Page 1 of 1

Aerovee twin plug 044?

Posted: Sun Feb 11, 2018 6:57 pm
by skipnsb
For a street car: Does anyone have information on the Aerovee normally aspirated engine kit? It is a Type 1 for experimental aircraft, 92bore 82 stroke, with twin plugged 044 heads. I think it is tuned for about 3000 rpm. Would these heads be of interest in building a performance engine? As a low rpm engine I doubt there was any porting but I have not seen them yet.

Anyone know anything about the engine/crank/head/rods parts used in the kit? Obviously the carb will be changed. Thanks in advance.


Re: Aerovee twin plug 044?

Posted: Sun Feb 11, 2018 10:43 pm
by Chip Birks
If you want twin plug, contact MOFOCO, pretty sure they'll do it to any set of heads. Saves you from having to pay for airplane parts.

Re: Aerovee twin plug 044?

Posted: Mon Feb 12, 2018 6:12 am
by petew
I looked into this a while back. Here's a kit from a forum member...


I had a long conversation with my local car guru/mechanic. His basic verdict was this. On most motors it's a waste of time and energy. A hot, fat spark will get you to the same spot.

The only place where you'd REALLY want them is if you're running really big pistons in inefficient chambers. I guess Harley's and top fuelers are a good examples of that. Then the two plugs can give you a better, more even flame front. But again, it only really helps if the chamber/head has been designed for it (Eg. Alfa Romeo twin spark motors). If not, it can lead to weird flame fronts, turbulence and less power. Airplanes only run them for redundancy (I suspect Porsche race cars were similar). As for the emissions angle, a wasted spark system will do almost the same, without more distributors and coils to run them. Ie. more things to go wrong.

However, a few guys have done them over here and swear by it. Still, none of them posted before and after dyno charts. And I can't think of one modern production engine that still uses them. Alfa stopped in 2009. What does that tell you? ;)

P.s. and we haven't even started talking about the timing/location of the second plug. Apparently that's an element of things too.

Re: Aerovee twin plug 044?

Posted: Mon Feb 12, 2018 5:31 pm
by FJCamper
The Porsche (Carrera Spyder) Type 547 engines had dual distributors and two plugs per cylinder were for redundancy. There were two knobs on the dash to run one or both ignition systems.

The Spyders also had dual electric fuel pumps. All this contributed to endurance racing wins.

Re: Aerovee twin plug 044?

Posted: Mon Feb 12, 2018 7:07 pm
by petew
A part of me is still attracted to the idea. But not with distributors. With a crank and/or cam trigger and ECU, it would be much easier. With the right ECU, you could experiment with a slight advance/retard on the second spark plug to see if it helped.

Re: Aerovee twin plug 044?

Posted: Thu May 03, 2018 6:51 pm
by onwardtothestars
The point on an aircraft is redundancy. Nothing to do with performance

Re: Aerovee twin plug 044?

Posted: Fri May 04, 2018 8:13 pm
by Jadewombat
Do a search on the engine management forum here for twin plugs, it's been done a few times over there.

Re: Aerovee twin plug 044?

Posted: Sat May 26, 2018 3:32 pm
by buildabiggerboxer
Adds weight and complexity...But.... as an aside, i had a refusal on a pair of CARRERA 4 cam motors in the 70s, a 2ltr and a 1600, i turned them down!!!
they were no lightweights as id handled them both and saw their power within reach of T1 motors of the day, i wont say the asking price of the time,
but i know i should have had them both.. :roll: :oops:

Re: Aerovee twin plug 044?

Posted: Mon Jul 09, 2018 11:32 pm
by hardrada
A Cessna 170 on the tarmac running WOT with one mag working will produce about 50 rpm less than if both mags were working.

Re: Aerovee twin plug 044?

Posted: Sun Jul 15, 2018 5:15 am
by petew
Interesting... serious question though.

Is that because of the....
Head design?
Mag output?
Spark plug output?

I only ask because from what I understand about twin plug setups is they're effective because of all of these things.