Ignition systems

[Guest]

Guy's, I am due to get my new motor (347 stroker with rousch heads etc)in a few days with any luck, and want some advice on the best way to go for ignitions setups.

At this stage I am planning using a Wolf 3D (Ver 4?)management system on my RFGT40. I will be using a 4BBl throttle body on an edlebrock manifold at this stage. I am also using a "V" belt setup with the RF supplied pulleys.

The questions are this :-

1. Will a standard ford / mallory type distributer fit in the engine bay ? (there is a cross member under the BHD window that concerns me.
2. What coil set up would be best single or multiple ?
3. Are amplifiers needed ?
4. Do i also consider a crank sensor trigger arrangement?

Building the car is the easy bit for me, It is this kind of stuff that has me confused. There again any more than two wires and I am outa there.

Any help here would be appreciated.

 

Hi Rick

I don't know if the standard distributor fits. I have heard on some kits you have to get a smaller one but I'm not sure about the RF. Maybe some one else has their engine in and can comment.

Single/multiple coils is something I can talk about. I will probably get some arguements but according to the text books multiple coils are superior. The reason is fairly simple. With one coil the time available for the coil charge and discharge is signicantly less than a multi coil setup. With a multi coil setup typically each coil feeds 2 cylinders. They only have to fire once each engine revolution. A single V8 coil has to fire 4 times each revolution.

Most modern ignition systems have some form of amplifier. For single coil systems they were called things like MSD etc. In the multi coil systems there is one for each coil and the are usually called igniters (and they are expensive). Some coil packs have igniters them built in (see Commodore V6s for example). This is neat but the igniters are more reliable when they are separate and not mounted on the hot vibrating engine.

If you are using multiple coils driven by the engine management you normally go with a single crank angle sensor (or sometimes more than one) The engine management system these days needs to know where the crankshaft is and what point in the cycle it is. To do this on the Windsor engine usually use a single crank angle sensor and a cam sensor as well. Between the 2 of them this can be calculated accurately enough.

Hope this helps a bit. I can waffle on a bit more if you like, but thats probably enough for now.

John

 

[Gary Gibbs]

www.electromotive-inc.com sells a distributorless system that has very fine adjustment through computer control (64 point linearly interpreted surface of RPM vs. manifold pressure).

 

[Paul Thompson 'Hooligan']

Hi Rick
I'm with John on this one. We use 8 Bosch coils on Roy Smarts GTD with Motec management. The coils allow nice short neat plug leads which in turn reduces lead losses. Also, as John states, using more coils allows each more time between sparks which allows fatter sparks and less chance of plug fouling.

For double ended coils, the system is a 'wasted-spark' design where cylinders fire on compression and exhaust. Depending on your firing order, this usually means leads still have to reach across/round each side of the block though.

With the 8 coil setup, we have two sensors, one on the crank and one on a 'cut down' modified mallory distributor, which only acts as a drive to oil pump from cam and gives phase of cam to ECU, thus enabling the ECU to fire the correct individual coil without wasting sparks.

For a race car, there is another consideration in that if a coil fails, you drop a cylinder, NOT THE RACE..

I have added acouple of pics below which have been posted before, but as a reminder.
The first shows the ECU + to the right, the two ignition amplifiers marked 1-4 and 5-8.

The second shows some of the coils mounted to the inner engine bay chassis rails.

As you can see, wiring although straight forward, is not for the feint-hearted!!

Since installing, the car is much more responsive and has not fouled plugs.

Hope this is of interest, good luck with your installation and setup.

regards

Paul Thompson
[email protected]

 

[Gary Gibbs]

Thanks for the info Paul. I see that Motec permits multiple coils. What other systems out there provide for multiple coils besides electromotive and Motec?

 

[Dave Wharran]

Did mine with a Haltech E6K. Not as many bells and whistles as Motec, but only 1/3 the cost.

4 coils, wasted spark. Coils are Delco/Motec with igniters built in

4 magnets in flywheel (one magnet is s pole for home and trigger of #1 cyl, other 3 magnets are n pole for trigger signals only for other 3 coils)
Flywheel is steel in this picture. Magnets are set in custom stainless holders. Magnets work fine with the steel flywheel, but just got a good deal on an aluminum one that I couldn't pass up!

Hall switch has 2 outputs, one for home, one for trigger. Blue bracket is custom built aluminum piece(s).

Original intermediate plate was steel and ran VERY close to the magnets. I redid it out of aluminum and cut a .030" deep groove for for magnet clearance. Also had to mill a clearance slot in the starter mounting flange. It's tight in there! Not much room to spare. Just had to personalize the piece a bit too.

All timing is done in software. No signals needed from a distributor at all. Whats left of it is there to support the bearings so it can drive the oil pump. Engine has been run on the dyno with great results. Ignition timing is rock solid.

Dave

 

[Guest]

Thanks guys,
Hope all had a great Easter.
It looks like coil packs are the way to go.
Any suggestions on specific brands or types?

Cheers,
RV

 

Rick

I don't think it will matter much as long as they are compatible with the ECU. Talking to the Wolf people may be useful to see if they have a preference. Otherwise it will depend on your budget as much as anything. You can go for an elaborate systems like Pauls (and that did sound good) or something simpler. If the igniters are separate I would suggest you get the coils and the igniters as a set.

If you want to try a wrecker for second hand production bits, you could get one 8 cylinder coil pack or two 4 cylinder ones. The results will be similar.

John