Would this New larger gap that can create a bigger spark , Be a desired Step or Spec. When installing a
@Racer65
21100-61012 Non USA Vacuum Advance Carb. Due to Its Increased Jet Sizes?
Would this have a Positive Affect At initial start up / base idle / drive-ability or all 3
No positive effect. When cranking, it is hard to get a spark, so adding load to the spark system by increasing the gap is bad. The minimum gap for making full power (~.030" for a naturally aspirated engine) is optimal. Increasing the gap above that has negative consequences, such as:
shorter coil life due to heat
shorter resistance plug wire life due to heat
increased risk of spark leakage due to higher voltage
shorter cap & rotor life due to higher voltage....
I just grabbed this off @Racer65 / CityracerLLC.com It seems Your 1977 is in luck , Also This is really Good Tech Spec. data for USA applications running SMOG equipment still Like Your self
Toyota OEM vacuum advance distributor with points. OEM part # 19100-61180.
Fits the following applications:
- '75 to '77 Land Cruiser FJ40 with 2F engine (see details in technical information section below)
- '81 to '89 Land cruiser FJ60 and FJ62 with carbureted 2F engine
- '90 to '92 non-U.S. Land Cruiser FZJ80 with carbureted 3F engine
- Land Cruiser 70 Series with carbureted 3F engine
Original equipment on:
- '77 Land Cruiser FJ40 with 2F engine
- Non-USA FJ62, 70 and 80 Series with carbureted 3F engine
Technical information:
- For desmogged applications only. Not California smog compliant.
This dissy is indistinguishable from 76.5-77 USA Fed smog dissy. It can be used to replace an old Fed dissy with a bad vac advancer.
- Due to vacuum advance, the distributor requires a vacuum source from the base of the carburetor.
- The commonly available 21100-61012 desmog carburetor comes with the vacuum fitting
- The original '77 carb should already have 2 ported vacuum fittings. One for vacuum advance, and another for EGR
- Original carbs on '75 and '76 do not have vacuum fitting, but can be added during a carb rebuild. Alternatively, these carbs can be swapped for a 21100-61012 desmog carb
The 75-newer 2F carbs have vacuum advance fittings. It's only 1/75-8/75 Cali-spec that have no vac advance fitting.
- This distributor has the advantage of converting '75-'76 from vac retard to advance
- Must use an updated distributor clamp
No, the 75-newer USA 2F dissy already have the updated low-profile dissy clamp.
Do update to the 2F clamp when installing this 2F dissy in a 1F.
- You should use a coil with internal resistor (such as Toyota 90919-02015 or BWD e40), or you can add an external ballast resistor (part # 90919-04027 or aftermarket equivalent)
Coils do not have internal resistors. The dissy does not know or care if the coil is a 6V coil with ballast or a 12V high impedance coil. If a 6V coil is used with no ballast, the coil & points life is shortened. IOW, do not forget the ballast for a coil that was originally spec-ed to use ballast.
- You should bypass the ignitor
No, the ignitor is a good thing that should be maintained. Why bypass a functioning ignitor? (Rhetorical question, no answer needed.) Do remember to disconnect the condenser when connecting to the ignitor.
- Has built-in anti-overrun feature to prevent conditions that may cause the engine to be over-revved, such as downhill coasting
Wow. No, just no. Cutting the spark does not prevent a mechanical overrev due to a forced downshift or coasting down a steep hill. The throttle is already closed, so the engine is getting no air & fuel.
The rev-limiting rotor is there because there is a slight chance that a 3F with it's shorter stroke, significantly lighter rod&piston and revised cam timing could actually overrev when driven by an ignorant 3rd world goat-herder. For reliability it is best to replace the Rube Goldberg rotor with a normal rotor.
In the long run it probably won't make any difference, but I feel better for providing the above info.
If vac canister is good and you like to tinker, you could pull the dissy and clean/inspect the guts. I pulled apart a similar dissy awhile back. Had a bearing plate like yours. Pretty simple to clean the gummed up grease and relube with fresh slick grease. If the shaft doesn’t wobble, you might be ok.
