Dist. vacuum advance can?

[vwbill]

Hey can you change vacuum cans or is the travel so different? My vacuum advance is leaking it has the 979 running the arm length and 917 across the tip. I have a vacuum can from a 205F dist. My dist is the 022-905-205P/0231-172-019. Can you send them to someone for rebuilding?
I'm getting the back fire when I accelerate. Thanks Bill

[raygreenwood]

The 905-205P generally used the 917 stamped arm with the adjustable advance arm. The real difference is not always the arm length or throw, its the "rate" or speed the can advances at a given rate of vacuum. The spring pressure inside governs this. On the pull rod side, you can see the "notch" in the arm that sets the throe lim it. That cam be lengthened carefully with a dremel and a carbide burr...if you find a can that is too short. There are a handful that will work correctly. The trick is to not worry too much at first about the throw of the arm. Get a hand vacuum pump and a small straight edge or dial indicator...and measure what each can advances to as you increase the suction 1" of mercury at a time. When you find one similar to the 917, you can increase the throw if necessary by widening the stop notch right on the inside of the mount where it goes up against the side of the distributor.

The outside stop limit screw can be installed on almost any can. Here's how.
First way is actually harder than it at firt looks. Find some of the press in/pull in flanged inserts with teeth around the outside. You will need to trim the length down by about half. Carfully drill a hole...clean out the filings and press in a 1/4-20 insert. Seal with a smooth bead of JB weld.

The other way. Rent or borrow a low amperage mig welder...or if you are good at silver soldering...with a butane torch....that works great.
Drill the hole in the can...clean out the filings. For a thread flange, you will use a piece of 3/8" rod. Cut is about 5-7mm long. Clamp it down, drill a hole through it. Thread it 1/4-28. Thread the bolt into it.

Now....in a pot of cool water...with the advance vacuum spigot pointed away from you, clamp the advance unit down so its submerged to a little above the seam on the center of the can. Fill it with water...so its about 1/2-3/4" from the top. This keeps the diaphram cool. You can now either solder in the tube nut you made...or tack weld in the tube nut you made. Is actually safer to solder it. Try a couple of broken advance units first for practice and to set the heat range. This works nicely. Ray

[raygreenwood]

The 905-205P generally used the 917 stamped arm with the adjustable advance arm. The real difference is not always the arm length or throw, its the "rate" or speed the can advances at a given rate of vacuum. The spring pressure inside governs this. On the pull rod side, you can see the "notch" in the arm that sets the throe lim it. That cam be lengthened carefully with a dremel and a carbide burr...if you find a can that is too short. There are a handful that will work correctly. The trick is to not worry too much at first about the throw of the arm. Get a hand vacuum pump and a small straight edge or dial indicator...and measure what each can advances to as you increase the suction 1" of mercury at a time. When you find one similar to the 917, you can increase the throw if necessary by widening the stop notch right on the inside of the mount where it goes up against the side of the distributor.

The outside stop limit screw can be installed on almost any can. Here's how.
First way is actually harder than it at firt looks. Find some of the press in/pull in flanged inserts with teeth around the outside. You will need to trim the length down by about half. Carfully drill a hole...clean out the filings and press in a 1/4-20 insert. Seal with a smooth bead of JB weld.

The other way. Rent or borrow a low amperage mig welder...or if you are good at silver soldering...with a butane torch....that works great.
Drill the hole in the can...clean out the filings. For a thread flange, you will use a piece of 3/8" rod. Cut is about 5-7mm long. Clamp it down, drill a hole through it. Thread it 1/4-28. Thread the bolt into it.

Now....in a pot of cool water...with the advance vacuum spigot pointed away from you, clamp the advance unit down so its submerged to a little above the seam on the center of the can. Fill it with water...so its about 1/2-3/4" from the top. This keeps the diaphram cool. You can now either solder in the tube nut you made...or tack weld in the tube nut you made. Is actually safer to solder it. Try a couple of broken advance units first for practice and to set the heat range. This works nicely. Ray

[vwbill]

Hey Ray, I just order the A1-Cardone 31915 reman dist. from PartsAmerica.com(AdvancedAutoParts)(was Discount) for a 1973 1.7L(EA) 412 and got it today from Cali. It was funny though since the case had 0231 172 009/311 905 205AE on it so I was thinking it was the wrong dist since My dist is the 022 905 205P 0231 172 019! I thought at first maybe someone put the wrong dist in as the core, lol! I ended up calling A1-Cardone direct and talked with the Tech ASE and he told me the case isnt what they spec the dist. to and checked the specs they use for that dist and told me it was 30 degrees adv. so they do a running dynamic setup for dist. to the specs for the vacuum can and the advance curve.
I never knew that! It had the FI points and a new point plate and points/condenser and vacuum can for 55 bucks. I hope its right! I'll know tomorrow and let you know. I guess you cant always trust the numbers on the dist. if its a rebuild in the car! Thx Bill

[DeathBus]

bill I am interested if this dist. you got will work, good luck!

[raygreenwood]

Thats a good deal...but be careful. You will notice that many re-man places sand blast the #'s off and re-number to the application they are selling it for. They take no heed as to which model of FI vehicle it was. The FI trigger cam positions are slightly differently located in some models. Its not a huge deal, but when you get the advance set right, it may idle oddly. Considering all type 4's had the same cam... it should be no problem. But...once I got a type 4 distributor body with a type 3 cam guts for the FI. It was ugly. The trigger points were also incorrectly adjusted and had poor spring tension and resistance....something else they don't really care about at re-man houses. The vacuum advance can was the wrong one. I stripped the new bushings and polished shaft out of it and dumped it in the trash. Basically anew bushing set for the $45 I spent. Measure everything. Ray

[vwbill]

Hey, got the reman dist. in. I had to change the condenser with my old one since they used the one with the point plug hold down as part of the condenser and I have a seperate clip that holds the point plug to the body and the condenser mounts to the vacuum can screw. It was missing one of the dist cap clips but I had a few. I have a question about the top shaft alignment. Does the cutout for the rotor on the top shaft if you are looking at it and pointing to you then does the bottom small side of the lock drive key face to the right or left? I have a L-jet dist and the small side faces to the left; I have a 914 dist and the small side faces left and the reman faces left, but my old dist has the small side of the key to the right and the cutout is a little to the right not in line with the bottom lock key? If this is wrong would the injectors fire wrong? The car runs and does accelerate good but the idle is cycling now when it was stable? I though that cycling is a vacuum leak with the manifold hose to the air regulator? Also, when at TDC the rotor faces to the right rear of the car? Thanks Bill
p.s. Had to ask what makes the advance curve? Is it the point plate or the travel of the vacuum can or is it both the mech. adv and the vacuum advance? So if I replace the point plate with the same as my dist with 27degree adv(30) and use a new vac can with two vac lines does that mean I'll have the same adv. curve? I guess what I'm asking is how did they reman it to my dist specs? Thx Bill

[raygreenwood]

I have to stop at the storage unit to look at one. Probabaly later today. Ray