On a small cap electronic distributor from 78-79 era, there are two diaphragms. The diaphragm nearest the dist. has a vertical port and the other "outboard" one has a horizontal port. One is vac advance and one is vac retard. Which port is which?
Vac adv port
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When I got mine of similar era, the guy who was helping me said they were both advance. (He is secretary of the TLCA so I took his word for it) This is a quote from a conversation with him "One is normally for the high altitude compensation. You can t both of them and use them both for more advance. Or use one only and fine tune it to your driving style based on which one provides the advance you want. I can't off the top of my head remember which port provides which # of degrees of advance tho.." Hope this helps.
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mano002 said:
There are all kinds of different types. If one port is inboard of the diaphragm (the metal seam ov the vacuum can) then it is going to move the breaker plate the opposite direction as the port outboard of the diaphragm.
If you have checked and one is really advance and one retard, then you have a '78 distributor. '79 began the advance / advance distributor which was part of the high altitude compensation system.
9/'77 - 1/'79 = advance / retard with the retard being the innermost diaphragm as PinHead said above.
1/'79 - 7/'80 = advance / advance. This can be identified by having two rims around the advance module rather than just one. The horizontal port provides about 17 degrees advance and the vertical another 4 degrees.
For more info about adding a small cap electronic distributor to an older FJ see my old post over at Pirate about making the swap. I included more info about hooking up the electricals and the waterproof cap ventilation.
9/'77 - 1/'79 = advance / retard with the retard being the innermost diaphragm as PinHead said above.
1/'79 - 7/'80 = advance / advance. This can be identified by having two rims around the advance module rather than just one. The horizontal port provides about 17 degrees advance and the vertical another 4 degrees.
For more info about adding a small cap electronic distributor to an older FJ see my old post over at Pirate about making the swap. I included more info about hooking up the electricals and the waterproof cap ventilation.
