Ok, so I tested my dist vacuum and found the vacuum diaphragm must be shot. The inside is filthy, too. I can’t seem to get the vacuum assembly removed to clean the rest of the dist. Do I have to drill out the brass plug at the back end?
Distributor dissasembly
- Thread starter Ziffdaddy
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- #2
Found the c clip to remove it..too much gunk..
There is usually single screw on the outside of the distributor that is holding the diaphragm in. Maybe the diaphragm is seized?
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- #4
Yeah, there’s a screw, but there’s a tiny c clip inside the dist that holds the shaft. Getting her all cleaned up now..amazing how bad it is in there
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- #5
Damn..vacuum canister is shot. Can I run it without it and just use the mechanical advance? I think it was a vac retard anyway..
The spark from the rotor creates ozone from ambient oxygen. The ozone is a powerful oxidizer. We'll be curious to see the mechanical integrity of the weights, springs, and nylon bushings for the centrifugal advance.
Yes, the vacuum diaphragm (retard) is not necessary. That is, unless you have an emissions goal. I couldn't tell the difference running a vac advance or not on my 2F with a new distributor, it ran the same.
Yes, the vacuum diaphragm (retard) is not necessary. That is, unless you have an emissions goal. I couldn't tell the difference running a vac advance or not on my 2F with a new distributor, it ran the same.
My Delco is straight mechanical advance, I hate the vacuum advance/retard stuff - more stuff to go wrong IMHO
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- #8
Sounds good. I cleaned it out really well and the weights and springs all spin and move nicely…is that movement in spec, ugh…who knows..I’ll try it out
The cam swings on the springs and nylon bushings that can be inspected, cleaned, etc., but the breaker plate spins on ball bearings. All those little bearings were pretty rusted on my original '75 2Fs. I'm sure a drop of oil would fix it, but, I rebuilt the breaker plate with the help of viscous grease, and a clean workspace with a bath towel to keep the fugitive bearings from making it to the floor.
I've heard of people sourcing Nippon Denso vacuum advance mechanisms, and modifying the distributor housing to fit a new advancer, and installing it where the distributor housing held a vacuum retard diaphragm. 2F carbs have the 'port' on the carb base so throttle can control emissions. Generally, folks run a vacuum line from the carb 'port' directly to the vacuum advance unit. However, the wax valve (either original or even a three barb type) for emissions plumbing on the thermostat housing could serve as a vacuum control. An original Toyota or swapped EGR valve and vacuum spark advance controlled by 'ported' vacuum thru positive heat on the thermostat is my goal. Either that or just vacuum spark advance on a cold engine, via either ported vacuum or even manifold vacuum. Getting the temp control into the equation makes sense to me, especially if the truck gets better fuel range from it. I don't think vacuum advance for both summer and cold-start winter driving makes much sense, which is how it is running with the direct line from carb to distributor. An option is bumping up the static timing, it would probably run better on a cold engine, and then cut-out just the (hot engine) ported spark advance? I'm sold on the idea of EGR for gasoline motors, it is like adding free fuel (added air to compress) and fuel conditioner (combustion-temperature-lowering with a similar amoung of combustion heat) in one package.
I've heard of people sourcing Nippon Denso vacuum advance mechanisms, and modifying the distributor housing to fit a new advancer, and installing it where the distributor housing held a vacuum retard diaphragm. 2F carbs have the 'port' on the carb base so throttle can control emissions. Generally, folks run a vacuum line from the carb 'port' directly to the vacuum advance unit. However, the wax valve (either original or even a three barb type) for emissions plumbing on the thermostat housing could serve as a vacuum control. An original Toyota or swapped EGR valve and vacuum spark advance controlled by 'ported' vacuum thru positive heat on the thermostat is my goal. Either that or just vacuum spark advance on a cold engine, via either ported vacuum or even manifold vacuum. Getting the temp control into the equation makes sense to me, especially if the truck gets better fuel range from it. I don't think vacuum advance for both summer and cold-start winter driving makes much sense, which is how it is running with the direct line from carb to distributor. An option is bumping up the static timing, it would probably run better on a cold engine, and then cut-out just the (hot engine) ported spark advance? I'm sold on the idea of EGR for gasoline motors, it is like adding free fuel (added air to compress) and fuel conditioner (combustion-temperature-lowering with a similar amoung of combustion heat) in one package.
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- #10
Yeah, my plate was pretty stuck..managed to loosen it up and get it spinning freely again. Seems to run pretty well now. I have ported vacuum on my carb, so I'll probably end up with a vac advance unit soon.
Your picture infers a vacuum advance distributor.
The distributor shaft rotates clockwise, your advanced appears to move the plate counter-clockwise, advancing the timing.
The distributor shaft rotates clockwise, your advanced appears to move the plate counter-clockwise, advancing the timing.
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- #12
I’m getting a vac adv dist. I may have accidentally inferred mine was vac adv..it’s retard, which is standard for 76, right? Anyway, vac assembly is toast..
I'm sorry for the confusion above. But, when the vacuum nipple is on the distributor-side of the diaphragm, it is a vacuum retard mechanism, vacuum moves the breaker plate clockwise (retarded timing), so the engine needs to rotate more to fire on a given cylinder. '76 USA distributors was vacuum-retard distributors.
A modified vacuum retard, early 2F distributor, with vacuum advance, is described in post #5
forum.ih8mud.com
Distributor Tech - '75 through '77 Conversion to Electronic Ignition Using Toyota/NipponDenso Parts
This evening I finished upgrading a lightly used 2015 Trollhole electronic distributor using Toyota/NipponDenso parts. I replaced the stationary (breaker) plate with a '78 through '80 2F stationary plate, replaced the electronics with a new Camry (Celica, not Camry - it was late at night when I...
forum.ih8mud.com
firemanj92
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@Ziffdaddy daddy Reach out to @4Cruisers for more help/info or maybe parts too.
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- #16
I managed to trade the vac advance assembly from a crappy Amazon dist onto my stock one. Runs really nice now.
I'd consider the possibility of the Amazon distributor a source for centrifugal weight springs? Mine are fine, but rusted. I've never seen one, until you mentioned it.
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- #18
Definitely keeping the Amazon unit for parts. I did look at the springs and weights..they all looked and behaved very much the same so I left my existing ones in for now. Nice having the extra parts, though..
