Well that certainly doesn't sound right, although I'm not sure what would cause that. My initial thought would be vacuum advance, but you say that's pulled and plugged. My second thought would be timing chain, but you said that's a new double-roller

it doesn't sound like an ignition issue-just a timing issue. Not sure if you mentioned this, but has your newly curved and weighted distributor ever worked correctly?

do you have access to a stock distributor you could swap in?

 

I unfortunately do not have a new dizzy I could swap in.

At idle, she pulls about 17-18" of vacuum. Little bit of needle vibration, but may just be a crappy gauge. Burns a quart of oil every 700 miles, just like any old car does.

The re-curved dizzy was done after I did the timing chain. Honestly the only reason I re-curved it at this point was because the new timing chain didn't change the "butt dyno" feel of the truck at all, despite the old ole being stretched badly and about to shed its original nylon teeth.

Next time the weather is decent, I will check the compression, check and re-gap all the plugs, and check the firing order. I am going to leave the dizzy on the 15L slot to alow for more advance inside the dizzy and run a lower intial advance and see where that gets me. I will set the carb up as a bone stock 1405 also. Check voltage at the coil. Check the air gap for the stator and pick up coil (should be .007"). When all is said and done, timing should be set to 34* total, set to be all in around 3000rpms. Will try some WOT passes and semi spirited driving to see how she responds without vacuum advance.

Any other suggestions to check? Open to literally anything at this point. My head hurts from banging it on the wall and Im sure the neghbrs and giflfriend are tired of hearing me yell at this truck as if it's Christine in truck form.

 

The highish vacuum with a slight needle flutter indicates something like worn rings, but that would not be the cause of the sluggish engine.

When setting the timing curve, did you block off vacuum advance and measure the timing at 500rpm intervals ?
If no, do it.
If yes, and the timing curve was linear (if plotted on a graph that is), it indicates that the mechanical advance is ok.

The drop in ignition timing just off idle could be sticking advance springs/weights.

Is the earthing from the battery to block and engine etc in perfect condition ?

Is the ignition wiring in perfect condition ?

Is the earth strap inside the dizzy in perfect condition ?

Bad earthing in the ignition circuit can cause a surprising amount of power loss.

What coil and dizzy is fitted ?

Depending on what is fitted, the OE resistor wire may not be needed.

If not needed, but fitted, there will be power loss due to higher resistance than needed.

I hope that makes sense.

 

It definately sounds carb related but also very possible it is ignition, when you give it full throttle the firing voltage requirement at the plug jumps up a large amount due to increased cylinder pressure.A quick easy way to tell is pull your plugs and regap to .025 then take a test run if it it improves you need more spark.If not its the carb, the engine itself and timing sound like they are in the ball park based on the fact it runs well at part throttle when taking off.

 

Vacuum advance has been blocked off. Have not graphed timing at 500rpm intervals, but that would be a good idea.

I questioned sticking weights as well, even though thw weights move freely by hand.

Ground cable from battery to block is new, sanded down the bolt hole on the block and installed cable.

Ignition wiring has no issues I can see. All ignition components were new as of 2 months ago, because I was trying to cure a sudden shut down on the highway while driving. Turned out to be a bad pick up coil. All ignition components are bone stock pieces.

O'Reilly MasterPro coil
O'Reilly MasterPro brain no with blue grommet
O'Reilly MasterPro cap and rotor
Packard 7mm wires
Motorcraft ASF42C plugs gapped at .045.
Stock dizzy installed from 1977. Still has original tag.

I have never seen a ground strap inside the dizzy, unless the little brass piece used to hold down the pick up coil wiring is the ground you speak of.

Again the spark thrown from the coil is a sharp blue/white color.

Considering replacing the dizzy with a reman and starting from there. When I remove it from the truck and spin the shaft by hand, it has some minor resistance, but I wouldn't exactly jump on it and say it's bad or too much per se.

 

Hi Dave145,

Just to be sure, I meant block off the vacuum advance for timing curve purposes only. Otherwise it must be connected at all times (for fuel efficiency mainly.)

And before I forget, LOL @ Truck form of Christine.

It's been about 6 years since playing with the dizzy, but I recall a tiny metal strap fitting between 2 screws. Not helpful I know.

Draw a graph with RPM and ignition timing, and mark out the timing at 800rpm (assuming that's your idle), 1,000rpm and then 500rpm intervals up to 3,000rpm.

If you're not getting a linear curve, time to look at that 40 year old dizzy under a magnifying glass!

Your all-in timing of +/-34 degrees can come in before 3,000rpm no problem. (or should do.)

For info, I have fitted a 100% brand new MSD dizzy and 100% brand new Pertronix Dizzy, and both had weird timing curves. They were both replaced immediately under warranty. Both the weights and springs seemed perfect to the touch, but obviously were not when fitted and running in the engine.

So even if you do get a ''new'' reman dizzy, take nothing for granted.

Was the engine sluggish prior to fitting the Masterpro etc goodies ?

I'm not familiar at all with the masterpro brain. Could that be a problem, or can it at least be checked and ruled out as a problem ?

If your idle timing now is 14 degrees with vacuum advance disconnected, what is it when the manifold vacuum advance is connected ? (I would expect between 24 and 34, which is fine.)

If you're happy with the wiring and earthing, that can be at least ticked off the list !

 

This motor has always been a turdish disappointment. When I bought it, the carb was misadjusted, plugs were all loose, etc. Talk about sketchy! Yes I do hook up the vacuum advance after timing curve work haha. It's the only way the truck has any amount of power to it which, while I know is incorrect, at least allows me to drive it and tinker with it. With the advance hooked up to manifold vacuum at idle, I have 44 degrees of timing because it fully advances my distributor, which has 30* of timing inside.

I am considering getting a new dizzy just to rule out the old one (though I hate just throwing parts at something). The other governor I have sitting here has a 12L slot on it which would give me 24* centrifugal advance, meaning I could comfortable run anywhere from 8-12* initial and still be in the 34-38* optimal timing window. Next time I have the dizzy opened up I will make sure to clean everything in it with kit gloves and reassemble and lube. Then try again and see. If it's still jumpy I will likely just replace the dizzy because there's nothing else I can do.

may have another delay in progress though. Woke up this AM to snow on the ground. 70 degrees out 3 days ago and now snow and 25 degrees. Okay then.

 

To get rid of that off-idle flat spot try this; hook a vacuum gauge to the spark port on the carb. Open the throttle slightly and note the reading. Adjust the VA so it starts advancing the timing at the same vacuum.

 

I've just read the entire thread again, and in posts 1 and 7, with the same dates, you mentioned 2 different sets of timing !!

Your vacuum advance timing of 30 degrees is way too high (44 less 14). That should give you partial throttle pinging !

You said that you have an adjustable crane vac canister which is turned all the way in.

Once the timing curve is 100%, turn it out until the vacuum advance is 20. (15 may be more suitable, but try 20 initially.)

What you should have is 14 idle + 20 mechanical = 34 ''Total''. Then add 20 vacuum.

If your ''total'' at present is 44, that's also way too high, and you should have pinging at W.O.T.

Reading your posts, your pinging seems to be minimal.

Do the timing curve, regardless of what you have in there, and this will tell you if the dizzy is ok, or if it's tired.

15L's with new springs in should give you a linear curve up to 44 degrees, but, the symptoms you've described sound like the timing is not advancing (something sticking?), and that's why loads of vacuum advance is making the engine appear to run better.

For now, forget about ported vacuum advance !! You can try that later if you really want to.

You actually don't know if the dizzy is working or not, so getting a new one will be a waste of time at this stage.

Don't worry about the snow !! Ask the girlfriend to dress up nice 'n warm,and to hold the revs steady while you check the timing.
Huge bribe might be needed though ! LOL

A high vacuum with slight steady fluctuations is timing , not piston rings or whatever I said.

My team, Ireland, is about to beat France at Rugby, so I'm off to gloat !!

 

Trying to type this stuff at work and on my phone can be hell sometimes I tell ya haha. Currently the truck has the 15L slot engaged, giving me 30* of advance, plus 14* initial. This gives me light to moderate pinging I found when I stomped the gas while rolling.

I didn't want to just toss a new dizzy in yet either. Just another variable to add, only meant it as a last resort sort of deal if mine is kaput.

If I am understanding your last post correctly, I will set the dizzy to the 10L slot and run 14* of initial timing to give me the total of 34*. I will do this after I do the timing curve, to make sure that the dizzy is in fact healthy.

 

First things first, and most importantly, Ireland won the game.
LOL

Ok, great, we're on the same page.
44 degrees total should give a lot of pinging, but yours is moderate. (WOT)
30 degrees vacuum advance should give a lot of pinging too, at part throttle, but yours is minimal.

This suggests that your mechanical(centrifugal) advance is not moving as quickly as it should, and maybe sticking. (or springs are not 'light' enough, or whatever.)
I.E. In effect your timing would be too retarded, which robs power.

Yes, the 15L slots and 14 initial gives 44 total which is too high.

But for now, yes, it will do for checking the timing curve.

You want something +/- like this, which is more or less linear :

RPM Timing

800 14
1000 20
1500 26
2000 32
2500 38
3000 44

If it is way off, there's your problem, and forget about the 10L slots.

If it is similar, fit the 10L slots, and your total will be 10+10+14=34.

Then do the curve again and you should get +/- :

RPM Timing

800 14
1000 18
1500 22
2000 26
2500 30
3000 34

Whatever the outcomes, set the vacuum advance to 20.

Fine tuning the mechanical and vacuum advances can come later.

If the curve is ok, the dizzy is not the problem and it's time to look at the carb/fuelling.

Checking the timing curve is quick 'n easy.

Hmmm. New dizzy might be cheaper than bribing the girlfriend though !! LOL

LOL @ typing at work and on the phone. I hear ya !

Did I mention Ireland won the game ? LOL

 

If all else fails grab a stock points distributor and use that. They are always good for troubleshooting and generally work just fine for daily use, too.


Gotta say that the 34 degree overall timing looks a lot better than 44 degrees... that's a lot of timing for any engine!


- boingk

 

Well, spent the majority of the day on that useless turd and still have nothing. Worse than when I started. Removed the dizzy and cleaned it top to bottom. Set it to the 10L slot while I had it aprt. Installed a yellow and a silver spring into it to hopefully bring all my advance in around 3000rpm, while still sticking with the idea Ford had of using 2 different weight springs. Set my carb to bone stock 1405 specs, checked firing order (it was correct), set timing to 14* and took the timing curve. Curve looked like this:

800: 14
1000: 14
1500: 12
2000: 18
2500: 25
3000: 30
3500: 34

Tuned the carb, got 18" of vacuum out of it at idle. Left the vacuum advance off and plugged. Went out for a drive and it was...worse than my '76 Dart with a slant 6 for performance. WORSE! How could it be worse?? Stomp it to the ground, huge bog, no get up and go. Half way to the floor, slight amount of power, but hey even smallblocks have their glory.

Hooked up the vacuum advance, ya know for ****s and giggles, and...while it improved a bit, still a turd. Can't chirp even one tire. Zero get up and go.

I'm at my wits end with this truck. I have never driven a 460 with so little power. My smallblock 400 in my old '78 F250 had more ***** than this.

Please tell me I did something wrong in the above setup. As much as I don't want to sell it and find another, this thing is honestly one of the biggest bags of crap I've ever seen in terms of performance.

You could TOW this thing faster!

 

That drop in your ignition timing looks like a problem.

The "good" thing about all this is that it's consistent and reliable

Still sounds like a problem in the distributor to me

 

Hats off to you for perseverance. It will eventually pay off !

What didn't you understand about ''leave it as it is'' to do the timing curve ? (Changing springs etc in that OE dizzy is a ball ache!)

Ok, the timing curve indicates a problem at 1,500rpm (which could be causing your acceleration bog), and also indicates that the timing is advancing too slowly.

It's not a bad linear curve, but can be improved.

Lighter springs will make it advance quicker, I.E. Higher advance at each 500rpm intervals.

BUT, I think that the dizzy is tired. I don't know exactly what would make it retard so may degrees at 1500rpms.

The good news is that the timing curve has given you useful feedback.

The bad news is that you went and adjusted the carb at the same time as adjusting the dizzy. Now you don't know exactly what caused the truck to run worse today.

Focus on one thing at a time, and one thing only !!!

Today, in effect, you retarded your timing by 10 degrees by swapping the 15L's to 10L's, and that is probably the power loss you felt.

That said, all of the timing numbers mentioned since the start of this thread are in the ball park, and shouldn't be causing you the crap performance.

18 degrees of vacuum. Was the needle steady or fluctuating ?

Is the engine smooth at idle ?

I don't know the exact detail, but here's an idea :

If the OE dizzy came with points, the points would take 9v when running, and 12v at start up.

An OE resistor wire would be installed to reduce the 12v to 9v when running.

Let's say that wire has 3 ohms resistance. (Purely for illustration)

If the Master Pro Brain replaces the points, what is the minimum ohms for it ?

Let's say it is 2 ohms.

Having a 3 ohm wire will rob the engine of power.

I put an ignitor in my OE dizzy a few years ago, and fitted an MSD blaster coil.

The coil rating is 0.7 ohms and the ignitor stated a minimum of 1.5 ohms.

I fitted an 0.8ohm ballast resistor, with normal wire, and it ran 100%.

But I also fitted a 1.5ohm ballast resistor for pure curiosity. Turd !!

If you understand what I'm getting at, it's a 5 minute job to check it out.

LOL, I couldn't get the OE dizzy to give me a 100% curve, so I gave it away and got a Pertronix dizzy. 'nuf said.

Laterz