3.0 Race Car Ignition Help

[North Coast Cab]

I have a 3.0 with webers for my race car and I need help on designing the ignition. It is a single plug set-up, and I have no distributor or coil or anything. I really don't know all the crazy details on ignitions and could use some basic help.

Thanks, John

[Early_S_Man]

John,

Which vintage 3.0 do you have? '77 or earlier with 6-bolt crank & flywheel, or later 9-bolt crank??? The answer is critical as to which distributor you can use, unless you are building it up yourself ... then, you can select which distributor drive gear to use.

[North Coast Cab]

9-bolt crank
10:1 compression
I'd like to look at a stock set-up and then an aftermarket one.

Thanks for the help, John

[Walt Fricke]

Well, why not try an Electromotive (HPV-1?) ignition only unit (you don't need the EFI part). I have a pair of them on my race motor and they are basically bombproof as long as you don't let the sensor slip into the toothed wheel it reads. You sometimes find these used as guys upgrade to EFI that does the ignition also, so they don't need the older ignition only units.

That will solve your coil and distributor problems, and with Webers I guess you aren't looking for any period authentic look.

Walt Fricke

[North Coast Cab]

Thanks Walt. So the HPV-1 ignition module acts as the coil and distributor. What connects to the flywheel? I have the 3.2 OEM sensors if that helps or do I need to buy somehting else? Also, if you don't use a distributor what do you plug the hole with?

[Early_S_Man]

John,

For the 'stock' setup, I suggest a used or rebuilt '78 - '79 distributor, used or reconditioned OEM SC 6-pin Bosch CDI unit, and used or NOS, black Bosch 0.221.121.001 coil [may be replaced with MSD epoxy-filled High-Vibration coil #MSD-PN8222] ...

[North Coast Cab]

I just printed the MSD 6AL manual and the Permatune manual as well. Weekend reading.

[Early_S_Man]

John,

Here is some reading material on the factory CDI ... good enough for RSRs!

'73 R&T RSR vs 911S Track Test ...

6-pin SC/Turbo CDI unit repair documentation

[crashmy911]

won't he have problems with 10 to 1 compression running single plugs?

[Walt Fricke]

Originally posted by North Coast Cab
So the HPV-1 ignition module acts as the coil and distributor.

Right you are - it does both. It has three coils on a plate with some adjustable pots for timing, each coil with two posts for wires to the plugs. When one plug fires at the proper time, another fires at an "improper" but harmless time - called a waste spark system.

What connects to the flywheel?

Nothing, but you have to add a toothed wheel to the crank pulley, which tells the unit's sensor mounted nearby what is going on. With a waste spark you don't have to figure out whether a crank is at 360 or 720 degrees, if you follow me.

I have the 3.2 OEM sensors if that helps or do I need to buy somehting else?

Don't think you can use these.

Also, if you don't use a distributor what do you plug the hole with?

A plug (sorry, couldn't resist).
Sellers of these as kits often provide one. Try Clewitt for starters, or Racer Wholesale Parts (if Pelican doesn't carry any of this). Easy to make if you have a lathe, and the distributor holder/adjuster stud nearby is convenient for holding a plug in place if just an O ring isn't enough.

Walt
(if I knew how to intersperse comments with quoted material so the type differentiated things I would have - sorry)

[North Coast Cab]

Planning on mixing 93 & 100 octane fuel.

Warren,
Nothing against the OEM solution, just looking for options before I plow ahead.

John

[North Coast Cab]

Ok, after reviewing options and factoring in economics I'm leaning towards an MSD solution. MSD-6AL 6420 ignition control & Blaster SS coil. Is it worth while to install a timing computer like the MSD-8980/8981 as well? This is assuming I can find a good 3.0 distributor reasonable. Otherwise, it looks like the Electromotive XDi set-up would be best since it is expandable to twip plug easily.

Thanks, John

[North Coast Cab]

Ok,
I sourced an '83 SC distributor, MSD 6AL CDI and MSD Blaster Coil. I've read about re-curving distributors and I'm wondering if that is something I have to do for this motor. If so, where would I get this done.

John

[cstreit]

John,

I'd look into recurving it.. In fact you're probably going to do several iterations of this to tweak your power curve to the max allowed. Are you running GTS3 or 4 next year?

[North Coast Cab]

Where/who would do the recurve and how do I specify my needs? Not sure on the GTS class yet, hoping for 3.

[cstreit]

John,

The only place I'm sure that does it is REnnsport, there may be others. Since you're at a higher compression rate you can either adjust your advance down a little in order to run less octane, or maybe move it up if you're going to run race gas.

I'm not sure I have great advice about the curve you'll want as the 10:1 and higher engines I've done have been twin plugged....