twin plug discussions....

[ALB]

hi bj-
I've also been looking into twin plugging (type 1 82x94, engle fk10 or fk46( 300 degrees duration, lots of lift) cam, 42 x37 semi hemi heads by Gene Berg).

From what I've ungerstood, twin plugging is most beneficial in bigger bores (94mm and up). Also, the wilder the cam, intake and head combination,the more benefit. I've been in contact with Craig Paton in Australia ( i don't know if he posts here) and he claims to have talked to
customers of Stan Pabjoy (who does a distributor that looks like volkaholic's- it probably uses the same Nissan cap and rotor) who all rave about it. Stan is a machinist and has been playing with dual ignitions for type 1 motors for several years now, and he claims way more low end and midrange torque. Craig told me about a guy with a type 1 in a bus that now climbs hills in 4th gear that he had to downshift into 3rd before.

Some of Stan's engines are used in bugs for hillclimbs ( a popular sport
in Aus) and according to Craig, the twin plug mod is good for 2-3 seconds
on a minute long course. If you know motorsport, you know that's a big deal. I've been in contact with Stan via email and he claims it's one of the best mods you can do.

I've also been in contact with volkaholic and have been waiting to hear
about his dyno results. The motor (iirc) is a stock stroke , 90.5mm bore and mild camshaft (270ish degrees?)in his son's first car and I don't think the best combo to properly showcase the technology. I'm not trying to slam volkaholic; I'm very interested in what he's done. I just think he needs to build a bigger, wilder motor to show the potential of what he's created.

Type 1 motors have been used for 40 years or longer in airplane applications and twin ignition systems are the norm for safety. I think Stan
told me dyno tests of these motors didn't show any power increase and i think this is why so few people have played with the idea. From what i've been told, motors with 290-300 (advertised) degree or more cams and the appropriate intakes, heads and exhausts are best suited for this technology.

I know you're talking type4 and i've been babbling type 1 but i thought you might find it beneficial. I think the guy we both need to talk to is Jake Raby. He probably knows more about this than anyone. And all his experience and data is type 4.

I hope this helps. And to anyone who reads this, including the people I've quoted or mentioned- I have no experience in this field. All the info i've mentioned is at least 2nd hand and if anyone can correct me, please do.
And Volkaholic-if you should read this, no slight intended. I like what you've done and I'm still waiting to hear from you.

That said, ain't the internet great? Al

[volkaholic1]

No problem, the 1776 in my sons bug is small because I don't want him to have too much power, it is his first car. Jake is very knowledegable about type IV & twin plugs, he & I have talked several times. He has bought several of my twin plug distributors. These things take time, I'm still waiting for my turn in line for dyno time.

[Unkl Ian]

One big problem with dual plugs on Type 4 heads,is figuring
out the angle and location to miss the push rod tubes.

Ideally,I think,the angles would be the same on both cyl,
but the push rods tubes are in different places.

Definitely need a bunch of welding to add material
for the plug to seat against.

[bj]

when i turned over my type 4 head, i wondered how in the hell are you supposed to change plugs and such without fouling the PR tubes too.

it's tight under there.

what i like is that you're supposed to be able to (if done right: disclaimer)run higher compression, less timing, lower grade gas and run cooler while making more power and getting more MPGs (from jake's thread on samba).

very cool stuff. i don't have the finacial backing for any such mod right now, but its cool to see what people can achieve with some money and ingenuity.

bj

[Unkl Ian]

The Harley and BMW guys report similar improvements
in torque and driveability when adding a second plug.

[ALB]

bj-
I think most people use a certain motorcycle spark plug: it's more compact and uses a 10 mm socket.

Funny thing- here in the Vancouver area we have a strong vw street crowd . There are several high 11's and low 12's street bugs that are street driven (one guy who's run 11.90's drives his car to and from work
regurlarly) and one very knowledgable head porter/engine builder. Lots of
knowledge and experience.

But this is outside the box thinking, and I'm amazed at the "this is the norm, stick with what works" attitude that prevails around here. VW performance has come a long way, but it's been by people willing to try something different. You would think that guys that are working at getting the most out of their motors would be interested in any innovation that produces more power. I've stopped mentioning the idea of dual plugs; the
reactions i get range from "why would you want to do that?" to "it doesn't work-everyone knows that." When i ask "how do you know?" no one has
a valid answer.

I guess my point is if you want to try it, then do it. Everything i've read and everyone i've talked to says if you take the plunge and do it you'll be happy with it.For me, it's a possible solution to making my semi hemi heads work properly. What we need here is people trying things and then having an opinion.........

Sorry about the rant to what started off to be the answer to a simple
question, but after talking to a couple of guys Friday night I'm still shaking my head. And the idea of building a REALLY big motor with 101 or 103 mm nickies? Oh gee.....how about another 50 horsepower? "But why would you want to do that?"

[Wally]

I guess my point is if you want to try it, then do it. Everything i've read and everyone i've talked to says if you take the plunge and do it you'll be happy with it.
What we need here is people trying things and then having an opinion.........

Absolutely. Thanks!

[dawie]

Saw a picture of a twinplug BMW motorcycle head. It has 4 valves, with plug in ideal central position,but they added another plug at the side. Doesnt make much theoretical sense in that position,But they claim improved performance, reduced emissions and lower consumption.

[Unkl Ian]

BMW 1200

Another 4 valve example.

[Unkl Ian]

Harley Twin Cam


Norton 500


Motoguzzi

[mikeG15]

I really like the twin plug layout as applied to the Apfelbeck engine, see http://www.apfelbeck.nl/
Mercedes Benz also use the three valve twin plug layout extensively and when I was searching for pictures of these I found this interesting site http://www.eibis.com/eibis/eibiswww/eibisdoc/4007en.htm and http://www.eibis.com/eibis/eibiswww/eibispix/4007.jpg
No doubt people have heard of Feuling , I seem to remember that his name has been mentioned on this site before.
The article mentions the possibility of running a higher CR

[mnsKmobi]

hi bj-

<snip>

and he claims to have talked to
customers of Stan Pabjoy (who does a distributor that looks like volkaholic's- it probably uses the same Nissan cap and rotor) who all rave about it. Stan is a machinist and has been playing with dual ignitions for type 1 motors for several years now, and he claims way more low end and midrange torque. Craig told me about a guy with a type 1 in a bus that now climbs hills in 4th gear that he had to downshift into 3rd before.

<snip>

Al

It's Stan Pobjoy. There was an article on aussieveedubbers a few years back by someone who had a twin plug Pobjoy Type IV engine and was raving about it. I can't find it and I suspect it has been lost or archived.

[ALB]

My apologies to Mr. Pobjoy for the typo.

[bj]

nice pix. this discussion is very thought provoking. too bad there aren't too many folks here that actually have tried them as well.

i have found only one guy that will do dual plugs on a type 4 and that's len hoffman. anyone know of any others? just curious to see who does what.

i would really like to give this a try after i go EDIS with COPs...eventually.

bj

[Wally]

On Engine Plus heads its stock or just a 100 euro option or s/th like that.

The Remmele T1-4 heads have it as an option as well.

And during the existance of the W4 class (unlimited type 4) during the german KäferCup series in the early nineties a few of the guys running there had dual plugs made in their type 4 heads. Most of these engines came from Holzapfel.

So its nothing new, but quit elaborate to make it right and hence very expensive.