Excess Rotor Movement?

[Bruce Allert]

I noticed that there is 1/4" - 3/8" movement in my rotor. I put it on TDC via the mark on the flywheel but the rotor was a little more than a 1/16th off at the dizzy. I wondered if there was play in the shaft so I tried to move it. It moved relatively easy from a hair past TDC to clockwise & back. Easier than I'd thought it would. I didn't try moving it from side to side for sloppiness just rotation slop. Is this normal or is the dizzy worn beyond repair? The car was running quite good then developed a miss. It runs great at WOT. Also, I read DD's write up on timing and it looks like the red mark on the fan that he has pitcured is the 27 BTDC. If I time to that on my 73 1.7 EB with EFI it really runs bad. Apparently when I marked the timing mark using the Pelican graphic I think I used the red mark at TDC. If I time to that it runs & idles nice. I gotta recheck it in the morning. I just read various posts about installing the Petronix Ignitor. I'm not sure if I should go with this or get another dizzy. It feels like I'm only running on 3 cylinders until I go to WOT then it smoothes out. Any opinions? or $.02 worth??? bruce

[Dave at Pelican Parts]

The rotor can be moved back and forth. It should be spring-loaded to move back to neutral again, though. When you do that, you're pulling the rotor against the advance mechanism, and the springs push it back to zero.

--DD

[Bruce Allert]

It doesn't spring back. It feels like it is moving through thick molasses. I have to move it back to original position. Does this mean it needs a good cleaning? Dave, How about the red mark on the fan you pictured? Is that supposed to be the 27 BTDC?
bruce

[Zeke]

Yes, it should move and snap right back. Something is gummed up in there. The line on the rim of the distributor is just for reference, it won't be exactly lined up with the rortor in all cases when at TDC or 27 degrees BTDC.

[pbanders]

You should open up the dizzy and inspect the mechanical advance. Clean the assembly with contact cleaner or some other spray grease remover, then re-lube each pivot point with a small amount of heavy lithium grease. Make certain the counterweights move smoothly and freely. I strongly suggest against trying to remove the upper shaft to get at this, as the c-ring that holds it on is difficult to remove and replace. If you think it needs more work than this, send it to John Larson on Rennlist, he can completely restore it.

[78911]

The shaft the rotor is on is part of a "two shaft" assembly that alllows the centrifical advance to work. What happens is the lubrication that allows the rotor shaft to move gets gummed up.
It is lubricated by removing the rotor and adding a few drops of oil the the felt pad at the bottom of the shaft. In your case, I would remove the pad with a longnose pliers and put a little brake cleaner or thinner in the shaft to see if it "frees up". Then add a little light oil to the shaft and the felt pad.

Ken

[Dave at Pelican Parts]

The red mark on my fan is 27 deg BTDC, the stock 2.0 timing mark. The white blob to the right is the TDC mark.

--DD

[pbanders]

Originally posted by 78911
The shaft the rotor is on is part of a "two shaft" assembly that alllows the centrifical advance to work. What happens is the lubrication that allows the rotor shaft to move gets gummed up.
It is lubricated by removing the rotor and adding a few drops of oil the the felt pad at the bottom of the shaft. In your case, I would remove the pad with a longnose pliers and put a little brake cleaner or thinner in the shaft to see if it "frees up". Then add a little light oil to the shaft and the felt pad.

Ken

Very good advice, I forgot to include this in my post. On a lot of old Bosch dizzy's, it's apparent that the felt pad was NEVER lubricated after the unit left the factory - no wonder the mechanical advance gets stuck!

[Bruce Allert]

I got the dizzy apart down to the springs. Took them off expecting to be able to lift out the assembly below. I didn't get it out since I really didn't know what I was doing! Rather than force anything I just sprayed electrical contact cleaner into it. Should'a seen the gunk come outta there. Rusty liquid too. The cleaner is a fast evaporative type so it was dry in a matter of minutes. I re-assembled everything only to be stumped for a while by the ball bearing that magically appeared from no where. Found its resting place after some help from Dave Blackburn (thanks Dave).
It's very understandable that all those whirling thingys in there need lubrication, especially with all that junk that accumulates within.
Now, even tho I put it all back the same way it came out, connected everything... it won't start. It sputtered a couple times but nadda. Reset the points, checked TDC @#1, Re did the points again. Even took the dizzy out to see if it could be put in 180 degrees backward..... nope! I might have screwed up the condensor so I'll get points & cond. tomorrow & see if that helps.
thanks guys
bruce

[pbanders]

Just removing the springs from the mechanical advance won't free the top shaft. In the recess at the top of the shaft you'll see a felt pad. Remove it and underneath you'll see a C-ring holding the upper shaft (hollow) onto the main dizzy shaft. Removing this C-ring is difficult due to the limited clearance. Instead of removing it, spray penetrating lubricant down it, until the shaft move smoothly with respect to the main shaft. Lubricate with a couple of drops of motor oil, replace the felt pad, and saturate it with a couple of drops of oil.

[jackmech]

If your car still won't run, make sure the distributor is pushed down all the way. It can very easily get held up so the teeth at the bottom of the dizzy shaft don't connect with the drive gear. You can check by taking off the dizzy cap and having someone crank the engine. If the dizzy isn't in all the way it won't turn or will turn erratically. Make sure it's all the way down. Did this myself last week and took me about 10 minutes to realize what was wrong.

[norustscott]

If I go back to your origial problem...did you take out the plate the points are secured to. Clean the two halfs and reinstall with the little ball bearing? Lubed? not to tight? Attached the vacuum advance arm? I think it is the vacuum advance diaphram that makes the rotor return to position as weel as the mechanical advance mechanism...springs?

Next, during the disassembly did you take the drive thingy( with the wound srig that holds the roll pin in place) of the end of the shaft? Did you mark it to put it on the same way it came off? It is offset...I don't know if it makes a difference or not...Think it would.

just some more thoughts.

[pbanders]

Originally posted by norustscott
If I go back to your origial problem...did you take out the plate the points are secured to. Clean the two halfs and reinstall with the little ball bearing? Lubed? not to tight? Attached the vacuum advance arm? I think it is the vacuum advance diaphram that makes the rotor return to position as weel as the mechanical advance mechanism...springs?

Next, during the disassembly did you take the drive thingy( with the wound srig that holds the roll pin in place) of the end of the shaft? Did you mark it to put it on the same way it came off? It is offset...I don't know if it makes a difference or not...Think it would.

just some more thoughts.

Unless the main shaft bushing needs to be replaced (John Larson does this using parts from Volvo), there is no need to remove the drive and shaft from the body.

The vacuum advance/retard cell drives the movement of the points plate by vacuum action only, no springs are involved. The fundamental nature of the action of the vacuum system and the mechanical advance are independent systems. The mechanical advance operates by changing the position points cam with respect to the main shaft to alter the timing. The vacuum system operates by changing the relative position of the points with respect to the body of the distributor.

Even if the points plate was totally locked-up, the mechanical advance would still operate, and vice-versa, if the mechanical advance was locked, the vacuum system would still work.

When cleaning and re-lubing the points plates, I would suggest using a small amount of light lithium grease, or even motor oil between the plates. Heavy grease may interfere with the smooth operation of the vacuum system or limit the total movement if it gums up.

I recently pulled my dizzy and did a full cleanup and relube. Prior to doing this, I thought it was operating pretty well, but afterwards, I had more stable timing (less mark wander) and smoother operation of the vacuum system. Takes about an hour and half from beginning to end of the job.

[Bruce Allert]

Well, between getting the C clip on the vacuum advance arm and reading your post, Brad, I now know that it doesn't run... still! I don't know what I did to accomplish this but I will go out and remove the dizzy once more if only to replace the O ring that is broke.
The dizzy can only go in one way, right? If you take it out & don't turn the motor over it should go right back in. It seems it should go in the right way even if you turn the motor over. I'll re-read the dizzy install scripts & see where I went wrong.
bruce

[pbanders]

Yeah, it only goes in one way, and it's amazing how many ways that it's possible to screw it up! You can get it in partially (lots of people have done that). Or you can be really creative like me, and put it back in, and have the clamp rotated so that the hole doesn't go over the stud in the case, and blindly tighten the nut back down without checking!! Took me a while to figure out why the car had about 50 degress of advance

[dave blackburn]

When I installed my MSD ignition I took my dizzy appart to oil and clean everything. I removed the part on the very bottom of the shaft that sits in the drive gear. The part with the pre load spring that turns the dizzy shaft (at a loss of a name for this part??). Well I put my dizzy all back together not realizing what way I installed this part back on the dizzy shaft. This part only will fit in the drive gear one way, but it can fit on the shaft two ways. It will still look like your engine static timing is still right, but when I tried to start my car I got some loud backfires! It kinda seemed like it wanted to run sometimes as well. It took me about half an hour to realize my mistake. Only two minutes to punch out the pin and turn the part 180 degres and get the engine running great!! If you did not remove this part, this will not apply. Just a thought, GOOD LUCK, Dave

[Bruce Allert]

I'll take the dizzy out tomorrow and look to see if I did what Brad did. I will, also, replace the fairly new condensor as a just incase.
If, after replacing the dizzy, it doesn't start I will suffice it to say I...