The Ford Barn

Ol' Ron · 01-10-2016, 02:55 PM

Ignition requirements

We've been discussing the building of our Flathead engines from stock to blown. And the tuning requirements of these many different engines are different and confusing. I think an explication of what necessary and why, would make it easier for those wanting to get the best bang for the buck. I have received many Emails and PM's lately asking me for advice. One such person asked, Why should he spend 75 dollars on a new set of $625 heads just to take .020" off of them? Good question.
OK, First, there is only one commercially available distributor on the market that meets ALL the requirements of our daily driver and a trip to Bville, that's the 49-53 MSD unit. I know that may create an argument in some circles. Why?? Well it's the only distributor where you can adjust the mechanical and Vacuum advance to any desired curve. Name another? There isn't one. Lucky we have the SBC distributor which the MSD unit copied down to the last detail. Several of the members here on the barn will rebuild these to any configuration you desire. You can't get that with any other distributor at any price. And they do fit 48 and earlier engines, but don't look right, unfortunately, if you want the best system for your engine this is it. now for the purest the 11A works very well and come close to meeting your needs.
Now just what does the engine need? Well the combustion chamber determines that. The combustion chamber determines the Compression ratio, which determines the volume of the chamber, and the volume determines the area. By milling the heads for a TIGHT fit between the piston and head we in effect shorten the flame front and increase turbulence at a time just before the spark plug fires.
WE also have a carburetor in this equation to deal with. It provides the power to run the engine under heavy load and economy driving down de road. It does this by having the main jets adjusted for a lean mixture and a power valve for those times we need all the power the engine can produce. Some carbs do this better than others.
Now how does the distributor do all this? Well depending on the engines needs it offers a controlled mechanical l advance based on engine RPM. And the Vacuum advance determine the amount of advance under load.
Now if your AF (air fuel) is correct for these conditions, you have an inexpensive engine management system, 6 or 12 volts. well lets see what happens now. Happy New Year..

01-10-2016, 02:55 PM	#1
Ol' Ron Senior Member Join Date: May 2010 Location: Chester Vt Posts: 8,985	Ignition requirements Ignition requirements We've been discussing the building of our Flathead engines from stock to blown. And the tuning requirements of these many different engines are different and confusing. I think an explication of what necessary and why, would make it easier for those wanting to get the best bang for the buck. I have received many Emails and PM's lately asking me for advice. One such person asked, Why should he spend 75 dollars on a new set of $625 heads just to take .020" off of them? Good question. OK, First, there is only one commercially available distributor on the market that meets ALL the requirements of our daily driver and a trip to Bville, that's the 49-53 MSD unit. I know that may create an argument in some circles. Why?? Well it's the only distributor where you can adjust the mechanical and Vacuum advance to any desired curve. Name another? There isn't one. Lucky we have the SBC distributor which the MSD unit copied down to the last detail. Several of the members here on the barn will rebuild these to any configuration you desire. You can't get that with any other distributor at any price. And they do fit 48 and earlier engines, but don't look right, unfortunately, if you want the best system for your engine this is it. now for the purest the 11A works very well and come close to meeting your needs. Now just what does the engine need? Well the combustion chamber determines that. The combustion chamber determines the Compression ratio, which determines the volume of the chamber, and the volume determines the area. By milling the heads for a TIGHT fit between the piston and head we in effect shorten the flame front and increase turbulence at a time just before the spark plug fires. WE also have a carburetor in this equation to deal with. It provides the power to run the engine under heavy load and economy driving down de road. It does this by having the main jets adjusted for a lean mixture and a power valve for those times we need all the power the engine can produce. Some carbs do this better than others. Now how does the distributor do all this? Well depending on the engines needs it offers a controlled mechanical l advance based on engine RPM. And the Vacuum advance determine the amount of advance under load. Now if your AF (air fuel) is correct for these conditions, you have an inexpensive engine management system, 6 or 12 volts. well lets see what happens now. Happy New Year..