early ignition ideas....

lateapex911 · 03-03-2003, 06:38 PM

My search continues!

First, I wanted to ditch the points...just the crude nature of them seems, well, unseemly!

Anyway, got some good advice here on the early favorite, the Pertronix, and have begu leaning away from it due to performance and reliability issues.

And as my engine (a 2.7 based on an early alum case) has a early Bosch distributor, I'd have to replace IT too. Uggh.

My engine builder, a great guy, who always knows best,(but my wallet can't always keep up with him!) suggested tossing the whole mess, and installing the Electromotive HPX system.

I like the idea, but the $1000 dollar price tag doesn't sit well!

I see the advantages, but I'd love to get some feedback from you folks. Has anybody used it? And tips or insights?

The specs are: 2.7 with Webers, SSI exchangers, sport muffler and Solex cams.

Thanks,

mskala · 03-03-2003, 06:43 PM

Jake,
Why would you need to ditch the Bosch dist to get
an optical or hall ignition? I've never heard that the
early ones don't work with the aftermarket units.

But don't count me as having done it, I have the
Marelli (with a non-standard optical unit)

Mark S.
'70 914-6

jmz · jmz's Garage

no prob

lateapex911 · 03-03-2003, 06:50 PM

It was my understanding that the Pertronix unit doesn't fit the early (pre '72) units. (According to my call to the Pelican gurus) Now, the Alison/Crane unit may be different, I've just started researching them.

Perhaps the system could be Crane XR 700 to an MSD 6Al to the MSD blaster 2 high vibe coil.

Or the electromotive setup.

I wonder how much better the Electromotive setup would be. Better spark at high revs, but not sure about lower revs.

jmz · jmz's Garage

I think the 73 type like the rs would use will support the pertronix.

TimT · 03-03-2003, 06:57 PM

Perhaps the system could be Crane XR 700 to an MSD 6Al to the MSD blaster 2 high vibe coil

That set up works really well

I installed an crane (nee allison) optical triger on one of my cars about 15 yrs ago it has worked without fail for all this time. I sold that igniton to a friend when I installed twin plug system.

Another idea would be to get a SC dist with a hall effect trigger to fire the MSD.

get some good spark plug wires while your at it.

lateapex911 · 03-03-2003, 06:59 PM

I think you're right, the RS would be a good choice, but the math becomes an issue:

Dizzy: 440 or so.
Pertronix: 80 plus-minus
MSD 6AL 230
Coil 50
Total: 800

vs the Electromotive at $979

(I know I could continue using my CDI, but it's been troublesome, and I would like to replace it. (But not at over a thou!)

lateapex911 · 03-03-2003, 07:01 PM

Tim- I was hoping you'd show up!
I read in another thread that you installed an Electromotive unit...true? Good? Bad ? or another model?

TimT · 03-03-2003, 07:24 PM

The electromotive units work just fine, others have differing opinions though. You can fit the crane trigger in a bosch dist, or you could buy a used SC dist and use that trigger. I know alot of people use the pertronix, but a few negatives always sway your opinion.

Seems like the most economical way for you to go would be the MSD route. It works well and has been done a zillion times

My little project keeps changing, Ive decided to use EFI on my 2.2. So the HPX went somewhere else. I bought a trigger from Clewett, and a EMS from aother supplier. This weekend I put the coil packs and harnesses together.

If you do go with a electomotive unit make sure you use resistor plugs, and well shielded plug wires. Cross talk fropm the wasted cylinder can cause interference with the ignition.

911pcars · 03-03-2003, 09:46 PM

Jake,
I'm not sure what the extra $1000 is going to get you in the way of add'l performance. You didn't specify having a high compression ratio or twin plugs to fire; "merely" a nice single plug 2.7 that may not need any extra spark. Does the engine run okay? Many engines just like yours have done quite nicely with the addition of a pointless system of some sort (Pertronix, Crane or factory) and an induction-type or CD box for added voltage capacity, multiple sparks, smoother idle, etc.

If you already have a Bosch distributor, you can install a pointless system (and coil) for less than $200-$250 in parts and be assured it will supply the spark you need. I can't speak for a Pertronix, but the Crane optical unit fits fine in my '67-vintage S distributor. I also have their HI-6s box - on an engine that is similar to yours. Unless your engine really needs the extra spark, I don't think this add'l money is worth spending to get there.

Steve Weiner at Rennsport has some good information on the subject:
http://www.rennsportsystems.com/2a.html

Sherwood Lee
http://members.rennlist.org/911pcars

jmz · jmz's Garage

I don't think you need anything more than your bosch cd box or permatune unless you've got some really domed pistons and need the extra spark travel. I ran a 2.7 w/ rs pistons, solex cams and weber 40's for many years w/ a stock bosch distributor (74) w/ the mechanical advance disabled. The optical points weren't available back then or I would have installed a set.

Some people have suggested using an sc distributor but they spin the wrong way (at least the 80-83 models) I currently have a 3.0 w/ msd and a re-curved sc distributor on a moderatly high comp engine w/ mod s. cams. I went this route b/c I needed something as my old rs distrubutor and early cd box wouldn't work on a 3.0 unless I changed the dist. drive gear on the crank.

JMZ