Distributor Vacuum Canister Comparisons – Are Reproduction Canisters The Answer?

Hendrik “Hank” Blommers, of Ontario, Canada, contacted Eric Shoemaker concerning Vacuum Canisters for Stock German Distributors. Hank is concerned because the supply of viable used parts is dwindling. Most of us are relying upon what we can scavenge here and there. I have relied upon large parts-lots which I have purchased over the years. I have saved Distributors and their parts for my personal use and for a rebuilt Distributor to sell, now and then. Scavenged parts, so far, have been sufficiently numerous for needed repairs

Nevertheless…the thought of dwindling parts prompted Hank to investigate.

Hank’s interest stems from the fact that he owns a “…1966 Canadian Standard Beetle (1200cc, no chrome) since 1971. I purchased (it) from my Mum for $400 and she purchased it brand new in November, 1965. Bone stock and all original”.

Since Hank’s ’66 Beetle is the “Standard” Beetle, it came with the 1200cc Engine (rather than the 1300cc Engine). Thus the Distributor for his car is the same as the one for 1965 Beetles—the ZV JU4R3. The Vacuum Canister for this Distributor falls into the same category which is of interest to this study.

Hank discovered a European source for Reproduction Vac Cans which closely resemble those used by Bosch during years 1965-1970. He determined to buy 4 with the aim of testing to see, first of all, if they are viable. Do they take and hold a vacuum? And—will they meet a given Distributor’s requirements for proper operation?

Hank put forth the idea of sending one of the Repro Vac Cans to me to test for viability. The Canister soon arrived and I began an inspection process. I involved some close VW friends as well as Kurt and Adam Troeger (https://1967beetle.com/passing-the-baton-a-vintage-sun-distributor-testing-station/ ) . As our investigation progresses, I will post results.

For the purposes of this discussion, I am confining my study solely to the following Type 1 (Beetle) Distributors:

• 1965 (ZV JU4R3) 0-231-147-002/111-905-205L/M; Vac Can#1-237-121/111-905-271B; Operating Arm #204
• 1966-1967 0-231-137-009/113-905-205K; Vac Can#1-237-121/311-905-271; Operating Arm #210
• 1968 0-231-137-021/113-905-205M; Vac Can# 1-237-121/113-905-271B; Operating Arm #279
• 1969-1970 0-231-137-035/6//113-905-205T; Vac Can# 1-237-121/113-905-271B; Operating Arm #279

Examining and Comparing Canisters

Our son, Kevin, and I measured the Diameter of the Reproduction Vacuum Canister which Hank had sent. It measured approximately 83.71mm in Diameter.

Then, we took measurements of used, vintage German Bosch Vacuum Canisters which the Reproduction Canister is supposed to replace.

The Vacuum Canisters of two restored 113-905-205K Distributors measured 85.35 and 85.23mm in Diameter, respectively. A loose Canister deemed likely to be for a -205K Distributor (following testing on a known -205K Distributor) measured 85.22mm

A Vacuum Canister on a restored 113-905-205T Distributor measured 82.96mm in Diameter.

A loose Canister deemed likely to be for a -205T Distributor (after testing on a known Distributor) measured 82.77mm.

Conclusion: The small variance in Canister “size” may not affect performance.

Wanting to know more about the unknown, I carefully disassembled a damaged Vacuum Canister. Hank already had performed a similar operation and had sent photos. But, I wanted to have the parts in my grubby hands!

Upon disassembly of the damaged Vac Can (which still had been able to take and hold a vacuum), I found a small quantity of “gelled” grease in the “bottom” of each half of the Canister (on either side of the diaphragm). Since no grease can migrate between halves, I am assuming that the grease in the front half (away from the Distributor) must have been installed into the Canister by the Manufacturer. I do not know the reason. Possibly part of the assembly process? Hank and I discussed this discovery and agreed that there absolutely is no way for grease to pass from one half to the other. If there were, the Canister certainly would not hold a vacuum. [Due to the opening for the Operating Arm of the Diaphragm, where it enters the “backside” of the Canister, it IS possible that some grease could get into the back half of the Canister over the years]

The feature on the Reproduction Vacuum Canister which first catches the eye is the Tube for the Vacuum Line—it stands at an angle away from the Canister rather than being affixed in a straight (standing) position. Just for interest sake, I’ll include a comparative photo of this feature. Otherwise, it has no bearing upon the viability of the Reproduction Canister.

There is what I call the “Bracket” which allows the Canister to be attached to the Body of the Distributor. There appear to be two sizes of these on Vacuum Canisters for Distributors for years 1965 through 1970.

The Reproduction Canister has a Bracket like the more narrow, black paper cut-out.

Unknown is which Canisters, with which Brackets, were destined for which Distributors. Not having known “virgin” (untouched) complete Distributors or good photos of untouched Distributors for years 1965 through 1970 hobbles my effort to correctly assess these Brackets.

The Bracket of the Reproduction Canister is lacking the Hole for the Condenser Tab. We did not drill this hole because it was not important to our testing procedures. Hank did drill the hole in the Bracket of a Canister which he is testing in Canada.

The back of the Reproduction Canister compares favorably with that of the ’66-’67 -205K Distributor Vacuum Canister. Note the “star-like” pattern on the back. I assume that the German Canister is for a ’66-’67 Distributor since machine test results were within specifications.

The Operating Arm of the Reproduction Canister had a hole too small to fit over the Points Plate Return Spring Post. With Hank’s permission, I enlarged the hole using a 3/16ths inch Drill Bit so that the Operating Arm hole would approximately match the Post’s diameter. Now, we could properly mount the Canister onto the body of a Distributor for further testing.

Another point which I cannot explain (due to the lack of original Distributors which would help us to know) is the lengths of the Operating Arms of the various German Bosch Canisters.

The Operating Arm Length (visible section) of the Reproduction Canister measures approximately 1-9/16th inches (39mm). The measurement was taken from the Operating Arm Stop (on the Canister Bracket) to the end of the Operating Arm itself.

Supposedly, each Operating Arm is stamped with two sets of digits. One set appears to indicate a Date of Manufacture. The other links the Arm to a particular Distributor. I gathered 14 Vacuum Canisters for years 1965 through 1970. Two of the Vacuum Canisters are matched to two Distributors which had been tested previously on our Sun Testing Station (a -205K and a -205T). 8 of the Operating Arms bear a tiny numeric stamping: 042. This stamping occurs where the Arm extends inside the Canister Bracket just before the stop. The other 6 Canister Arms bear no stamping. This stamping could be a “Date-Code”. If so, 042 would indicate that these arms were stamped in February of 1980.

The larger stamping, which the Operating Arms “should” have, was not present on the 14 Arms I surveyed. That stamping should refer immediately to the Bosch and VW Distributor Part Numbers respectively.

Hopefully, someone will come forward with knowledge concerning how to properly identify Vacuum Canisters.

I quote from the pdf (see the Link below) where the author voices his frustration at the inconsistencies with the data which is accessible at this point in history. I quote from this Reference as follows:

“Bosch VW Distributors-Vacuum Canister Part Numbers: The 3 (or 4) digit number(s) stamped into the operating arm of the canister, are usually the end digits of the LONG number. Many pre-1970 canisters have no number on the operating arm, or if they do, it may be a date code and not a part number.”

I think that I have about thrashed the dickens out of comparisons of Vacuum Canisters. So—where does this lead us? Will there be a conclusion? CAN there be a conclusion?

I think that there CAN be a conclusion–or conclusions plural. I’m going to take that up in Part Three of this saga. We are going to do some interesting things for Part Three. Remember that I talked about that Vintage Distributor Testing Station? Well, now, it’s going to reappear, hopefully to help us in our quest for answers.

Notes:

• Thanks to Hendrik “Hank” Blommers for getting the ball rolling for this study. Hank even posted on a VW FaceBook Group in Ontario to see what information could be gleaned.
• David Brown continues to provide pertinent facts for these Articles.
• My wife, Neva, listened quietly as I went over and over the facts, trying to get things straight in my head and to separate the relevant from irrelevant. I do believe that she can recite it all—and, she knows what it all means!
• Our engineer son, Kevin, spent time with me, discussing the Canisters. We alternated playing the Devil’s Advocate. Thus, we thought of many variant ideas—ideas which we don’t have time to broach here. Thank you Kevin for bearing with my incessant questions!
• Several VW friends have examined aspects of these Vacuum Canisters and have made suggestions. I thank each of them!