convert load-o-matic carburetor?
- Thread starter edgewood bronco
- Start date
edgewood bronco
Well-known member
Sounds like I should pick up a bit, tap, and three plugs.
X2 
Sorry, but this really doesn't fix the Load-o-matic problem of being a poor performance distributor. That mod gets ported vacuum to the distributor, but the complete advance operation is still flawed in a couple of ways, even though the engine will run acceptably.
First, with manifold vacuum, at idle the distributor will be delivering full maximum advance. At 3000rpm that needs to be about 32-34 degrees BTDC, but when you drop back to idle speed that advance is still there. The engine will likely not idle well with 30+degrees of ignition advance.
So, if you pull the timing back to a point where the engine is idling nicely, around 20-22 degrees, your timing is now 10-12 degrees retarded at higher speeds because at cruise or light throttle you won't have the same full vacuum you had at idle. Even is the idle works out and you can run that much advance at idle speeds, you still run short of advance at higher speeds because the manifold vacuum will not be as high as the original venturi vacuum would have been.
Compounding that, if you set the idle to that amount of advance, the first thing that happens when you tip into the throttle is, all your advance disappears as the engine is loaded. The result is a bog or hesitation off-idle.
Manifold vacuum isn't the solution for the poor old load-o, but neither is ported. Introducing ported vacuum to a load-o-matic might mask the idle, but still puts you out of range at higher speeds and differing loads.
First, with manifold vacuum, at idle the distributor will be delivering full maximum advance. At 3000rpm that needs to be about 32-34 degrees BTDC, but when you drop back to idle speed that advance is still there. The engine will likely not idle well with 30+degrees of ignition advance.
So, if you pull the timing back to a point where the engine is idling nicely, around 20-22 degrees, your timing is now 10-12 degrees retarded at higher speeds because at cruise or light throttle you won't have the same full vacuum you had at idle. Even is the idle works out and you can run that much advance at idle speeds, you still run short of advance at higher speeds because the manifold vacuum will not be as high as the original venturi vacuum would have been.
Compounding that, if you set the idle to that amount of advance, the first thing that happens when you tip into the throttle is, all your advance disappears as the engine is loaded. The result is a bog or hesitation off-idle.
Manifold vacuum isn't the solution for the poor old load-o, but neither is ported. Introducing ported vacuum to a load-o-matic might mask the idle, but still puts you out of range at higher speeds and differing loads.
The Mod has nothing to do with a Loadamatic Dist , its a modification for getting a ported source on a loadamatic style carb , so you have dont have to get a different carb , perhaps you missed that
Thanks FSD. I saw that but I wasn't clear in my explanation, though.
I responded for anyone thinking that this was going to fix their early distributor issues.
I responded for anyone thinking that this was going to fix their early distributor issues.
Yep your right wont fix those crappy dists , its all good 
edgewood bronco
Well-known member
Just to clarify: It does change a carb that was originally set up for a load o matic distributor to one with ported vacuum that is compatible with non load-o-matic distributors, like the DSII?
It will get you ported vacuum.
edgewood bronco":2ezfkn3a said:
Yes as posted it gets you Ported Vacuum Source , and What I recommend for all my Dist Customers
An other option is change the location of the screw in plugs & you have manifold vacuum.
Not recommended for most stock applications, but if your mechanical is curved it is an option for vacuum chambers with a short vacuum advance slot.
Not recommended for most stock applications, but if your mechanical is curved it is an option for vacuum chambers with a short vacuum advance slot.
