Vacuum advance diaphragm leaking, new dizzy? 2/77 - Stock (1 Viewer)

[FJ40 Jon]

My vacuum advance is leaking and just to replace just the diaphragm will cost ~$100 from SOR (if they have it in stock) plus shipping. I know SOR, CCOT, Trollhole, Marks Offroad all have replacement dizzy options. I am also considering trying to find a FJ60 Dizzy set up, but know I will need the coil / igniter combo, plus swap the side valve cover. Anyone have one? Or can I find a OEM 60 dizzy set up easily?

What are the pros / cons of these different options? Other advice? I have heard people like the Trollhole dizzy.

Thanks so much! Happy Turkey Day! - Jon

 

[LAMBCRUSHER]

if your 77 is the same as my 77 was, the advance is actually a retard- or is it retard on one and advance on the other- you have 2 ports on that thing, right? IIRC, those have 2 ports...but even if it only has one, I'm certain it isn't an advance... if your emissions stuff is still intact, then you should make certain that you get the right type of canister or dizzy, or if you want to run the later diz or AM, you need to desmog...

 

[FJ40 Jon]

The advance only has one port on mine. I think they changed to two later in 77. Either way the diaphragm is rotten in there and needs replaced because won't hold a seal.

Thinking of upgrading to the FJ60 set up vs a Trollhole dizzy.

 

[LAMBCRUSHER]

just make sure that you'r rig is desmogged or that it's operating parameters have it's dizzy advancing instead of retarding. the fj60 dizzy is a vacuum advance/advance dizzy- and you'll need to reroute your vacuum lines from the carb to get it to work right...if you're desmogged, the TH dizzy might be the easiest option as it only has one advance can...I'll check my old dizzy when the sun gets up...might have an intact canister...

 

[FJ40 Jon]

It has all original smog components. For the low altitude version <4000 ft. Only had one port, so I think that single port on the dizzy is an advance. The high alt and later versions had two ports on the dizzy.

Thanks for the info!

 

[GA Architect]

Below is my '77 high altitude dizzy on the left, which I swapped out for Mr. Hole's work of art on the right. Note, my high altitude dizzy had a single vacuum advance port.

FWIW - I had plans on installing an FJ60 large cap dizzy and coil, but the TH Dizzy works just fine. Now my large cap dizzy and coil is boxed on my parts shelf.

 

[Curt]

My 78 had a single advance but i switched it over to a trollhole unit.

 

[FJ40 Jon]

Either of you guys have any problems with running the trollhole dizzy or complaints with it?

 

[Curt]

ran it all summer long not a single issue with the dizzy or timing. I run the timing more advance then stock with the trollhole dizzy though, and some others do as well.

 

[GA Architect]

Either of you guys have any problems with running the trollhole dizzy or complaints with it?

My $.02 - The TH Dizzy is a good product, and Marshall is great to work with. I also have one of his carbs as a back-up, and ran it while Dr. Chenoweth rebuilt mine. No complaints for either product of Marshall's.

 

[LAMBCRUSHER]

All you guys using THC diZs..are you running stock emissions gear? I couldn't find my old dizzy today, maybe tomorrow...

 

[GA Architect]

All you guys using THC diZs..are you running stock emissions gear? I couldn't find my old dizzy today, maybe tomorrow...

Mine is De-smogged, with only two vacuum lines....see below the High Altitude desmog diagram, courtesy of Jim C.

The only difference between my old '77 and the TH dizzy, the '77 is a points distributer and the TH is electronic. Thus, see the below diagram I used for wiring it using my OEM coil. Basically disconnected the igniter and only used the coil and ballast.

This set-up has been working fine for almost a year now, and even survived an engine swap.

 

[JohnnyC]

Vacuum advance repair

Saved my vacuum advance dissy...and a few bucks.

Did you open it up and check the extent of the damage to the diaphragm ?

Good links above

If you post a pic we can tell you if its advance or retard

 

[LAMBCRUSHER]

solid GOLD

 

[FJ40 Jon]

Awesome links! Very ingenious repairs on the diaphragm.

I just decided to order a Trollhole Dizzy and upgrade from points, but will probably repair my old one just as a spare.

Thanks for the help!

 

[edwjmcgrath]

ran it all summer long not a single issue with the dizzy or timing. I run the timing more advance then stock with the trollhole dizzy though, and some others do as well.

A lot of us run with more advance than the FSM specifies, even with a stock dissy.
My theory is that since this truck is meant to run anywhere in the world with almost anything for fuel, the specs are very conservative.
As long as you use reasonable modern gasoline, you can advance the ignition (and get better performance) without risking pre-ignition.