Here’s a photo- car runs fine-quite smoothly but I don’t know how performance wise it’s supposed to be- I haven’t revved over 4500 or so when pushing it some. Looks as it has a spring going to that vacuum canister in order to advance.
If you connect a short piece of plastic pipe to the vac capsule and suck on it , you should see the base plate move a bit ( 2-3 mm ) if it`s working ok . Maybe squirt a bit of thin oil around in there , it looks a bit dusty .
Oh n do you know what the thumbscrew is for? Looks like it would be to adjust how much advance the vacuum would give? Since it has an A- advance? N R retard?
It is for the time adjustment, on the opposite end from the thumb screw there may be lines, I think one is longer than the others, if there is that will be the mid point of the adjustment and where it should be when setting the initial timing.
The thumbscrew allows you to make minute changes to the timing w/o the necessity of unclamping the dist. to do so. Set it at the center and use it to fine tune the position of the 10 degree mark on the damper when you are tuning it.
Damn I haven’t timed a car since the 70s. I’ll have to get a timing light ( do they still sell them?) or trust the local JA to do it right. Prob a YouTube on it?
I bought one several years ago, solely for the Jag to set up the timing after a rebuild. Used it again when I installed the 123. Other than that, I’ll probably never use it again as None of my cars have points!!! Ok, I’m ducking !
Didn’t see it move but I may not have sucked hard enough- (on the vaccine canister with a hose) I plan to use a syringe or diaphragm could be understandably aged n busted. I do have the MSD so I don’t even see points to adjust-n DO I even have to time my car??- the distributor can be turned w my hand (not tight) n car runs fine.