Twin plugging - how much $$$

dd74 · 11-25-2006, 05:38 PM

Just wondering, but what has been the general dollar cost of drilling the heads, the distributor, and anything else involved in twin-plugging a 911 engine?

Thanks.

mb911 · mb911's Garage

I was wondering to. I think the machining is the cheapest part probably 50 dollars per head???????

Formerly Steve Wilkinson · 11-25-2006, 05:58 PM

Ask Steve Weiner--porsche@rennsportsystems.com. He does a fabulous job of it, and it's not at all "expensive." Of course twin-plugging is just a small part of an engine "system," and asking what twin-plugging alone costs is sort of like asking what a carbon-fiber front hood for an otherwise box-stock 911 costs.

Basic question would be why do you want to twin-plug?

Jeff Alton · 11-25-2006, 06:21 PM

I pay 300ish (sublet costing) for the machining including the lower valve covers. Then you need to do the electrical part. Used 964/993 distributor is 250-300, andial splitter is just under 600 (or maybe loren will actually tell us how you can use the 993 set up for around 120.............. ) Then the second set of wires.

Or you go crank fire and either by a whole kit or piece it together yourself using used stuff on the market. IIRC I sold a hpv-1 setup for around 350 ish not long ago with everything but trigger wheel and plug wires. I have been using going superfast instead of clewett for the pulley, sensor and bracket for cost reasons. Then you need a full set of wires as they usually have different ends at the coil. If you buy a kit I would recommend an XDI complete set up from Clewett. I think one sold recently on the Pelican classifieds for 65 cents on the dollar.

Or, bite the bullet and go EFI at the same time..................

Cheers

dd74 · 11-25-2006, 07:08 PM

Quote:

Originally posted by catca
I pay 300ish (sublet costing) for the machining including the lower valve covers. Then you need to do the electrical part. Used 964/993 distributor is 250-300, andial splitter is just under 600 (or maybe loren will actually tell us how you can use the 993 set up for around 120.............. ) Then the second set of wires.

Or you go crank fire and either by a whole kit or piece it together yourself using used stuff on the market. IIRC I sold a hpv-1 setup for around 350 ish not long ago with everything but trigger wheel and plug wires. I have been using going superfast instead of clewett for the pulley, sensor and bracket for cost reasons. Then you need a full set of wires as they usually have different ends at the coil. If you buy a kit I would recommend an XDI complete set up from Clewett. I think one sold recently on the Pelican classifieds for 65 cents on the dollar.

Or, bite the bullet and go EFI at the same time..................

Cheers

My engine is complete - a 2.7 with Webers. But I have some fairly high compression and though it doesn't continually ping, when the weather is hot (or the heads are hot from being in traffic), at high RPMs and WOT, there is some rattling going on.

So, I'm at a loss as to which of your three examples is the better and most cost effective.

Oh, and will either of your examples increase horsepower?

randywebb · 11-25-2006, 07:12 PM

Steve Weiner's web page explains that the twin plugs themselves do not incr. hp - it is the ability to incr. the compression raito that gives more hp. Also you can incr. plug gaps and get a few.

I would for sure do the drilling if your motor is out - not that much. You can add the electronics later on.

The dist. cost above seems low to me...

Jeff Alton · 11-25-2006, 07:18 PM

No matter how you do it, the end result should be the same. The most cost effective way would be crankfire (used). Another option I forgot was one of Henry's twin plug dizzy's. If you are getting any detonation now, it would be money well spent.

Randy, I have bought and sold 4 different 964 diistributors, I never paid or sold one for more than 300. Mind you, the last one I sold was 18 months ago.

Cheers

dd74 · 11-25-2006, 07:32 PM

I'm a bit ignorant of crankfire, Jeff. Could you recommend a few systems?

randywebb · 11-25-2006, 07:45 PM

OW! I paid $800 (with wires) for a dual distr. from a dismantler -- that was a few years ago tho.

Jeff Alton · 11-25-2006, 07:48 PM

The more I read my own posts the more I realize I am not doing a very good job here

IF you want crankfire and want to buy new I would call up Clewett and a get a complete XDI system. He can sell you everything you need. Pelican may also be able to, not sure though. If you want used I would look for an HPV-1 set up. It is an older unit but it is all contained in the DFU's (coil packs)

You may also search out some of the efi computor makers to see if they offer ignition only solutions and then make up your own coil pack. This would be another way to do the crankfire thing.I can send you pics and part numbers to do make the coil pack. I haven't looked lately at too many as I am using a Microtech that does not do ignition only. But you could try Haltech (timT or GTU935 on pelican) or Motec or any of the others.

You may also consider one of Henry's distributors (or one from carquip, JBracing or contact MBurns for the one his company markets) These provide the "look" that the cranfire does not. I really like the idea of a 12 plug RSR style distributor on a motor with carbs.

All that said, the simplest may be to just call Clewett and get it all at the same place, Richard is easy to deal with and willingly answers questions.

My guess is that if you go new, either the 12 plug distributor or crankfire will both be with in a couple of hundred bucks of one another when all is said and done.

Hope this helps.

Cheers

Jeff Alton · 11-25-2006, 07:51 PM

Also, lets get Randy to describe his system. My guess is that it is a 964 distributor with internals from an earlier distributor and fired by one or two MSD boxes. The guys is Oregon (steve, dick and gamroth) I think have done a few of these. It may also prove a good option provided you can get a good price on a 964 distributor.

Cheers

randywebb · 11-25-2006, 08:03 PM

Yup - guilty as charged - the internals are from an SC. Dick Elverud has a big pile of discarded distributor bodies by his barn. Someday an alien archaeologist will dig them up and think he's found a shell midden or something...

dd74 · 11-25-2006, 08:08 PM

Does crankfire require machining the heads?

randywebb · 11-25-2006, 08:08 PM

ugly but effective -- I'd like a 12 plug cap/distr. but they were far too spendy when I did this. Need to clean up the dual coil mounts too...

randywebb · 11-25-2006, 08:09 PM

you always have to machine the heads - that's how you get the extra plug in there

... unless you buy a 3.6L motor - there, P AG already machined the heads.

Steve@Rennsport · 11-25-2006, 08:11 PM

I would simply add that IMHO, the current crop of crank-fired ignitions do not run as well as an MSD setup on carbureted or MFI-equipped motors.

If you use EFI, then the good crank-triggered stuff (Motec) is very well done.

Steve@Rennsport · 11-25-2006, 08:14 PM

Quote:

Originally posted by dd74
Does crankfire require machining the heads?

To install twin-ignition (dual plugs), the heads must be machined to accept the lower plugs and this applies to all 911's.

This applies to crank-fired as well as distributor setups.

dd74 · 11-25-2006, 08:22 PM

Steve - I emailed you at Rennsport.

Thanks.

89911 · 11-25-2006, 08:25 PM

I don't know if anyone answered your question? These number are off the top of my head from memory: 964 distributer $6-700, Andial Splitter $5-600, Additional harness $250, Addition Coil $75, Machining (Hard to say since it was inclusive of other work), $500. Labor, done by myself. I figure around $2000. A poor stand alone upgrade, but I did this with higher compression 3.4 Mahle P/C's.

Jeff Alton · 11-25-2006, 09:14 PM

Quote:

Originally posted by Steve@Rennsport
I would simply add that IMHO, the current crop of crank-fired ignitions do not run as well as an MSD setup on carbureted or MFI-equipped motors.

If you use EFI, then the good crank-triggered stuff (Motec) is very well done.

Steve is the expert, no doubt. (I have picked his brain countless times on the twin plug set up stuff!) This leaves you with a 964 distributor set up (like Randy's) or one of the other special 12 plug distributors I mentioned earlier. Both of these allow you to fire them with the MSD which is what will allow the larger plug gaps etc...

At any rate, calling Steve is a good move!

Cheers