Distributor stop pin bushing dimensions

[Lugal]

Off on a tangent now: if this bushing is awol, would it affect getting dizzy to properly time / align to 7* btdc?
Reason for asking is that my 60 is idling at a lower than usual (450-500 rpm) and the dizzy is turned as far as it'll go towards advance....

I'll bet that your distributor is installed off a tooth (like mine was, briefly, on Saturday). I had the exact same symptoms after putting the distributor back in the truck after adding the bushing.

Pull the spark plugs and spin the motor until the timing pin is pointed directly at the TDC mark on the compression stroke. If the rotor isn't pointed directly at the #1 spark plug wire, then you'll need to pull the dizzy, and reinstall it properly. You'll probably have to put a screwdriver down into the block and twist the oil pump a little bit for the dizzy to seat properly.

 

[Slow Left]

Off on a tangent now: if this bushing is awol, would it affect getting dizzy to properly time / align to 7* btdc?
Reason for asking is that my 60 is idling at a lower than usual (450-500 rpm) and the dizzy is turned as far as it'll go towards advance....

Hmm...so, when the stop pin bushing was awol on my dizzy, and I set the based timing to 7* BTDC, then after I installed the stop pin bushing my base timing was at 10* BTDC (having changed nothing else besides installing the stop pin bushing).

The way I interpret that is that without the stop pin bushing, the weights were able to move an additional 3* below the stopping point with the bushing installed.

So it sounds like you've set the base timing so far advanced that the 7* BTDC bb timing mark is moved well below the bottom of the viewing window without the bushing installed. Then if the same logic applies, if you were to install the bushing, then you would be able to rotate the bb back (towards the top of the viewing window) 3* in order to shift the whole ignition advance curve down to the same base position you have it at now without the bushing.

What altitude are you at?

 

[Slow Left]

I'll bet that your distributor is installed off a tooth (like mine was, briefly, on Saturday). I had the exact same symptoms after putting the distributor back in the truck after adding the bushing.

This is also a good possibility...especially if you have recently removed the dizzy to for some reason...

 

[micruz60]

Thanks Lugal, distributor has not been removed... by me anyway. Now the back story: pulled the original engine (serial#888xxx) in 2011, dropped in a 'reman' (thanks Winslow) with unknown mileage, engine serial is 446xxx, probably 1980-81. That was over 12,000 miles ago. Been running pretty solid, and low idle only occurs upon cold startup. After op temps etc are reached idles at spec.... (i bet theres a vacuum leak story lurking)

I am at 6200' asl. @Slow Left , you are right about the bb off the window.
I have not opened the dizzy up or done anything beyond routine idle check and rotation of dizzy. Since the original motor has been 'splattered' bagged and catalogued for a rebuild sometime, I am going to open up that original dizzy to lern mor!

 

[Slow Left]

I am at 6200' asl. @Slow Left , you are right about the bb off the window.
I have not opened the dizzy up or done anything beyond routine idle check and rotation of dizzy. Since the original motor has been 'splattered' bagged and catalogued for a rebuild sometime, I am going to open up that original dizzy to lern mor!

FWIW I installed the stop pin bushing without removing the dizzy from it's slot...

Be sure to gap the signal generator to spec when you reinstall it (see FSM).

I remember reading a thread recently (could have been in the 40 & 55 section) about someone at higher altitudes setting the base timing at something crazy like 20* BTDC...if I find the thread I'll link it here.

If you've got the dizzy turned as far as it can go so that the bb is gone from viewing window, then that is some serious advance. I'm not sure what you should expect to be setting your base timing at at that altitude, but there are many other variables (as you note) like the operation of other systems on the motor...maybe run the trouble shooting on the HAC as per Emissions FSM, too.

The vac advance shouldn't affect idle though, since the 1st vac advance is ported at the carb...but the HAC might be adding max. 6* advance...

I'm not sure what having the base timing so far advanced is compensating for...I don't think it has a causal relationship with a vac leak (unless the vac leak was in the HAC system)...usually to get the engine idle over a vac leak you've got to turn up the carb screws.

You might start with a tune-up (plugs, wires, cap rotor, air filter and tune the carb) and then try to retard the timing as close to 7* BTDC as you can get it.

 

[Slow Left]

After op temps etc are reached idles at spec.... (i bet theres a vacuum leak story lurking)

How are you tuning the carb? Lean drop?

After setting base timing (I'd set this to backed off just from the point where you hear pinging driving up a steep hill)

Try setting the idle speed to 650 rpms.
Then set the idle mixture to point where rpms stop increasing.
Then go back and set idle speed screw to 650 rpms.
Then go back set idle mixture screw to point where rpms stop increasing.
Then go back and set idle speed screw to 650 rpms.
Then go back set idle mixture screw to point where rpms stop increasing.
...until the two screws are at the same point.

Make sense? Is this how you are already tuning the carb?

 

[micruz60]

@Slow Left , yeah , no need to link the thread. I prolly read it. Much appreciated. I've owned two of these 2f beasts, one for close to thirty years and the 60 for fifteen, pretty familiar with tuneups. Valve adjust etc, both rigs are still smogged, and it is eventual that I will desmog... Just a puzzle as to 450-500 rpm off a cold startup, and then when up to op temps, idles fine, warm starts fine. I'm totally guessing that the bushing has anything to do with it. I suspect vacuum / hac issues, will do the fsm checks.

 

[Slow Left]

@Slow Left , yeah , no need to link the thread. I prolly read it. Much appreciated. I've owned two of these 2f beasts, one for close to thirty years and the 60 for fifteen, pretty familiar with tuneups. Valve adjust etc, both rigs are still smogged, and it is eventual that I will desmog... Just a puzzle as to 450-500 rpm off a cold startup, and then when up to op temps, idles fine, warm starts fine. I'm totally guessing that the bushing has anything to do with it. I suspect vacuum / hac issues, will do the fsm checks.

Understood.

My fully smogged rig takes a while to warm up too in the winter. It'll start right up with the choke, but I've got to keep the choke pulled out 1/2 then 1/4 way for a couple minutes until it warms up...if I push the choke in right away after start up, it'll barely idle...more like a wheez than an idle...secretly I suspect a vac leak in a choke diaphragm since if I leave the choke fully closed after start up it'll sputter, but haven't found a way to test yet (putting MiniVac on the diaphragms checks out OK)...

I've been hunting a performance issue (a weak spot in the acceleration band) for some time now...making small (but hopefully accurate) improvements as I sort through it all and continue to learn more how each system works...just bumped up the base timing yesterday from 7* to 10* BTDC (after having rerun the valves), so I'll retune the carb and see where that gets me...

 

[micruz60]

^thats about right for me, pull choke, crank, starts, high idle for 20-30 sec. push to half stop, then defrost, brush scrape if necessary, sooo, 1 - minute then push in choke. Done it like that for years.

What i'm really looking for is the results that Clove had, running up steep highway, and getting +4 mpg...

 

[ducktapeguy]

Forgot to thank you guys for the dimensions. I found a plastic spacer that seemed to be about the right size and got my dizzy installed last year. I was running a comparison with my stock dizzy to look at the differences and thought it might interest some of you. I just remembered this while trying to figure out another problem on my timing.

https://forum.ih8mud.com/threads/ignition-timing-advance.828092/#post-9511107

 

[Michael Hanson]

Hi, Good read , dealing with this now. Mike

 

[deaven]

Alternate replacement pin bushing: cut a small piece of teflon tubing (4mm ID, 6mm OD - Amazon product ASIN B07B8KMNQN), use drill to enlarge ID to ~4.5mm. You can cut the length so that the top of the bushing pops in below the larger radius ridge at the top of the pin.

I calculate for 23* crank angle advance, the pin-to-rotor linear movement needs to be 4.9mm. This is easy to measure with a micrometer, the max will be the gap between pin bushing surface and opposing rotor tang. You can sand the bushing down a bit to adjust.

While I considered making one from brass, this seemed closer to stock and easier to play around with. I'm doing this on a 1985 FJ60, with the big cap "work of art"

 

[Rockiemosley]

I am a bit confused by the above discussion. Do we want 31 or 41 degrees at max advantage, centrifugal and primary vacuum advance combined? Like so with a dial back timing light, set it to 31degrees and twist distributor until the TDC line lines up with pointer? But should it be 31 or 41 degrees?

 

[Rockiemosley]

Could anyone clarify- the vacuum advance is supposed to advance 18 degrees. Is that crank degrees or distributor degrees, which I assume is half of crank degrees?

 

[mattressking]

Perhaps we can rename this thread into a Big Cap distributor info thread? And bring @4Cruisers info here as well

 

[4Cruisers]

Here are the FJ60 and late FJ40 distributor (19100-61102) advance specifications (multiply by two for engine advance):

 

[4Cruisers]

Here is the FJ60 distributor I just finished modifying for my '76 FJ40. I modified it to 1) replace the dual diaphragm vacuum advancer with a new single diaphragm NipponDenso advancer that has a similar vacuum advance curve to the '77 2F distributor and 2) replace the original signal generator with an early '80s Cressida signal generator. With the advancer I used you can adjust the stop to limit the total amount of distributor vacuum advance - I adjusted it to limit advance to about 10 to 11 degrees.

 

[4Cruisers]

Perhaps we can rename this thread into a Big Cap distributor info thread? And bring @4Cruisers info here as well

I used this thread early on to decide on the replacement stop pin bushings for the distributors I've worked on, so nothing new there. I have several distributors ready to test in my '76 FJ40 (the one above, a 19100-60070 from a non-US F engine, a 19100-61021 from a '77 2F engine, and a late version Trollhole distributor with a Cressida signal generator) - will probably tackle this in a few weeks when the weather warms up. I don't have a distributor machine, I'll leave that to the experts like @FJ40Jim.

 

[js0k]

Figured I’d add my experience to this thread, because it helped me out a lot. Still tuning (freshly resealed engine, 70 thou off of head and valves lapped in, fully desmogged) but it runs like a dream. My stop pin bushing was completely gone. An #8x1/4x1/4 aluminum bushing, 92¢ at Home Depot, went right on. Added MSD 8464 springs (because desmog) and functional vac advance from @4Cruisers and am very happy with the performance.

Thanks to whoever discovered this!

 

[Rockiemosley]

Im just putting this bit of information out for the benefit of the Landcruiser community. I recently had the chance to measure the stop pin in a distributor that was rebuilt by a certain guy who’s name you might recognize. The stop pin had a tiny piece of 6mm aluminum tubing, which was crushed on the pin to a thickness of 4.7mm. The thickness of this spacer dictates total advance travel. The springs were custom and the tension on the springs had been adjusted so a bit hard to reverse engineer that part. As a starting place on springs, if you aren’t sending it out for a professional recurve, you might try the lighter of the 2 stock springs along with the lightest spring from one of those HEI kits.