Greetings to all,

I am wanting to replace the vacuum advance on my '87 V-12 (and two others '86 and '89) I recently bought to refurbish.
I have read Kirby's book about buying a Chevrolet part and then doing some kind of surgery to swap parts. I don't really see me doing that.

My question is really about removing the roll pin to enable the vacuum advance to slide out of its sleeve. I am hoping this can be done without removing the entire distro.
I can't seem to find a proper size punch to tap it downward. Suggestions?

If I can't get the pins out what it the effect on the engine on leaving the current (original) VA units in place assuming the diaphragm's are toast or will be soon considering their age.

BTW......this is all part of a significant refurbishment effort: new fuel hoses everywhere; new belts; new hoses; cleaned and pressure/spray pattern tested fuel injectors; new plugs; new fans for two of them; new filters; fluids; brakes, brake line hoses, pads, calipers; shocks; suspension bushings; ball joints.

 

You need a 1.5 or 2mm punch, eg
https://www.amazon.com/Mayhew-Pro-21232-Metric-Punch/dp/B008M220PG?th=1

https://www.amazon.com/GEDORE-Splinttreiber/dp/B002S9ZHHC?th=1

I am afraid that to get the new vac capsule in, you do have to remove the gubbins from the dizzy, but NOT the dizzy itself. In this order:

1. while not essential,the job is far easier if you remove the capstan tower and coil assembly.
2. remove the cap
3. remove rotor (rock it end to end to loosen it, do NOT pull it straight up)
4. the star wheel is located onto the rotor shaft with a U shaped sprung clip. With snipe nosed pliers grip it to compress the U and pull it off. Do NOT lose it !!!
5. pull the star wheel carefully off, it is brittle so only use an ungloved hand.
6. you can now see where the rod end of the vac capsule is located onto the mechanical advance/retard mechanism. You may have to loosen the pickup chassis to get it off.
7. at this point punch out the pin and remove the old capsule.
8. It is a good mod to locate the new capsule with a tiny self tapper rather than a pin, as it is easier to remove next time!

New vac capsules are available from Manners etc etc part JLM519 . Forget the Chevy idea. Good luck!

 

Greg,
Thanks for the detailed instructions. I still need to find a set of small punches for the roll pin but was able to get the star wheel off and the plastic pieces with no issues.
Assuming 'Manners' is a local/regional store chain for you. Will check here to see if the part number corresponds to a correct match here. Could it possibly be this easy?

Not sure if I am going to keep the air injections emissions system on this car. Took it off my other one. Really like the cleaned up look in the "Vee" without it.

 

https://www.welshent.com/Electrical/...Vacuum-Capsule

Dump the air pump!

This might be worth a read too:
https://www.jaguarforums.com/forum/x...apsule-188655/

 

Try Britishvacuumunit.com
They are in the US, and can build you one with a heavy duty diaphragm ( which I recommend). I used the BVU one about 15,000 miles ago and works great, this after two of the SNG ones failed (first in 700 miles, and the second in about 5000). No affiliation but a satisfied customer.
Also, I wouldn’t recommend changing it on the car; pulling the distributor is easy and you can fix your seized centrifugal advance while it’s out.

 

"Manners" is not a regional store chain. It's a Jaguar/Daimler specialty retailer. There are several.

https://jagspares.co.uk/classic-jaguar/xjs.html

 

Brad,
have you tested the vacuum units with a hand operated vacuum pump with gauge - cheap to buy - i have all the info on what the HG should be @ start & maximum and total advance deg, no point in replacing if working.

 

My reasoning is that I am deep down into the valley and this is a great time to replace everything on a 37 year old car. Even if it works right now the odds are against it lasting much longer.

 

I got the star wheel off with no problem once I got a new set of "C" clamp pliers. The roll pin was another matter. Found a 1.5-2mm punch as part of a set at a local tool company shop (Harbor Freight). It fit into the hole fine. Gave it a couple light taps with a hammer from different angles with no movement. Gave it a few more harder taps but the punch shaft bent and then broke when I tried to straighten it out. Will put some PB Blaster into the hole and go back for a replacement punch later today. It shouldn't be this difficult to get out. Plenty of room for the pin to come out the bottom of the housing.

Welch Jaguar has new vacuum advance units - for about $70 each. Obviously very proud of them. I know inflation is rampant but surely there is a less expensive option other than finding one made in china.

The air injection system will be ditched but first I have to get a source for the 'plugs' that close off the pipe hole. I got a set from a British supplier about six years ago but can't find the contact info now. (they weren't cheap). European models did not have this system but all the intake manifolds are drilled for them so they used a solid "plug." I may just use the air pump as an idler pulley or possibly move the alternator up from it lower position onto that belt and then only need three belts IIRC. I was able to get a std idler pulley from England when I got the plugs years ago but again it wasn't cheap.

As far as the centrifugal advance goes none of the four engines ('86, '87, '88-dismantled parts car, and '89) I have seem to have experienced this. All of them "springy" back immediately when turned by hand. They move about 10-11 degrees and then snap back when released. I have serviced all with lubricating the center shaft with a compressed fabric material soaked in synthetic oil. Anything else recommended to check for or service the dreaded centrifugal seizure issue? Thx.

 

Victory!! one roll pin out. Had to get a replacement punch from Harbor Freight but they gave me a replacement with no hassles.

Recommendations on centrifugal advance lubrication and how much to use?

 

HT bearing grease was the old usual way but better result if cleaned & sprayed with silicon spray, this can be touched up yearly or earlier using a spray can with an extension tube while dissy insitu'

 

Number 2 came out very easily with the punch and light tapping with a hammer. Maybe the difficulty with the first one was just an anomaly.

 

Thanks. Too easy.

 

A couple of drops of light synthetic engine oil (0W20 or 5W20 like what new cars use). Put a little cotton in the recess under the rotor and a few drops to soak it.