Timing issue

[LEB Ben]

Hey fellas...I apparently just can't win. Today on the way home from work, I smelled the gas again and a reeeeeeal bad stutter, which I thought was a carb issue previously stated in another thread. Well, driving to the gf's house, the Bronco seemed like it was on it's death bed...acting like it jumped time...again. Sure enough, I get a light on it, and it was advanced about 25-30* further than I set it. If you recall, about a month ago, I replaced the timing set with a new Comp Cams double roller set...but wasn't thrilled with the quality. I doubt any teeth broke or the chain stretched over the course of a month, but I guess it's possible. So what are the other possibilities? Sheared dizzy gear? But I didn't figure I'd be able to get it resarted if that were the case? Cam bolt backed out? Didn't think it would hold a consistent time then? Any other ideas or suggestions for me? Thanks in advance.

 

[smokey]

If the hold down clamp didn't loosen up and allow the dizzy to turn it might be the shear pin in the shaft. It may have been tight enough that it is just slowly turning.

 

[Mil1ion]

Is it a constant 25*'s out or does it jump around ?

I was going to mention timing on the other thread but remembered you did the TC&G

 

[blacksnapon]

I've had them with a plugged oil pump screen (many of them have a hole for bypass) with dried valve seals. The debris stops the pump gears, shearing/twisting the shaft. This "resistance" can shear a distributor pin.

 

[LEB Ben]

If the hold down clamp didn't loosen up and allow the dizzy to turn it might be the shear pin in the shaft. It may have been tight enough that it is just slowly turning.

The hold down clamp did not loosen up. First thing I checked last night. Got on the daggon distributor with a pipe wrench and couldn't get the thing to move.

Is it a constant 25*'s out or does it jump around ?

I was going to mention timing on the other thread but remembered you did the TC&G

It's a constant 25* off. But I didn't have it running too long that far off...just long enough to see yes, it was out...and then again to show my dad. So probably 10 seconds total each time.

I've had them with a plugged oil pump screen (many of them have a hole for bypass) with dried valve seals. The debris stops the pump gears, shearing/twisting the shaft. This "resistance" can shear a distributor pin.

Good to know. If that's the case, it would just be a matter dropping the pan get a new oil pump and replace the dizzy pin.

 

[Mil1ion]

So you changed the timing gears without removing the dist since it is seized ?

 

[LEB Ben]

So you changed the timing gears without removing the dist since it is seized ?

Huh???? The distributor is fine and does move when I back off the bolt. I thought Randy was suggesting the dizzy bolt wasn't torqued down enough or backed out so that caused movement. I was saying I was thinking the same thing, but last night got on the dizzy as it was with a pipe wrench and got zero movement.

 

[LEB Ben]

It was suggested to me that it's possible the damper spun, sounds like a plausible diagnosis to me, because the damper was pretty trashed. I figure I'll verify TDC tonight or tomorrow. Someone have a suggestion on how to do this without popping the valve cover off?

 

[Ronzi]

The damper being spun wouldnt make it run bad so I would think your timing is off. As for finding top dead center you can remove #1 plug stick a straw or a chop stick in the hole. Turn the motor at the cranshaft and watch for the stick to rise until it starts to go down. You must be on the compression stroke so you will need to make sure air is being pushed out while you watch your stick or straw. You can put your finger over the hole while the crank is being turned to feel for the air.

 

[LEB Ben]

Alright...thanks man. I just really didn't wanna pull that VC off, cuz it'll be a ***** to get it off considering I put that breather on under the AC box. I didn't even think about using a dowel or pipe cleaner down the spark plug...duh.

 

[gsxr1238]

There are a couple of things you can look at without major surgery.As these other folks have said,determine TDC #1,see what your pointer shows for static time in relation to the timing marks on the dampener.Look at the ignition rotor and note the the position of it in the indexing to the #1 on the cap.Do the same with the reluctor indexing on the mag pickup in the distributor.The other tricks are to rock the engine rotation back and forth and follow the distibutor shaft/rotor movement.Should follow exactly along with no lag.You can also pull the fuel pump,and check deflection in the timing chain.

 

[Mil1ion]

Huh???? The distributor is fine and does move when I back off the bolt. I thought Randy was suggesting the dizzy bolt wasn't torqued down enough or backed out so that caused movement. I was saying I was thinking the same thing, but last night got on the dizzy as it was with a pipe wrench and got zero movement.

You misintrepeted what I was getting at.

*I can only comment on what yoiu have stated.

You stated the Dist was seized therefore you didn't remove it when you changed timing gears and being able to verify it wasn't worn out.

I keep telling people about a product called Corr-Block that keeps dizzys from seizing.

A slipped dampner will only show a different timing value when a light is shown on it, they don't change the mechanics inside the engine except for internal balance of the crank.

Fuel blow back through the carb horn is classic timing belt/chain issues

 

[LEB Ben]

Gotcha...sorry for a lack of clarity. I didn't mean the dizzy was seized, just that in it's current state (clamped down), there was no rotation from the dizzy. If I backed off the clamp, the dizzy moves freely as it should.

The reason I thought a spun damper might be an issue was because I didn't know how they were weighted/balanced and if that would cause any issues.


Anyway, the rain has appeared to stop today, so I'll get a chance at taking a better look. I'm really thinking I'm gonna find a sheared distributor gear pin. At which point is just a matter of replacing the gear and pin, right? And checking for shaft damage? And drop the pan and oil pump to get out any debris.

 

[Mil1ion]

Correct on the sheared pin.

IIRC, Externally balanced engines have weights on the Harmonic Balancer, flywheel or flexplate

If the impregnanted rubber in them breaks down and causes a shift. you're in for some weird stuff happening

 

[LEB Ben]

Pulled the distributor out, not any visible damage that I can make out. I'll post pics later tonight in case I overlooked something.

 

[LEB Ben]

TDC lined up just fine and Here's the distributor...everything looks fine to me, unless I'm missing something:

So what's my next course of action? Pull the nose off and check to see if the cam bolt backed out or if something did happen to the cam gear?




.

 

[Mil1ion]

Did you remove the pin to verify ?

 

[LEB Ben]

Did you remove the pin to verify ?

Nope...sure didn't. I suppose that woulda been helpful, huh? Does it just tap out with a dowel or something?

 

[smokey]

Yep they just tap out with a small punch.
Many times they look fine then when you go to tap it out, it will not budge because it has turned on the shaft and the holes are not lined up.
When you tap it out you don't have to completely remove it just a little over half way to verify that it is not sheared off.
When replacing the pin a bit of locktite or nail polish to secure the pin is a good idea.

 

[LEB Ben]

Thanks Randy...