Bouncing Tach when Cold, and Zap Noises

[OsoMoore]

Originally Posted by wwest

I would suggest disassembling yours first just to be sure it's rebuildable.

How the heck do I get this stupid vacuum advance unit off? All I can find online is "wiggle it" and I've wiggled and jiggled, but its not going anywhere.

[wwest]

Originally Posted by OsoMoore

How the heck do I get this stupid vacuum advance unit off? All I can find online is "wiggle it" and I've wiggled and jiggled, but its not going anywhere.

If I remember correctly there is a snap ring, covered by cotton wadding, inside the hollow shaft that must be removed. Then the screws holding the pickup coil can be removed....

[OsoMoore]

I'll keep tweaking at it. I am soaking the Timer Core (811) overnight and hopefully it will come off easily tonight. I couldn't get it yesterday.

[OsoMoore]

Opened it up! That pin at the bottom is a huge pain. I had to drill it half out before I could drive it out with a punch. Inside there was a lot more filings, and what looks like pieces of a shim. Here are some views of what was inside.

The complete set of bushings, clips, etc. In order so I can reference it later for reassembly.


The bottom, which seemed in pretty decent shape. However the shim that lies on this surface was partially disintegrated. See the picture three pics below. The shaft spins smoothly in this hole, and has no side-to-side play at all.


The shaft's guts. They were super dirty and quite nasty over all. I took it the rest of the way apart and cleaned it with paper towel.


The guts! The bits were scattered throughout, from the vacuum advance to the bottom of the housing. The spacer-thing was between the bottom of the housing and the first thing on the shaft inside it.



Questions!
1) Is this mess possibly the cause of my erratic firing?
2) How should I best clean this out?
3) Does anything expensive look damaged?
4) Should I disassemble the weights and springs? They seemed to move well, but there is junk scattered through the mechanism.

Thanks everyone - this is quite a chore but not as bad as the transmission last summer...

[timmy2]

As long as the body and shaft are not worn you should be ok with new bushings and shims. Contact cleaner is what I used when I did mine.
Removed all the nasty old grease from the weights area.

[OsoMoore]

I'm checking with PartsKlassic to see what they can send me for new inner parts. I'm hoping that the old bushings don't need removal, but we'll see.

[OsoMoore]

Talked to Kurt at PartsKlassic. He's a very helpful guy, spent 20 minutes on the phone with me walking me through parts of the system. Based on where the arcs are jumping, it is probably the coil which is failing. I am planning to replace just the top bushing, as things were generally working smoothly. Along with that, I'll replace shims.

Any ideas on what best to re-lubricate it with? Also, does anyone in the Milwaukee area know of a good shop to remove the old bushing and put in the new one? It would probably need to be reamed as well.

[wwest]

The random sparks were undoubtedly the result of the metal filings closing the magnetic path between the reluctor and the pickup coils armature.

On the other hand the oblong wear of the spacer indicates side play/travel of the dizzy shaft which might close the gap between the reluctor ring and the pickup coil's armature. Look for metal "strike" points on the inside of the reluctor ring and the outside of the pickup coil's armature.

[OsoMoore]

Distributor is cleaned and back together. New shims and so forth. She has no slop and spins smoothly. I hooked it up, in addition to a new coil. However the engine is not starting at all. No sound of combustion. Just the cranking. CDI box is whining.

It was running before, and everything I've done is electrical. So I can probably assume it is a lack of spark. Right now it is 34 degrees out there, but I am thinking I should start at the CDI and start checking things.

I replaced the green wire in the same swath of changes since I previously had it running. I had checked the green wire's conductivity through the new connection, and didn't find any issues.

Things I am thinking about checking:
1) Take off the cap and turn engine to TDC. Make sure distributor rotates and is lined up properly to the mark on the distributor.
2) Put a spark plug on the coil's output wire and check that it is sparking there.
3) Swap back old coil. Maybe new one isn't working right?
4) Pull distributor out again and re-check continuity between green wire end connector and CDI connector.

Any other ideas are appreciated.

[wwest]

2. First.

No spark, check continuity, measure resistance of dizzy PU coil from/at CDI connector.

Spark, then 1.

No start, ????

4/1

[timmy2]

Show us a picture of how the rotor looks at #1 TDC in relation to the mark on the distributor body.
Very easy to be out a tooth. (Ask me how I know)
Leading edge of rotor as it turns counter-clockwise, should be just nearing the mark with dizzy in mid adjustment range at the hold down bolt.

[OsoMoore]

I checked for spark on a plug - No Spark.
Hooked up an old spark plug wire to the coil directly (in place of the coil-to-distributor wire) - No Spark there either.

No spark, check continuity, measure resistance of dizzy PU coil from/at CDI connector.

PU - Pick Up? I'll pull the coil and check these wires next.

As requested, here are pics. I have had the dizzy out a few times before and I'm pretty certain it is aligned just where it was before.

[OsoMoore]

I adjusted the timing bolt after the 3rd picture to make sure the contacts were aligned. Still no success. I'm thinking the pickup may be the issue. I tested the continuity before, right after I did the connector splice. But I haven't tested the whole system since.

[OsoMoore]

I pulled it back out and sure enough, my connection for the new PU wire was bad. Fixed the connector!

However I forgot to put it in TDC before I pulled the dizzy this time. Soooooo 50/50 chance it? Or is there some secret way to know?

[timmy2]

For sure way is to find #1 TDC with #1 plug removed and using a depth gauge (Plastic stick) feel for the correct position when the piston is at it's highest point on compression.
Worked for me when I had to pull the dizzy and then the engine rotated.
Or, 50/50 it...

[OsoMoore]

50/50 did it!

Everything seems to be working great. Ran her around the block a few times (including giving a neighbor kid a rid and "the car talk"). No bouncing tach, no arcing noises.

I can't be sure if it was the coil, the pickup wire, or the messy dizzy. But all of them needed love, and now all of them are happy. So I am happy.

Thanks everyone!

[wwest]

Originally Posted by OsoMoore

Video of the test.

Playing forward.... more

Can physical contact of the alternator rotor with the stator due to "impending" bearing failure cause enough EMI/RFI to "misfire" the CDI? Even with the VR depowered?

That certainly begins to appear to be a possibility...