin' burgers with barely a high school education.

Sat Dec 12, 2009 1:29 pm

vwbuser71 wrote: OK, so a high output coil allows for a larger gap, which creates a larger spark, which is NOT beneficial to the performance of a stock 1600 motor.
Their use is more of a requirement on a higher compression engine, which needs the extra gap/spark?
A larger gap is beneficial. Remember that VWs were built as inexpensive, yet functional, as reasonably possible. The stock system is fine, I agree, I've used it for years. But like many things it can be improved with the advancements of technology.