1981 straight six manual 4x4 project

[Ford F834]

Gary, I should probably replace it just because... it is hard to tell if it’s on/off or not, because it may need to roll start itself after cutting out.

I do notice that depressing the clutch and tapping the throttle seems to help it to come back after a stall, but often it happens so quickly that all I know is it died, then started running again.

This may be a coincidence, but it seems to happen most often on gradual uphill runs, and seems to happen after a brief stop such as buying fuel or grabbing a coffee.

Probably ~not related, but my tach sometimes works sometimes is completely dead, but does not correlate to the stalling.

So... if I go to buy a distributor, what would you recommend? I see remanufactured, new, and new with a built in ignition module. Any brand preference or one to stay away from?

[Gary Lewis]

I don't have any experience with distributor brands.  But if you are replacing the dizzy I'd go for one that is correct for a truck with whatever EGR setup you'll have.  In other words, if you will have EGR then go with the correct one for your truck.  But if you won't, drop back to one that doesn't have EGR.  That way the advance curve will be close to what you need.

As far as with or without a builtin ignition module, one built in would cause you to rewire.  Do you want to do that?  It would be easiest to leave the current module on the fender.  But if your wiring is toast then maybe it would be time to rewire.

But another option is to just replace the pickup in the dizzy rather than the whole dizzy.  You can do that in situ and not even change the timing - although you should check it as it could change it slightly.

[1986F150Six]

Jonathan, you describe the problem as stalling and starving for fuel... what about the sock/filter on the pick-up tube? Maybe under certain conditions [speed/load], sludge blocks the fuel flow???

[Ford F834]

My wiring isn’t too bad... and no, I’m not exactly hoping to re-wire. I just didn’t know if there were some huge advantages to be had by going to a different ignition set up. If no, then I prefer the stock components.

David, I was thinking along the lines of a clogged pick-up... especially since I battled random stalling with my 1966 truck. It drove me insane until I finally found the culprit: a 1.5” square piece of a plastic bag that was sucked half way into the uptake tube inside the tank. That was a hard lesson on how a blockage could behave randomly. This is also why one of my last resorts was going to be dropping the tank and having a look inside. I had not given it a lot of priority, since I have had no issues under high demand circumstances (3rd gear pull up a 18 mile stretch of 6% grade with the camper for instance)... but blockages can be fickle and behave in odd ways. That said, the randomness with long periods of “good behavior” is making me think it’s electrical. Time will tell. This may be the first time I actually miss the old points and condenser ignition...

[Gary Lewis]

The DS-II system is pretty good, so I don't see a big advantage to changing.  I would change out the pickup just for grins since it is about the last bit you've not done.

On the fuel line, you can blow the sock off the pickup be putting air into the line looking back at the tank.

[Ford F834]

Gary Lewis wrote

On the fuel line, you can blow the sock off the pickup be putting air into the line looking back at the tank.

Gary I’m not quite sure what you are saying here... I did blow into the fuel line and heard bubbles come out in the tank. Are you suggesting this forced the screen off and may be causing a problem? It behaved the same before and after blowing into the line...

[1986F150Six]

What Gary had described is what some Ford Technicians used to do. They used enough pressure [with gas cap off!] to literally blow the sock off. They then put a filter inline between the hard line and the fuel pump.

Jonathan, I will give you my distributor which I took off for the NOS one I located [a few months ago]. The one I am offering is the one I have had while driving for all the time we have known each other. It is the one Gary worked on and has been recurved.

[Gary Lewis]

Sorry, had missed that you'd done that.  Assuming you have a filter in the line, like David suggested, all should be well on the fuel line.

As for the dizzy, David's would be a good match, wouldn't it?

[Ford F834]

So if you have a clogged pickup screen... you are supposed to blow all that crap back into the tank along with a dislodged ‘sock’?  after my experience with the plastic bag fragment I think I would take the time to drop the tank and remove the screen manually, or replace it with a new clean screen... but it must work out if that was a standard practice.

David, if you are willing to part with your old distributor I may be interested in it if you will let me pay a fair used price for it. I don’t know how much you have invested in it with the recurve etc., but we can talk about it via email. The one question I have is it DSII or does it have its own module? I will probably have to do something in the interim (maybe change the pick up as Gary suggested) since I must haul water.

[Gary Lewis]

Blowing it all back into the tank doesn't sound like a good approach.  However, it was done frequently.  I'm thinking it was just kicking the can down the road, though.  Surely at some point all of that yuk is going to plug a filter or mess up the carb - if not the pump itself.

So dropping the tank and cleaning things would be the best approach.  But if you don't have the time, and if you don't know that's the problem, then maybe blow air back through the line just to see if that changes the symptoms?

[Ford F834]

Update... after messing with the distributor I drove ~150 local miles with zero stalling problems. As I said before, I didn’t actually change anything, so the problem would no doubt return at some point. Since the distributor was the last thing to be messed with, I am confident that this is where the problem is.

David mailed me his performance distributor on Monday and it arrived today (Wednesday)

When it started to cool off this evening I installed it and set it at 17* BTDC per David’s suggestion since that is where it performed best on his truck. I could tell right away that the truck sounded the best by ear with lots of advance.





I took it for a spin (water haul run) and found that the advance was too much. It would ping pretty bad when I put my foot down even unloaded on flat ground. So after I filled the water tank, I pulled to the side and backed off the timing to 16* maybe 15.5* (eyeballing where there are no marks). The ping disappeared. Even on a slight incline with 2,200 lb load I could mash my foot to the floor and no pinging at all.

Other observations... the engine has always run pretty well, but this is by far the best it has ever been. It has a nice smooth idle, the nagging hesitation when you stab the throttle is gone. If you punch it while driving it will actually lurch the driveline which it never did before. The responsiveness is very noticeable. I can’t really tell how it pulls compared to before, since my water route is fairly flat, but it seems strong through the rpm band and at least ~sounds better in the higher revs.

This is always a funky comparison, to talk about a performance part compared to a bad/failing stock counterpart. All I know is there is a very noticeable improvement with the new distributor beyond just ~not stalling. I am very happy, and would like to send a very special thanks to David/1986F150six for sending the part to me. I have been nervous to drive the truck very far, and I need to bring a load of tools, wood etc., to our new place (which I can now do). I will keep track of the mpg to see if it changes with the different timing curve.

[Gary Lewis]

Congrat's!!!  Not only is the problem probably gone, but the smoothness, performance, and surely the MPG have been increased.  In one fell swoop.  And, now you'll feel more comfortable not just hauling water or lumber and tools, but driving long distances.  

As for David, that's just the kind of guy he is.    

[1986F150Six]

Thanks to both of you.

Jonathan, I just remembered that the vacuum canister has been maxed out in that it was adjusted to where I could just have a hint of pre-ignition with moderate load at partial throttle. Gary can better explain, but after it was adjusted while at the Garagemahal, I continued to make further adjustments with each fill-up. You might be able to back off what I had done and then further advance the static.

I am very happy regarding the performance enhancement for your truck! Thanks for the feedback.

[Ford F834]

Thanks for the info David, I have a bit to learn about the tuning. So far I have just been happy to have it running.

You are also running manifold vacuum correct? I left my line on the Venturi port, but perhaps it will now tolerate more at idle?

Forgive me, I know you told me before, but how did you extend the timing marks to set it beyond what is cast into the timing cover? I was just eyeballing it, but that is a fairly difficult spot to read, especially since the AC compressor sits where you need to have the timing gun. I am starting to see why people remove it if they are not using it.... but this has been a harsh summer and mine goes nowhere 😬



(Photo of the dash in my wife’s car as we drove around Bullhead City... finishing the AC in the ‘81 is on the short list!)

[1986F150Six]

Yes, mine is connected to manifold vacuum.

The timing marks on mine are not difficult to see. They are on the passenger side.

[Ford F834]

Thank you David, perhaps mine is missing a scale then. My damper has two notches in it, but I have been using the marks on the gear cover...

[1986F150Six]

Jonathan,

I went back over notes and I was mistaken [sorry] when I said 17* BTDC. It should have been 14*. At one time, I did have it @ 17*, but had the vacuum advance blocked off.

David

[Gary Lewis]

Jonathan - The port on the carb only goes to something like 11" of vacuum, assuming your carb is like David's.  And 11" isn't enough to pull the vacuum advance on fully, at least the way I think that one is set up.

So, I'd go to manifold vacuum ASAP.  But, then you'll have more advance when cruising, so listen for pinging under part throttle.  And if you have pinging then back off the vacuum advance by turning an allen wrench counter-clockwise (I think) a turn at a time until the pinging stops.

But I wouldn't play with the initial advance to quell the pinging if the engine is starting well with that timing.  Too much initial causes the engine to kick back during starting, but if yours is happy where you have it then I'd leave it and work on the vacuum advance.

A simplistic, but not completely accurate, way of looking at the order of tuning is:

1: Initial advance.  Dial in enough to get the engine to idle well but not enough to kick back in starting.

2: Centrifugal: In your case that's a given as David had that dizzy set up for his truck and that's a fairly close match to yours.  But, what about EGR?  There's a huge difference in the advance curve for with and without EGR, so what do you have?  And, David, was the dizzy set up for EGR?

3: Vacuum: Dial in all the vacuum you can use w/o pinging at part throttle.  Typically the most critical spot is your top gear at low RPM, but check it out to ensure you aren't pinging anywhere.

[1986F150Six]

The distributor was set for no EGR.

[Gary Lewis]

Perfect!  Exhaust gas in the air/fuel mix makes the flame front slow to spread, so the timing has to be advanced a long ways.  But, since they only introduce exhaust gas during high-vacuum situations, like cruising, then they can't dial the extra lead into the centrifugal curve.  So it goes into the vacuum advance curve.

However, if you run a dizzy set up for EGR w/o EGR on the engine, like Big Blue's probably is, you'll have pinging galore under light throttle.  Which explains why I have to pull the vacuum line off the dizzy when towing - until I really give it heavy throttle there's too much vacuum advance and it'll do worse than ping.