How to DIY 2x-plug

82SC · 02-20-2002, 08:19 PM

Well I am acquiring all the parts for my upcoming engine rebuild...

a 3.2L crank and conrod set it waiting for me at the machine shop...

and I may buy a set of 3.2L head from one of our members...

But I have been toying with the idea to go to 2x plugged...

What parts would I have to acquire?
is this a complicated procedure or is it something that once I have all the parts I can include it as part of the DIY procedure??

andial lists these parts:
AND 602 033 EX Distributor conversion, exchange
AND 602 702 00 2nd CD unit - Permatune
901 602 502 00 2nd ignition coil - Bosch
AND 602 907 01 Wiring harness for 2nd CD unit and Coil
AND 602 031 32 Complete 2nd plug wire set
AND 107 347 04 Special camline
930 106 326 01 Sheetmetal - not needed for Turbo engines

what is the special camline???
and are the 964 dizzy compatible with the SC???
I know nothing about 2x plugging!!!

Thanks

MJ

CamB · CamB's Garage

I know second to nothing about it.

If it were me (which it sort of is - more on that later), I would want to have matching cd units, coils and plug wires. But I am really anal about some things.

Also, what you set out looks like a pretty penny!! I think the Electromotive setup might be cheaper.

Steve Weiner at Rennsport Systems is very very knowledgeable about this stuff (and a very nice guy):

http://www.rennsportsystems.com/~porsche/2f.html

I am getting an SC based engine with a 964 dizzy. They dizzy has been modified to accept a MoTeC "chopper" plate. Ignition is controlled by MoTeC, with 2x Bosch ignition modules and 2x Bosch coils. To be honest, at the moment I don't know much about it and am pretty uncomfortable about saying what you can/can't should/shouldn't do.

Bob W. · Bob W.'s Garage

I twin plugged my 3.3 turbo engine a few years ago when I rebuilt it. The machine work was not expensive. The biggest expense is the ignition system. But there are some more details to be aware of.
The lower valve covers have to be machined for the lower spark plug access holes.
The sheet metal needs clearence holes punched in them for the spark plug wires.
Some head bolts will interfer with the spark plug wrench. The head bolts must be ground down a little (approx 3/16")all the way around the upper edge of the head bolts closest to the spark plug. Before you tighten the heads down install or remove the spark plugs and you will see where the clearence problem is. You have to do this while the engine is still out.
Also if you use different colored spark plug wires for the upper and the lower plug wires it will be easyer to make connections.

Bob W.

finadict · 02-20-2002, 09:12 PM

Its my understanding that unless you're running a high compression domed piston twin plugging is not necessary. When you have a large dome the flame spread is somewhat inhibited and 2 igition sources could be beneficial

Bob W. · Bob W.'s Garage

I have compared running the 3.3 turbo with single plugs and both plugs firing. There is definately a difference. The engine is a lot smoother with twin plugs-especially under a heavy load. Detonation, of course, is reduced.
However, I also feel (like most of us) that unless there is some compelling reason to twin plug; I don't think it is necessary on a street engine.(Read that as the bucks can be better spent on other things that would enhance the reliability.)
Consider twin plugging if you are going to run high compression or high boost on a turbo engine.
I think installing Raceware hardware, balancing everything, magnafluxing rods and crank, shot peening the rods should be done first. Perhaps shuffle pinning the case, mooning the cylinders and boattailing the main bearing webs could also be done.

Bob W.

82SC · 02-20-2002, 10:00 PM

well I was enlargening displacement and thinking about sticking with a regular CR like 9.5

but then I see these monsters like MMarsh and Randy's Iris and I get a wee bit jealous...so I want to run something higher like 10.8
and machine work is relatively cheap...it is the parts that are pricey...so if Ic an locate the parts for cheap...then...

but we will see...I am planning for a single plug engine rebuild...but if I can source the parts for a relatively good price why not!!!

MJ

Steve W from rennsport systems said:

> what parts and what would I have to do to double plug my SC project...I just
> saw a 964 distributor for 500...what other parts do I need...

You would need a donor SC distributor, that 964 unit, change the crank gear to
either 2.7 or 964, a set of custom Magnecor wires, and of course, the machine
work,...

so it sounds like if I take the 964 distributor route I will not need an extra CD cox...just another coil???

hmmm...

beepbeep · 02-21-2002, 01:53 AM

Just a question for you 2x guys:

How do you make plug-holes in bottom valve-covers? I saw lot's of pictures where bottom valve-covers are just drilled straight-trough which puzzles me. How do you keep oil from escaping? Do you need some sort of special seal around the holes?

Thanx!

P.S.

Ditch double CD units and go with Haltech or SDS...much better.

82SC · 02-21-2002, 02:00 AM

Haltech looks really rice-y to me...but I have heard good things as well...

so what is so bad about the CD units? I was thinking to just stay as OEM as possible...

what does an entire Haltech system cost?

TOO MANY OPTIONS!!!!!!!!!!!!! and opinions!!!!!!!!!

beepbeep · 02:45 AM

Rice-y or not, they are much easyer to handle...ignition systems are stupid things. Only thing they do is to fire a plug at certain moment.

Aftermarket direct-fire ignition doesn't need dizzy and lets you program ignition curves as you whish.

It will probably cost you as much as original equipment but with enhanced functionality.

I recomend using SDS or Haltech fuel-and-ignition ECU, you don't need to use fuel-drivers (yet). Those systems are using so called "direct fire" ignition which means that every cylinder uses it's own coil which gives strong arc.

You can use dual coils to lower amount of coils used.

Who cares if it's rice or not...it's 21'th century for god's sake... :-)
Info:

http://www.sdsefi.com

dickster · 02-21-2002, 02:42 AM

i was wondering about the oil escaping issue also...........

the dickster

ChrisBennet · ChrisBennet's Garage

I did some research on this when I did my twinplug 3.4 (from a 3.2). Definately check out Rennsport's web site for lots of info on this subject. Rennsport Systems

IMO, unless you are raising the compression, twin plugging isn't going to buy you much for all the expense (thousand$ I think).

The holes in the valve covers are in the "dry part" just like the upper plugs.

The 964 distributor turns the opposite direction from the 3.0L one BUT someone came up with a mod (check Rennlist) and I believe Steve Weiner (Rennsport) knows about it.

For the lower head stud nuts that interfere with the plugs I used 10mm nuts that measure 15mm across the flats. (Usual 10mm nut measures 17mm across the flats.)
-Chris

82SC · 02-21-2002, 07:27 AM

well if I do go to a twin plug system I will be running something in the 10.5 range for CR...depending on pistons...

but how expensive is this upgrade?
The machining is not too bad...
sounds like I can get a 964 ditributor for 300-ish
then I need a new gear (2.7 or 964) to drive the dizzy (how much??)
And an additional Permatune box...

As well as wires plugs etc...

hmmm...any first hadn experience?

Thanks

MJ

Paul Thomas · 02-21-2002, 10:13 PM

Forget the distributor, go with Electromotive. I have their twin-plug set up and love it. I go it from Windward, it came with everything you need to bolt it right up all the way down to a billet dist, hole plug. It isn't cheap but you'll probably save alot of time and crankfire is superior to the distributor setup. I had a real Bosch RSR set up, this is much better.