I HAVE SUCCESSFULLY CRACKED THE DISTRIBUTOR RE-CURVE CODE!
I think it is common knowledge that desmogging an FJ60 and recurving the distributor go hand in hand. The distributor was set up to optimize performance based on a vehicle with the emissions equipment in place. Once all that stuff is removed the distributor provides too much advance and the advance comes in before you really need it and runs out when it is needed the most. Simply leaving the distributor and timing alone will, in most cases, cause pre-ignition or pinging when the truck is under load. There are a couple of band-aid fixes that will allow you to drive the truck but the results are far from optimal. One fix is to reduce the initial timing to the point that the pre-ignition goes away. This method can cause hard starts and stumbly idle and the truck will feel sluggish and under powered. The other band-aid fix is to leave the initial timing alone and run the truck with the primary advance from the carb connected to the secondary port on the distributor. The second method cured my pinging and allowed me to drive my truck for several months issue-free. It still felt sluggish though and I started to think hard about a dizzy recurve.
There is a vendor on this site who recurves dizzys, rebuilds carbs and sells de-smog components. He does excellent work. I've used him before and I always recommend him to others. I have a trip coming up and I wanted to get the Turdle ready. The vendor was not responding to my emails so I decided to go it alone using information gleaned from MUD. Here's what I did:
Remove the plug wires/vent hose from the distributor cap. Unclip the electrical connector on the side of the dizzy. Remove the cap. Take pics and mark the location of the rotor button in relationship to the engine (mine was pointing directly at the #1 wire position on the cap). Mark the position of the distributor housing. I used a dot of red paint on the distributor and marked a dot on the engine block directly behind. This is not super critical. You do want it close so that the truck will actually start once the distributor goes back in. You will tweak the timing later. Remove the hold-down bolt and pull the dizzy out. With the dizzy now on the work bench, gently remove the plastic cover over the electronic trigger. Remove the two screws that hold the trigger in place (consult the FSM when you re-install to set the gap properly). Remove the vacuum advance clip. Pop the advance rod off of the pin. Remove the vacuum advance hold-down screw from the side of the distributor. Gently wiggle and remove the vacuum advance canister from the distributor. Remove the two screws and the hold-down tabs that locate the advance mechanism. Pop out the vacuum advance mechanism to access the springs, weights and stop pin.
The first issue with the FJ60 distributor is the common problem of the advance stop pin bushing. Inside the dizzy is a pin that keeps the advance in check. Mr. T used a little plastic bushing on this pin. The bushings always crack and fall off leaving only the thin pin to limit the advance. The thickness of this little bushing equates to 3-4 degrees of advance so if your bushing is gone (it probably is) your distributor is advancing more than it should. To remedy this issue I found a replacement aluminum bushing at Lowes for 78 cents.
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The aluminum bushing just barely fits over the distributor pin. I drilled the bushing out just a hair and tapped it over the pin. It holds nice and tight and should provide years of service.
The second issue with the FJ60 distributor is the advance springs. The primary advance spring is soft and thin and the secondary advance spring is thick and quite rigid. They work fine on a truck with the emissions intact but being de-smogged, I knew I needed something different. I picked up an MSD recurve kit (PN 8464) and used the springs in that kit. The kit was $16 at Pep Boys.
View attachment 1279400 The kit comes with a pair of hard, medium and soft springs. I replaced Mr. T's primary spring with the blue (medium) spring from the MSD kit and Mr. T's secondary spring was replaced with the silver (light) spring from the MSD kit. Here is a pic of the factory springs next to the springs that replaced them.
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Once the MSD springs were installed I reassembled the dizzy and re-installed it. I re-installed the vacuum lines with primary to primary and secondary to secondary as they were intended. I played around with the timing and I found that this set-up likes more initial advance than the original set-up. The timing light I have is a cheapo so I don't know my exact setting but it has to be around 15-17 degrees advanced. The BB is down below the sight window about 1/4". It seems like a lot of advance but the truck starts right up and runs great. I drove the truck hard with several pulls all the way up to redline. The truck pulls much stronger throughout the RPM range. Overall the truck just feels peppy. There was no pinging whatsoever and the advance curve seems very linear. My butt meter tells me I have a new truck now! I know I don't but the drivability is night and day compared to before. I will continue to drive the truck and tweak things as needed but for now I am very happy with my set-up.
I am sure that a professional recurve would improve even more on what I have done here but for $17 and a couple hours of time this set-up is hard to beat!
