Chain and Sprokets Replaced/Still Timing Issue

[Girl In Big Truck]

I replaced the timing chain and sprockets. Was needed, never been replaced. All lined up and good. Then started having another timing issue with a random low thump from exhaust. Also had serious trouble getting up hills (not right). First thoughts and response to that was that I may have put the sprockets on 180 off, on the exhaust stroke. But wanted to get some more opinions before taking it all off again. Seems like something is still off and or slipping (Not the chain or distributor, have verified that). Wondering if it is possible that cam could be worn and slipping occasionally? But more likely I put the sprockets on 180 off.

Good example of weirdness is yesterday running perfect! Started this morning, and timing totally off, had to reset distributor (Someone pulling my distributor out in the wee hours of the night?)...

Now this is really weird --> About the above picture: The distributor, re-manufactured, has two blue dots, one on diaphragm, and one on cam gear. When harmonic balancer marks are aligned at TDC, and I align the two blue dots on the distributor when putting it in, it seem in time when running, but as shown in pic, turned all the way to right, and the distributor rotor is 180 off from where rotor should be pointing (towards cylinder eight).

And if asked, yes, all other external parts have been replaced and good that would interfere (plugs, wires, dist, egnit coil, etc, etc....)

 

[Mil1ion]

Somehow you have gone away from natural method.

When one changes timing gears every thing should be lined up..a mark made on the intake where the rotor is pointing. ..a mark made on the intake where the VA is pointing.
Crank turned to TDC watching Intake valve close then turn a little more to TDC.

Then and only then do you pull the distributor.
The timing marks (dots) on gears are pointing toward each other.
Slide off old... Slide on ..new with dots aligned.
Squire a little oil or timing gear lube. ...button up the front cover or insert distributor to original markings ...to turn crank checking for free turning.

Whenever you remove distributor always reset to the original markings before removal..never turn crank unless you are POSITIVE the crank and cam are in the original timed position.

Too many times..people turn the crank with new chain and gears ..forgetting to put them back in the correct position ...the original timed position.
Then when done. ..reinstall distributor to marks made on the intake.
Never trust your memory. .make marks.

If you have messed up the gears and chain install then you have to start from scratch.
It's pretty tough to screw up because the crank gear has to slide over the key.
If you're sure you installed them correctly. .you may be one tooth off with the rotor position.
Put crank back in TDC at end of compression stroke and make sure the rotor points to number one when distributor is seated properly.

 

[Fellro]

The crank turns 2 times per one of the cam, so as far as crank to cam timing goes, you can get away with it being 1/2 off, as it really doesn't matter, the crank is in the same place both times. What does make a difference is the actual tooth to tooth location, which if the marks were straight up but on opposite sides, it is easier to be a little off.

If the motor seemed good, then suddenly changed, it is a bit more intriguing, but if it was not right from the get go, then you are likely a tooth off. To get 180 off while running is not realistically possible, even with a severely loose chain. A tooth or two yes, but a full revolution, no. If the ignition timing was 180 off, you wouldn't get it to run at all, but lots of popping through the carb...

 

[Girl In Big Truck]

Too many times..people turn the crank with new chain and gears ..forgetting to put them back in the correct position ...the original timed position.
Then when done. ..reinstall distributor to marks made on the intake.
Never trust your memory. .make marks.

Unfortunately I had no choice. Forgot to mention the reason I had to change the chain and sprockets was not just to do it, but the chain was so loose it jumped a few teeth while going 60 on the interstate. I was lucky it didn't break.

So I had to turn crank, or may have turned cam, in order to get it back where it was suppose to be (cam and crank sprocket alignment dots).



That was old before I took off, was super loose and had jumped teeth when broke down. Both chain and sprockets were worn down pretty good.

Dots on new sprockets were aligned, but could have been one tooth off and didn't realize it.

 

[LEB Ben]

FYI...this may or may not help you at this point:

http://www.fordtruckfanatics.com/forum/showthread.php?t=13066

 

[Girl In Big Truck]

FYI...this may or may not help you at this point:

http://www.fordtruckfanatics.com/forum/showthread.php?t=13066

Thanks. Yep, I already did all that. That was the easy part. Started fine this morning after resetting distributor again yesterday. Not going to touch anything till it does something weird again. Carburetor set good, and distributor is still like in pic, to far right. I question that, but it is in time, for now.

If it keeps getting out of time every few days, then I'll just have to reset the sprockets, may be a tooth off.

 

[Girl In Big Truck]

Another question I am having that could be an issue is "gear ratio of distributor versus cam". Reason being, I had to get a 1971 ford f350 distributor to match the original. All other parts match for a 1974. Would that make a gradual shift in engine timing? The 1974 distributors have different wiring harness, but I am uncertain if gear ratio is different. If it is, this would explain allot.

Timing got thrown off again last night, but was good for a few trips out. Didn't touch anything during that time. So timing is going out every other day, or about every 10 to 15 miles of driving.

 

[Fellro]

Ratio should be common no matter. I am wondering if somehow the roll pin that hold the distributor gear to the distributor shaft isn't sheared off.

 

[smokey]

That's what I'm thinking also Roger.
Timing just doesn't change either the distributor is loose and rotated or the pin in broke.

 

[Girl In Big Truck]

Or roll pin on upper timing sprocket? (that was another thought), And is there a pin on the cam gear that meets the distributor gear? I swapped the distributor again a couple of days ago, and still going off every few days, reset distributor again earlier tonight, and started right up, in time, and is now to far left... notice in previous picture was to far right...

 

[Fellro]

If your cam gear was getting that far out of whack, you would have likely gotten into some valves. Even though these aren't interference motors, if a valve is wide open when a piston comes up to TDC, they are going to have a meeting that won't end well...

 

[Mil1ion]

Distributors are advanced or retarded ..not left or right

What colour is the grommet on your ignition control module where the wiring enters it?

Brown of blue?

Do you have a timing light?
If so..keep track of timing changes using it.

There is 45* between each spark plug contact on the dist.

If the timing is changing dramatically..you may need to be checking the dist shaft twisting by removing the cap and using a remote starter switch and watching the rotor for constant twist.
I can't think of any safe way to hold it from turning manually.

 

[Mil1ion]

Is the dist... points or electronic ?

 

[Fellro]

Being a 71 distributor, I would expect points... 74 should have been as well, but that is not an "always" as I have seen late build date have the next model year parts show up. That was more a Chrysler thing though.

 

[Girl In Big Truck]

Points, and no ignition control module. Wasn't an ignition control module from the start. Should there be one? Wouldn't explain why I never had this problem before with the same set up.

 

[cbaker65]

It almost dont sound like a timing issue...

 

[kiwi f150]

Have you pulled the distributor yet? - roll pin may be damaged as suggested but also check the balance weights in the distributor ...... maybe there is a difference between ignition curves on the 71 and 73 . I realize i'm posing more questions than answers but if everything mechanical checks out (pretty hard to get it wrong) then i'd say the ignition system has to be where it's at

 

[Fellro]

With it being a new dizzy, you would hope the darn thing isn't sticking, but it would explain a few things... You have to be within a certain range though for it to be running at all.

Now this is really weird --> About the above picture: The distributor, re-manufactured, has two blue dots, one on diaphragm, and one on cam gear. When harmonic balancer marks are aligned at TDC, and I align the two blue dots on the distributor when putting it in, it seem in time when running, but as shown in pic, turned all the way to right, and the distributor rotor is 180 off from where rotor should be pointing (towards cylinder eight).

Let's get back to basics here. Remember how I said the crank makes two full turns per each one turn of the cam? Well, that means the timing mark on the harmonic balancer will align 2 times per one turn of the cam, which then in turn also means that the distributor makes one full revolution per 2 times around on the crank. So that means that there will be two times the mark on the balancer is showing TDC, one when the distributor points at the plug you want to fire, the other time will be halfway through the firing order, which will make the distributor rotor point--- 180 degrees off---. It is possible that you simply are not getting the crank at TDC AND the cam at the point it is ready to fire the #1 cylinder. Common rookie mistake.

 

[Big Jim F150]

The ignition module came out in 75 with the Duraspark II electronic ignition systems.

 

[kiwi f150]

With it being a new dizzy, you would hope the darn thing isn't sticking, but it would explain a few things... You have to be within a certain range though for it to be running at all.



Let's get back to basics here. Remember how I said the crank makes two full turns per each one turn of the cam? Well, that means the timing mark on the harmonic balancer will align 2 times per one turn of the cam, which then in turn also means that the distributor makes one full revolution per 2 times around on the crank. So that means that there will be two times the mark on the balancer is showing TDC, one when the distributor points at the plug you want to fire, the other time will be halfway through the firing order, which will make the distributor rotor point--- 180 degrees off---. It is possible that you simply are not getting the crank at TDC AND the cam at the point it is ready to fire the #1 cylinder. Common rookie mistake.

I'd agree with you there Roger - the bit that was said here in the 1st post sort of confuses the issue (Good example of weirdness is yesterday running perfect! Started this morning, and timing totally off, had to reset distributor (Someone pulling my distributor out in the wee hours of the night?)... ) ..... if it is running fine on an intermittent basis then something has to be loose - i'd really like to have the distributor pulled and the roll pin checked on the gear just to eliminate that for a start.