Aircooled VW South Africa

The Beetle in the background. Has its rain gutters been removed? + roof chop?

That looks like a complete fiberglass shell. So yes, roof chop and no rails...

Pine wrote:Nice meeting you too, sorry I missed the startup! Below a few pics of the beast, kinda weird to see it without a dizzie

Bugger, the quote option doesnt include the pics....

Oh well. My question is this.... If you look at the first engine pic, there on the stand you have a "dashboard" with rev counter etc. Does anyone have a wiring diagram for one of those. I have had one now for AGES, with a on/off switch, push button start Rev couner etc. But I havent yet figured out the wiring(have I said already that wires aren't my speciality?? Give my a hammer/dolly and a spraygun instead. erm.... add to that a welder Mig/Tig and grinder too!!!!! )

Thanks in advance.

That engine is looking awesome.

Please explain how a "dizzie-lis" engine works.

Chris wrote:Please explain how a "dizzie-lis" engine works.

Were those pics taken @ the volkspares workshop

YvaneS wrote:Were those pics taken @ the volkspares workshop

Yip

Chris wrote:

That engine is looking awesome.

Please explain how a "dizzie-lis" engine works.

The toothed wheel mounted on the crank pulley has 60 teeth of which two were removed at about 40 degrees BTDC hence it is called a 60 - 2. A hall effect sender (You can use a magnetic type as well but it doesn't send a signal to the ecu reliably if there is insufficient voltage) is mounted at the tdc position on the crankcase. This sender counts the number of teeth moving past it during 1 revolution of the crankshaft.

The ecu uses this information to determine the crank angle and thus which piston is at tdc at any given moment. By computing the tdc position of a given piston at any given time during the cycle the ecu sends an electrical impulse to the coil pack which then fires the required spark plug.

The reason for the two missing teeth is to give the ecu an indication of TDC on piston No.1 however because there is a lag between the sensor picking up the missing teeth and the ecu being able to process the fact the missing teeth are taken out about 40 degrees before TDC. This gives the ecu time to send a signal to the coil pack to fire a given spark plug on a given cylinder.

Because the sensor and ecu have so many reference points i.e. the teeth on the wheel I can adjust the timing on the engine to an exact value at any given rpm. Let's say I want to advance the timing to 16deg BTDC at 2000RPM then the input from the sensor would allow me to do this via the programmable ecu (In this case a Gotech Pro-X) The sensor and wheel combination would then also allow me to advance the timing to 32Deg BTDC at 2500RPM. This IMHO is a far more predictable and tuneable way to advance timing than a distributor, especially since the newer chinese 009's tend to differ greatly in advance curves from one to the next.

Sounds great. But my question is more to do with the "coil pack". Does it fire each plug individually or does it fire each plug twice during each 4-stroke cycle, i.e. once every crank revolution, like motorbikes do? I guess you would need two coils, one firing 1 and 2 at the same time and one firing 3 and 4 at the same time, or something like that...

I really love the idea of being able to program the advance curves straight into the ecu. I wonder what the catch is... i.e. why all the modern cars don't use it... or do they? Spark plug life?

Thanks for the explenation.

What I also like about it is the that it makes the engine look clean.

Ron&Gill wrote:Sounds great. But my question is more to do with the "coil pack". Does it fire each plug individually or does it fire each plug twice during each 4-stroke cycle, i.e. once every crank revolution, like motorbikes do? I guess you would need two coils, one firing 1 and 2 at the same time and one firing 3 and 4 at the same time, or something like that...

I really love the idea of being able to program the advance curves straight into the ecu. I wonder what the catch is... i.e. why all the modern cars don't use it... or do they? Spark plug life?

On this particular setup it does fire on two cylinders simultaneously so you were correct in assuming this. This system is also known as a wasted spark ignition system. This system is basically two coils in one casing. However should I wish to do so I can "upgrade" to individual coil packs where the system fires each coil individually.

This really isn't rocket science as the software for the ecu is very user friendly and easy to understand.

Most modern fuel injected cars make use of a toothed wheel to detect the crank angle whilst a high percentage of the more high performance vehicles also have an integrated knock sensor that allows the ecu to advance the timing till just before pre-ignition occurs thereby getting the most energy out of the available fuel.

Ah yes, I suddenly remembered, I have a system like that too.... on my RIB... 3 cyl, 2 stroke. Thanks for that, but most engines retain the dizzy though to stay away from the "wasted spark", don't they? I know the toothed wheel for fuel injection timing. I don't know, it has been many years since I've looked under the bonnet of a new car... I mean, I lifted the cover off the boat engine last leave and went "whooaa!", took a pic quickly before something broke and closed it again...pheeuww!!

Hey,
I was at Volkspares on Saturday afternoon, hear the noise, breathed the fumes, said howzit to Rui and then left! Didn't realize it was your engine chocking up the shop!!

I have a modified distributor that can do the wasted spark thing. Basically two hall effect sensors with an additional cut out in the rotating part. That fires 4 individual coils via TCIs.

I must admit it is a bit tempremental.

That's the reason I switched to the MicroTech with 60-2. a Lot more reliable. I'm using 4 individual twin spark coils firing the 8 plugs. The coils are driven by MicroTech ignition drivers. With the wasted spark bit as well.

As said, a lot of modern cars use this system, they will also run batch fuel injection. To move one step up to sequential injection and also "normal" spark plug firing, they often use a pickup on the camshaft gear to indicate which point in the 4 stroke sequence the engine is. The VW guys do this by keeping the dizzy and using it purely as an indication feeding the ECU to tell it the position in the 4 stroke sequence.

Awsome looking & sounding engine, saw many smiles when it started up, like christmas day when Santa brings all the nice gifts.