65 240 in my F-100. With great ammounts of research, I am pretty certain that I have a loadomatic type distributor. These have only vacuum advance and you can see the springs mounted on top of the plate in the dizzy. The apparently work with a vacuum that is a mixture of ported vacuum and venturi vacuum, the mix of which is based on the spark control valve. PLEASE CORRECT ME IF I AM WRONG

My reading (Ford shop manual, internet, forums) indiactes that in 65 the 240 had the loadomatic carb and dizzy setup, but the 300 did not. The 300 had a mechanical advance as well as the vacuum and the carb did not have a spark advance valve. According to what I have read, the loadomatic setup was phased out pretty quickly in the 240 and NEVER was used in the 300.

Based on that info, I have set out to buy a dizzy for a 300, which should work fine on my engine. Especially since someone swapped out the autolite 1100 along the way for a newer unit without the spark control valve. I looked up and ordered a dizzy for a 67 300 engine from autozone. NAPA and Rockauto listed the same 2609 part number.

But what arrives? A dizzy INDENTICAL to my old one. No mech advance, and springs above the plate, consistent with loadomatic setup.

There are only three points type dizzys listed. the 2609 seems to be a loadomatic unit, The later (early seventies) unit 2689 has dual vacuum hooks. The 2610 units start showing up in the late 60's, and are listed as THERMACTOR dizzies.

BUT, I have no thermactor, and neither did the 300 I6 in 65. And from what I can garner, the thermactor did NOT interact with the distributor. Can anyone comment? Was there something special about the thermactor that made the dizzy different, or is this just the way that the parts places are designating the difference. It is interesting that the vehicles with thermactor pumps do have the later mechanical/vacuum advance dizzies.

I got a seemingly knowlegeable fellow on the phone at Autozone. When I asked him how it could be that NAPA, Rockauto, all have the same thing, he noted that FORD supplies the basic information to all of them. He was NOT suprised that there might be an error in that old a setup.

So, very specifically -- is a thermactor dizzy somehow special and only for thermactor equiped motors? And, if you know, does the absence of a spark control valve clearly mean that I do NOT have a loadomatic dizzy.

Thanks

cdherman

 

Are you going for the totally stock look?
If not why not grab a dizzy from a 70's 300-6 and get the electronic ignition.
Maybe try the "Inline 6" Forum might find a better answer than mine there......

 

Sparky -- yes, I really want to keep a pretty stock look, thus a duraspark swap is less desirable. I plan to drop an Ignitor II into the dizzy once I have the right one.

 

I think you're gonna have to get a vacuum gauge on that carb. and see how much it's sucking (no pun intended). That will tell you for sure what it's doing.

Thermactor dizzys run late timing to get the mixture to burn more during the exhaust cycle. This assists the air injection to light off any unburned hydrocarbons.

I wouldn't let the dual vacuum advance stop you from getting that dizzy. Just hook up your vacuum line to the outer port and leave the inner port open.

Barry

 

Well, got the 2610 "thermactor" carb today. It does have a mechanical (centrifugal) advance, as well as a vacuum. It has only one vacuum hook up.

It does NOT look like the dizzy that my '65 manual talks about in the manual's dual (mechanical/vacuum) dizzy section. Apparently, the 1965 300 I6 had some sort of adjustable mechanical advance. This dizzy has the more conventional (from what I've read) weights and springs. The vacuum doesn't seem to have any adjustment in it either, though the manual mentions being able to adjust the ammount of advance from the vacuum diaphragm with an allen wrench as well.

Barry -- I have talked to ponycarbs -- an autolite 1100 without a spark advance valve should be sending throttle body vacuum to the dizzy. Or did the guy at ponycarbs have it wrong?

The thermactor smog units did not have a vacuum hose to the dizzy -- the later smog units that replaced the thermactor DID have a second vacuum attachment.

I think this is why the parts houses show three dizzies 1) non-thermactor 2) thermactor 3) dual vacuum advance.

I cretainly do not know for sure, but the 200 cid mustang forum says to ditch the old dizzy and get one with a mechanical advance before upgrading to pertronix. I hope they are right.

 

That's what I would have thought about the carb. Next question is how did it work ok with the loadomatic? It would have delivered way too much vacuum for it, max for the loadomatic is around 7" while a regular advance is more like 15".

I can vouch for the mustang forum, I had a Falcon with a 170 and loadomatic, it's a piece of crap. It works marginally ok with a stock engine but add some engine mods and you can never get the timing where you want it all the time.

Barry

 

Assuming that I have a non-Loadomatic carb (eg no spark advance valve), and a loadomatic dizzy (pretty sure there), then I am supposed to get poor performance.

But actually, things seem to run pretty good, of course, maybe I am easy to please. Idle is set rather high. The fellow that did the work to bring her back to life (15 years in a shed) is an old style mechanic, used to race, and can make ANYTHING run. I KNOW he knows a lot. He perhaps fiddled with the idle and advance until it seemed about as good as he could get. I really need to visit with him. Possible that he can answer all this in a heartbeat. Got to get to him before the cigarettes and diabetes take him away.

I swear -- If I ever get this nailed down, I will write a tech article about it. It is clear that Ford went through a number of dizzys in the 60s and 70s and now the terminology has gotten blurry, as well as the technology behind each.

I do appreciate all your thoughs (Barry esp.) -- this has gotten to be like the Holy Grail for me!!!!!!!!

later.....

 

Hey I'm glad we're able to help some way.

Don't know how bad the performance would be but with your combination it's getting a lot of advance. I remember reading a Ford training manual on the loadomatic and the special carb. to run it, it's really interesting on paper and kind of clever but in real life it wasn't as great. I know I still got it around here somewhere, a lot of stuff is still in boxes. Will let you know if I find it.

Barry