Century JJ (Occasional "knocking" sound)

[Tony Bandiera Jr]

Tony, I never had anything like that happen to a Century, but I have seen other strange stuff happen that is no fault of the projector. If you had rust in an intermittent, you obviously had contaminated oil that got put in the intermittent. I used to service a theater in Chicago where a disgruntled projectionist put battery acid on the gear train. That also caused a big orange, rusty mess, and everything had to be replaced on the gear side. Even the intermittent drive gear and cam had to be replaced. I installed a loaner SA and did the rebuild in my shop.

I had seen it several times on the JJ's and SA's in one particular chain in my service days, it multiple locations. Knowing that chain it is possible they used bad oil, never had it changed, or both. It was a constant at most all of their locations I and the other tech serviced. Also on teardown most if not all had destroyed inner and outer bushings, so the color was coming from the bushings for sure. Only a small percentage of them actually leaked though, which I found odd. Never had that issue with Simplex XL's for sure.

[Ryan Gallagher]

Correct on all of your statements. If the "worst case scenario" arose, it was either a full rebuild or replacement. If you flush with anything other than oil without taking the movement fully apart, you WILL have solvent residue that will contaminate the oil. In worst case scenario you'd be beyond the scope of flushing with oil anyways. That said, diesel does make a great solvent for cleaning the parts during a teardown or rebuild, but you'd still have to use a suitable cleaner to remove all residue of the diesel before reassembly.

As for pad roller oiling, I always cleaned the shafts and roller bore with alcohol, then used my finger to wipe a thin film of oil on the shaft. Install roller, turn it several times, and repeat with another thin film of oil. Never had a ny issues with oil getting on the film. NEVER just apply even a single drop of oil with the roller installed! That will just run all over onto the flanges and it won't penetrate the full length of the shaft anyways. I have used Century oil on our JJ with the method I described and it worked well. (But lighter oil like Simplex oil works a bit better.)

That all makes sense. I thought of the residue aspect after I posted. Hard to evaporate stuff from a relatively closed container.

Good answer on the rollers, because that is exactly what I did today (remove, clean, then a swipe of oil), I just thought I’d better ask before I do the rest too. Mag rollers are happy again.

Will repeat on the rest soon, but they spin freely right now.

[John Eickhof]

i have heard that tick many times both 35 and 70...it sounds to me that you need to check for end play in the flywheel shaft on the movement if it moves in and out the preload adjustment on the intermittent needs to be adjusted to rid of excessive end play it also may be that someone adjusted too tight and the ball that presses against the cam has worn a flat spot needless to say it should be checked by a competent intermittent rebuilder like Mark, or Myself, or Tony or others familiar with how the century movement works, also like Mark said the shutter shaft on a single shutter are notorious for end play and knocking against the front support bearing BG9 or the shock spring has relaxed, carefully look at it while running and see if the shutter shaft is bouncing back and forth, the same condition can happen on the vertical shaft if bouncing up and down the tension collar at the very top needs to be adjusted, it does not take much play even .01 inch will telegraph through the gear train and cause that noise!

[Ryan Gallagher]

Thanks John and all. I’m on a glorious vacation to cooler climes (Seattle) till August, but will examine the shaft(s) play situation in our run up to the next feature print.

no adjustments have been made leading up to the start of the noise, so hopefully not a prior adjustment that has worn flat spots etc.

[John Eickhof]

Ryan, do you wantme to hold that bracket and ship it when you return? please let me know, have fun!