I just replaced the timing chain in my 1972 F100 with a 360 fe engine because it was starting to jump. It was the original timing chain so it had a lot of slop in it. The timing marks on the new one did not line up exactly but it was super close. I tried moving the chain/gear a tooth in each direction to get the timing marks to line up but that only made it further off so I got it as close as possible and buttoned everything back up. After putting the timing cover back on I noticed the pointer on the timing cover that is used to set the timing was at 4 degrees after top dead center when it should have still been at 0 degrees since I had not moved the engine/car since setting it to 0 degrees to change the timing chain. I thought it may have been because the chain just wasn't loaded/ tensioned in the right direction and once it was it would line up again. After I put it all back together it ran just like before for a day and then the next day the timing jumped. I reset the timing again and it worked for a day but now it has jumped twice in one day. I'm not sure if I have multiple issues at once or if I did something wrong when replacing the timing chain which is causing me new issues or if it's a distributor problem or what. I know the distributor bolt is tight and that it's not slipping or moving because that was my first thought. I'm not sure what to try/ look at next.

 

I'm guessing you had the nylon tooth cam gear since I've never seen a chain on a metal cam gear get loose enough to jump a tooth. Since all FE's use basically the same timing sets the marks should have lined up. But if the timing set wasn't made correctly, being off by 1 degree or less won't affect anything enough to notice.
Did you check the harmonic balancer to make sure it hasn't slipped. Also, you need to pull the distributor and check the roll pin in the gear it is possible it could have sheared. Those gears are pressed on then drilled for the pin. That distributor gear is driving the oil pump, so it is under a lot of load.
Also, if you had the nylon cam gear and it was missing teeth you need to pull the pan and get that stuff out before it ends up in the oil pump.

 

I have almost the same question as the previous responder: Did you replace just the chain, or did you replace the entire timing set? And if the latter, what brand did you use?

Without this info, any response I could give would be almost meaningless.

 

Yes, it was a nylon gear. I don't think the harmonic balancer has slipped because every time I reset the timing, I use it and it runs how it should. I only know the timing is off because it will jump and start to run rough or shift hard. I checked the distributor and it didn't seem to have sheared nor did it have any play in the gear or top end with the rotor. Both the gear on the distributor and what I can see of the gear on the camshaft seem to be in good condition. No signs of wearing or rounding on the teeth. The jumping issue does seem to be getting worse. It seems to be jumping when starting to stopping. Today the timing jumped enough to where it would not run without completely moving the distributor.

 

I replaced the entire timing chain and gears. Both gears and the chain. The brand was Cloyes and it came from the local NAPA.

 

I think your problem is distributor related. Remove the distributor cap and turn the rotor counterclockwise it should move at least 1/8 inch and snap back to its original position when you release it. If it doesn't then there may be broken springs in the centrifugal advance.

 

I checked that and the rotor has 1/4 inch or more of play but it does snap back into place. If I can isolate it as being a distributor problem then I am fine with just buying a new one, it still has the original one from 1972. However I would like to try and figure out the issue, what caused it, or if there is an easier/ cheaper solution.

 

I think I may have misunderstood your initial post, sorry. I first read it as if the timing chain had "jumped" a tooth....

And thank you for expanding on what you installed! Personally, I think highly of Cloyes timing gear sets as well, but I know for a fact that some SB Mopar sets were produced incorrectly in the not so distant past....

Regardless, can you please expand on what you mean by "the timing jumped"? What "jumped"? Did the timing marks move when you put a timing light on the harmonic balancer? That's what I'm assuming now, at least...

Also, how does the engine run? Have you changed the timing (moved the distributor to match the timing marks)? Does it rev up smoothly?

And perhaps most importantly, how old is the harmonic balancer?

(I just went through all of this recently, and I have a hunch....)

Jim

 

What I mean by jumped is that it will run rough so I go and check the timing marks with a timing light and it will usually be off anywhere from 4 degrees to 10 degrees. So yes the timing marks moved. I will set the timing to 12 degrees BTDC and that's where I have run it for 2 years. It had run perfectly there before messing with the timing chain and gears and afterward, when the timing is correct that is still where it likes to run. If I set the timing, drive somewhere, and then try and start it and leave it usually does not run the same. Sometimes the timing is way off and sometimes it's only a little off to where I only notice it when driving at higher speeds. I used to be able to drive 70 mph with no problem and could even get up to 85 mph if I wanted but now it maxes out at 65 mph or 70 mph if I push it (with the ever-changing timing).

When the timing is set correctly it runs perfectly. As long as I don't turn it on and off (giving it the chance to move timing) I could drive for hours without issues. It also ran perfectly before changing the timing set. Yes, when I go and reset the timing I always move the distributor to 12 degrees BTDC and that's where it runs the best. At that timing, it revs, drives, and runs smoothly.

The harmonic balancer is still the original one from 1972, so it's 52 years old. It has a key way so it can't slip or turn on the crankshaft. I also am 99% it's not slipping on the rubber because I still used it to set the timing and the makers line up to where the engine has always run well.

 

Nice response, thank you!

Two things come to mind:

First, if the distributor is still original, or has even one-half as many years on it, chances are good either your vacuum advance is sticking, your mechanical advance is sticking, the bushings have gotten sloppy....See where I'm going with this? Find another FE distributor (from a buddy?), or buy a new (or even used) one. I just had an extremely rare Lucas distributor rebuilt for a '71 Australian Chrysler VG a friend of mine owns, and the "before and after" differences were amazing! Since this is inconsistent in nature, my money is on a sticking advance, and although I've not done this, perhaps there's a way to "lock-out/lock-up" the weights and run 'er w/o any advance, as a test.

Secondly, do you have a TDC tool? If so, double- (and triple-!) check your harmonic balancer! Just because it doesn't have cracks doesn't mean it hasn't slipped. (Ask me how I know this sometime.) And if you don't have one, maybe ask a buddy to loan you one, or maybe your local O'Reilly's/NAPA/Autzone will rent you one. Failing that, you can make one (do a Google search). Or, if you're anywhere near MN, you can always borrow mine. Just drop me a PM. (And I have a few spare FE distributors I could loan you as well.)

Bottom line: If the issue is intermittent, my money is on a sticking advance in the distributor. But if that's new, or tests ""ok", you're going to have to check that TDC as indicated on the balancer is correct.

Good luck!

Jim

 

Actually, now that I think on this a bit, if you find that you do need a TDC tool, but don't have/can't find one, shoot me a PM, as I don't see me needing to use mine for a while.

Jim

 

Are you using ported vacuum advance? Could the ports not be covered sometimes with the choke on? My carburator adjustments had the ports uncovered, so it was getting full manifold vacuum at all times. If it was close on adjustment, maybe the ports are covered sometimes, and not at othertime (choke settings?) I'm no expert, just throwing ideas out there.

 

Yeah, that is a good point. I took the distributor apart to get to the weights and cleaned out the inside. The weights didn't feel like they were sticking however there was a piece of rubber in there that could have been preventing the weights from moving freely. I am not sure where the rubber came from so If you have any idea let me know. I cleaned the inside with brake clean and kroil oil to make sure nothing would stick.

Also when taking the distributor apart I noticed that there were two different springs in there, one being weak and the other one being stronger. I'm not sure if that's how they came originally but it's highly unlikely that someone was in there to mess with them since I am the third owner and the truck sat for a while and only had 70,000 miles when I got it. There were also two markings next to the weights. One was 13L and the other was 18L, I am not sure if that helps at all.

I included the picture below with the markings, two different springs, and the piece of rubber in there that is circled in blue.

 

No, it is usually off by 10 degrees when I go and check it.

 

That piece of rubber is more than enough to interfere with the centrifugal advance weights. The 13L-18L is the amount of advance in camshaft degrees it will advance when the distributor is set in either one of those notches. Yours is in the 18L which will get you 36 degrees at the crank.
If your distributor is marked D0TF-J or K that is the stock setting, they are maximum 38 degrees @ 5100 rpm. That is what those springs control.
The initial timing for either one the above distributors is 6 degrees.
To be honest that is a smog curve and isn't doing you any favors in performance. If it were mine, I would move it into the 13L notch and install a set of lighter performance springs and run 10 degrees initial. Or just buy a distributor for a 1969 360.