Need some ignition & carb tuning advice / assistance - RDU (Fuquay-Varina)

[Stubby]

Howdy folks.....I posted this in the main 40 series forum, but it was suggested that I post here as well. I'm having some issues getting my freshly built 2F to idle properly, and some ignition timing issues.

Here are my engine specs.
'76 2F Bored +1mm, and head milled to get around 8.5:1 CR
Head modified for SBC valves and springs
Delta Cams KC859 (262 duration) cam (valve lash set at .008 / .012, per phone conversation with Delta)
De-smogged 1978 carb, rebuilt by Jim C.
1979 Toyota electronic dual advance distributor / ignitor (plumbed into ported vacuum fitting on carb).
New OEM Toyota plug wires, cap, and rotor button
Stock 2F intake
3FE cast iron "2 into 1" manifolds

Engine is freshly rebuilt, and only has about an hour of run time on it.
Compression = 150PSI +/- 3 on all 6 cylinders (rings aren't fully broken in just yet).
Have measured valve lift on all cylinders to confirm no flattened cam lobes.
Have checked for vacuum leaks 4 different times, using multiple methods.....none found.
Have confirmed proper float level, and that it doesn't go too high/low during running.
Temporarily using a 30GPH electric "click clack" fuel pump (showing 3.5 PSI at carburetor)

I'm running into two problems.
1. Anything less than 16-18 deg timing at 650-ish RPM, and the engine runs like crap (sounds like dead mis-fire), and will barely stay idling. It smooths out some around 18 deg., and I took it for a drive to check 4th gear WOT @20 MPH....didn't get any pinging. Haven't checked total mechanical and vacuum advance yet. That was one of the things I'm planning to do this weekend.

2. With the "hotter" cam, I'm pulling about 15-18 in HG at 650-750 RPM. At light throttle, just off idle, there is some surging, and if I blip the throttle there is a slight stumble before it revs. Cupping my hand over the air horn a bit improves the idle quality, which indicates lean idle circuit. I tried richening up the idle mixture screw, but it didn't have any affect. Jim C. and I chatted on the phone, and he thinks the lower vacuum signal is pulling less fuel at idle, so he sent me a couple of extra idle jets to try out. Haven't installed them yet....also on the list for this weekend.


With all that being said, I have a few questions for the Mud brain trust....
- Anyone ever have issues with the KC859/262 cam, specifically reduced vacuum at idle, and/or reduced idle quality?
- I know the 2F's like a bit more timing than stock, but is 18 deg BTDC way off in left field?
- Any idea why the misfire / crappy idle is so extreme at closer to stock timing?

- Finally.....and here's the most important question. My 40 isn't road legal yet, so is there anyone local to Raleigh/Durham area who would be willing to take a drive down to Fuquay-Varina and give me some assistance getting this critter dialed in? I can offer cold beer and free pizza!

Hopefully I've given enough information for someone to have some ideas......

Thanks in advance....

 

[GLTHFJ60]

I feel like you've already tapped the mud brain trust. You've talked to Jim C on the phone. What more could we do?

From my perspective the timing is fine. Run as much advance as you can without pinging.

 

[Stubby]

I'm really looking for another set of eyes/ears, from someone who has done this before, as I'm dialing things in.

I know I tend to over analyze things, so if I'm trying to get things too perfect, there would be someone with FJ40 experience there to give me a reality check. I've worked on cars all my life, but the vast majority of that is on 60's / 70's muscle cars. This is my first rodeo with Landcruisers.

 

[roadstr6]

Is the carb idle solenoid connected? Does it click on when you turn the key? Did you use a paper gasket between the carb and the isolator? The idle solenoid provides your idle fuel. If not working properly, you can adjust the mixture to the point that the carb will suck fuel around the idle circuit. It will run that way, but it won't run happy. Make sure your idle solenoid is functioning. With regard to the paper gasket question...I made the mistake once of using a paper gasket (it is not needed and the isolator has its own bonded gasket) and the edge of the gasket interfered with the operation of the carb secondary butterfly, essentially holding it open just a hair. In that scenario the truck idled high, the exhaust was smelly and gassy and the carb did not respond to any adjustments. Check these two things...Idle solenoid and carb gasket, and move forward from there.

Best I can do. Good luck!

 

[Stubby]

Is the carb idle solenoid connected? Does it click on when you turn the key?

Yes, and yes. It's the one wire version, and clicks with key power. Jim C. mentioned that the holes on the tip of the plunger on aftermarket ones can be sized incorrectly, which will result in poor idle as well. I don't know if the one on mine is OEM Japanese, or a China special. If other diagnostics prove fruitless, I was going to get a new one from CityRacer.

Did you use a paper gasket between the carb and the isolator?

Yes. My heat shield was broken in half, so I cleaned up the bottom of the spacer and used a paper gasket. I did have an interference with the butterfly, but I caught that before I started the engine after rebuild and trimmed out the part that was hitting.

The idle solenoid provides your idle fuel. If not working properly, you can adjust the mixture to the point that the carb will suck fuel around the idle circuit. It will run that way, but it won't run happy. Make sure your idle solenoid is functioning. With regard to the paper gasket question...I made the mistake once of using a paper gasket (it is not needed and the isolator has its own bonded gasket) and the edge of the gasket interfered with the operation of the carb secondary butterfly, essentially holding it open just a hair. In that scenario the truck idled high, the exhaust was smelly and gassy and the carb did not respond to any adjustments. Check these two things...Idle solenoid and carb gasket, and move forward from there.

Best I can do. Good luck!

Thank you for the advice. If you come up with anything else, please don't hesitate to post it.

 

[roadstr6]

Yes, and yes. It's the one wire version, and clicks with key power. Jim C. mentioned that the holes on the tip of the plunger on aftermarket ones can be sized incorrectly, which will result in poor idle as well. I don't know if the one on mine is OEM Japanese, or a China special. If other diagnostics prove fruitless, I was going to get a new one from CityRacer.

Yes. My heat shield was broken in half, so I cleaned up the bottom of the spacer and used a paper gasket. I did have an interference with the butterfly, but I caught that before I started the engine after rebuild and trimmed out the part that was hitting.


Thank you for the advice. If you come up with anything else, please don't hesitate to post it.

Probably not a source of your current problems, but it should be noted that your truck will run much better with a recurved distributor. It sounds like you're running a desmog carb, so I assume you are desmogged. The advance curve on the stock distributor is set up for smog and advance comes on too soon. You'll get much better performance with a proper JimC desmogged dizzy.

 

[doseman]

Stubby
Did you get your issue resolved?

 

[Stubby]

Stubby
Did you get your issue resolved?

Yep. I spoke with the guys at Moseley Motors, and figured out that the Delta Cam grind that I have is the same one they use for their "hi-performance 2F" package. The owner told me that they have to set idle about 850-900 to get it smooth, otherwise it will do exactly what mine is doing. They also run about 16-18 deg. of initial advance with ported vacuum.

I did find that going from a 0.8 to a 1.0 idle jet helped a bit in colder weather, but it made it too rich now that the weather is warm, so I put the 0.8 back in.