Twin plug Heads

F

Flathead46

New member
Hello, Does anybody have an opinion on where the 2nd. plug should be placed, above the piston or next to the stock plug?Just curious. Roger
 
Interesting reading over at the HAMB about a guy who added a second set of plugs directly over the center of the piston.
 
I think placing a plug directly over the center of the piston offers very little in the way of performance or economy. With piston to head clearance down to .050" or less, What does it do?? Very littler there to go bang. The original location was picked to clean the plug during the exhaust stroke. Remember you had to clean or replace your plugs every 5-10K miles. Relocating to the transfer area is the most logical place, using an extended reach plug. IMHO
 
Hello Ron, I just asked about this as I am building aFlathead for my 29A highboy.We are so Lucky to have people who will give their thoughts and Knowledge with out having to make certain hand shake and signs. I like the Flatfire placement, if you can get a flathead to go 300mph. then some thing must be right. I plan to use twin dissys late model Chrysler with retards etc. The engine will have a 4.3/8 stroke with a3.5/16 bore, Arias pistons pop ups billet heads a roller cam using rebuilt late nodel Hydrolics and the cam will be a torque cam short duration with alift of .460 Roger
 
Hydraulic lifters? How you planning on these working, out of interest?
The billet heads? These gonna be two piece heads, if not what you doing about cooling them? What amount of pop up you planning on using?
need to know because I'm a nosey bugger.
Cheers
Martin.
 
This sounds like one heck of build up. I would love to see it and I'm right down the road in West Caldwell.
 
Well in that case you might need all the help you can get. Now if the top plug is in the stock location it will interfere with the exhaust valve, so you might give that some thought. Good luck.
 
scooder said:
Hydraulic lifters? How you planning on these working, out of interest?
The billet heads? These gonna be two piece heads, if not what you doing about cooling them? What amount of pop up you planning on using?
need to know because I'm a nosey bugger.
Cheers
Martin.
Click to expand...

Hard lines in the valley
I’ve seen it done and it looked like a ton of (hard to get to) work.
The lifter bores were bushed down for some small late model ford rollers.
 
Curious, why not use rollers made for a flathead? Crowler makes them. Not cheap, but may get you to where you want to go quicker.
 
we got the crower rollers in our rail,they have 3 seasons on them and they look brand new,and the engine is a lot easier to turn over .
But I have the stock lifters in my road cars,they are soo quite,and long-lasting
Lawrie
 
Some convert the SBC Hyd roller lifters t adjustable (I don;t know how) to reduce costs. Also the dia of the roller is important for the cam grind?? Goinl to Bville???
 
Hello, Sorry about not replyong sooner but I have been croock (sick). First,please accept my most humblr grovel. The lifters are out of a V6 GM motor, they will be converted to a solid lifter as they have to be shortened, a plug will replace the Hydaulic pieces the lifters will require a sleeve in the lifter bore. The gap for clearence will be done as Ford intended by grinding. Yhe valves etc;are timed out from a race car. I seemed to have shifted countries as I live in Australia but what the Hell!!!!!!
I have a set of "Special" heads which are 2 piece and used on race boats. These have been mapped on a computer and will be made on a CNC mill.
The plug location will be set up either as Flat fire is with the 2 plugs near or over the Ex. valve Or as Richardo had it the first plug between the exh. valve and the bore and the second over the exh. valve. As there 10m. plugs and the thickness in the combustion chamber to be worked out, I will include photos soon as at the moment I am waiting for some money that has been left to me. The reason for using the late rollers is that they are very cheap and appear to have little or no wear.ROGER
 
Thanks for reply, both of them. 's gonna be s project to keep you busy for a while or two. Keep us posted. For what it's worth, the spark plug in the stock location does a good job, in my opinion. If I moved it, I would place it over the centre of the transfer area but only far enough to miss the valves. Again my opinion, I don't think you need two plugs with pump gas. If you feel the need for two plugs, do as you have, research the properly fast stuff and see where they ended up putting them. Flatfire for instance.
Good luck.
Martin.
 
Pete (Nutrocker on the HAMB) has recently fabricated a twin plug conversion for his motor. I have had the pleasure of sharing the driving duties at a few hill climb events in the car and can tell you it goes really well on what is a pretty much a stock French flathead. Even if the second set of plugs don't make a difference they sure look great!



Here is a clip of the car in action.
http://www.youtube.com/watch?v=ku7HDD4g50k
 
For what its worth here's my two cents on the twin plug head idea.
As you already know the twin plug idea is great if your interested in a whole lot of work but in my opinion for no added performance gain. I know for a fact one plug positioned correctly will perform extremely well. While the Flatfire flathead designed and built by Dick Landy used twin plugs to run 300 MPH you also need to take into account the relocation of the intake and exhaust ports as well as the extensive changes machined into the flathead block the twin plug idea was but just one part of the puzzle.
The flatheads built since that time which have gone over 300 MPH used but one plug per cylinder. My gas burning blown flathead with one plug has run over 172 MPH in the standing mile the quality of the plug and ignition system is far more important than an additional plug.
Ronnieroadster
 
gavin m said:
Pete (Nutrocker on the HAMB) has recently fabricated a twin plug conversion for his motor. I have had the pleasure of sharing the driving duties at a few hill climb events in the car and can tell you it goes really well on what is a pretty much a stock French flathead. Even if the second set of plugs don't make a difference they sure look great!



Here is a clip of the car in action.
http://www.youtube.com/watch?v=ku7HDD4g50k
Click to expand...


Dang, that's awesome.

Is there another dizzy on the other side firing plugs as well?
 
You must log in or register to reply here.
Back
Top