Looking for an exploded view of a VJR 4 BR 18 distributor

[Max Cooper]

Can someone please post an image.

Thanks, Max.

[Brad Ripley]

Here is a drawing of a distributor common to the BR 18. I do not know of a drawing specific to the BR 18. Also enclosed is the parts list for this distributor in next post.

You may find some other information in the Bosch Tradition website: http://www.automotive-tradition.de/en/w ... herche.htm First set up an account. Then look for Recording Tables to x-ref the old number to the 10-digit Bosch number. Then put that number into Spare Parts List where you will find spare part numbers.

[Brad Ripley]

Parts list for above distributor.

[Max Cooper]

Thanks Brad Ripley!
I looked through the Bosch site. Couldn't find anything about "shimming" the distributor, for proper shaft "play" though.

Does anyone wish to share these figures for a VJR 4 BR 18?

Thanks, Max.

[Ron LaDow]

Max,
I doubt you'll find a published spec for that. Bosch never presumed the distributors would be refurb'd; they were to be replaced.
When I asked, Don Marks (rip) said zero end float, and I can see that is the ideal. It's not easy to hit, and Don favored used fiber washers to avoid the 'first wear' issue.
Any end float is ideally removed with the spring in the center of the drive quill, but that thing doesn't seem up to dealing with high RPMs.

[Brad Ripley]

Suggest use of one of our Registry advertisers for complete rebuilding of your distributor. Maybe one of those vendors can supply an exchange unit in a couple of days.

[Max Cooper]

Ron LaDow wrote:
> Max,
> I doubt you'll find a published spec for that. Bosch never presumed the
> distributors would be refurb'd; they were to be replaced.

> When I asked, Don Marks (rip) said zero end float, and I can see that is
> the ideal. It's not easy to hit, and Don favored used fiber washers to
> avoid the 'first wear' issue.

> Any end float is ideally removed with the spring in the center of the drive
> quill, but that thing doesn't seem up to dealing with high RPMs.


Thanks for that information!
That seems logical enough for me. I'm thinking I will use new fiber washers (two large fiber washers have disintegrated) and re-shim the distributor after it "breaks-in".

Speaking of 'first wear' issues. I have heard a rumor of soaking the entire distributor in oil vertically, until shy of the under-side of the advance plate, prior to installation. I'm thinking this is to facilitate lubrication until the "screw-groove" starts pumping oil.

Regards, Max.

[Ron LaDow]

Max,
If you work on your part, you'll find the shaft and the bushings are amazingly un-worn, unless it was sitting in water. There's also a piece of felt in between the bushings which holds oil.
Pretty sure it won't need any further oiling.

[Mike Horton]

" When I asked, Don Marks (rip) said zero end float, and I can see that is
> the ideal. It's not easy to hit, and Don favored used fiber washers to
> avoid the 'first wear' issue."

I've found the new fiber washers seem a little thinner than the originals, and yes, there is an initial wear in of the fiber washers, and when set up with Don's referenced "zero" dimension, will find the extra running clearance pretty fast, but after wear in, settle down. I find very little mechanical wear in these factory units, unlike what has been written, and it will always be in the same parts, and is IMHO, a wear in of factory production parts, and yes, almost never in the areas Ron mentioned. The felt pad is only in the 022, 031, 061, but the BR18 runs in the as machined bore in the cast iron body, again, with almost no wear, when assembled correctly, and properly pre-lubed. These Bosch factory distributors are very well designed, well built, and in my experience, the best ever produced for the 616 engines. Don't waste your time seeking Don's "zero" end clearance, it runs well up to about .015", and I've seen many with more. Clean, and well lubed (sparingly in the right places), is the path to success.
Mike (every one needs a hobby)

[Mike Horton]

...oh, that parts break down is the closest I've found, and the only important omission, is in the extra figure # 26 & 25 shims, which install on each side of the distributor body bore in the lower section, the two fiber shims go against the cast iron surface, and the end play is set with the various thickness steel shims from the shim package, and shims figure # 27 & 28 are a larger diameter, and set the vertical clearance of the point cam. Alas, there is only one new fiber shim in each shim package.
Mike

[Albert Tiedemann]

Max Cooper wrote:
> Thanks Brad Ripley!
> I looked through the Bosch site. Couldn't find anything about
> "shimming" the distributor, for proper shaft "play"
> though.
>
> Does anyone wish to share these figures for a VJR 4 BR 18?
>
> Thanks, Max.



Here is some information. Not from any book but could be considered” tribal knowledge” [a reference borrowed from a son-in-law]

All dimensions are given in mm.

For the axial play, X, I use .0  X .10 and I measure with a feeler gage. With this value you can approach the “ideal” axial play mentioned by Ron in a later post and purportedly sanctioned by Don Marks therein mentioned and often revered as the Guru of distributor rebuilding by KOF. Please note, however, that the drive pin for the drive coupling is no longer centered or free to find center when zero clearance is achieved And, since a suitable combination of shims are offered in the available Bosch kits [quite pricey now--$50 or so], an incremental value of .1 mm can be achieved. There are many ways in which finer values can be achieved with the available shim thicknesses in combination with new and/ or old fiber washers. The use of used fiber washers should be viewed with cautious optimism as many are found to be quite brittle when taken out of service and examined for another tour of duty. In the rebuild kit from Bosch, there has not been two fiber washers for the axial play furnished [at least since 2004 when I first became involved with repairing cast iron distributors for the 356] even though two are shown to be required in the information provided by Brad. Maybe it is their way of saying…” use one old one”.

For the clearance, Y, [labeled Y herein for differentiation from X] between the contact point mounting plate, item 37 in Brad’s post and the stack of precision shims, item 27[AR thicknesses] and one Phenolic washer, item 28 supported by the advance cam assembly, item 29, I use .15 Y .25 and measure with a dial indicator with the axial play taken up by gravity in the holding fixture. Knowing beforehand what the actual axial clearance is allows some discretion when selecting the last shim. This assures a clearance between said items when the rotating shaft “end play” is displaced by the die spring between the distributor drive and the distributor coupling interface which, as Ron points out in a later post--is not too effective at high rpm. The interval clearance measured can further be tweaked by axial displacement of the contact point mounting plate after loosening the fixing screws, item 40, since there is clearance in the three through holes in the distributor housing, item 1. A displacement as small as .01 mm can be detected easily with a dial indicator.

Use of these criteria has served well for more than 300 distributors for the 356.

Well, it does not look like the Talk posts support the symbol font. Those funny squares are supposed to be equal to or less than. This is standard math notation.

[Albert Tiedemann]

Max Cooper wrote:

> Thanks for that information!
> That seems logical enough for me. I'm thinking I will use new fiber washers
> (two large fiber washers have disintegrated) and re-shim the distributor after it
> "breaks-in".
>
> > Regards, Max.


Just where do you have in mind to procure the "new" fiber washers used to set the axial clearance? Please share when you find them. They are special. Look closely at the material and you will see that it has the appearance of having been coined. This feature is to retain lubricant. I think Carb Rescue had them made but they may not sell loose unless they do the rebuild. It was also their policy for the sliding surface when they had them made from material that was found to be "near the original", but you can get almost the same thing from Stoddard now although the material does not appear to be is exactly the same [as Carb Rescue's and definitly not "as original".] And it might be beneficial if the latter part was puched so that when installed, the crown would be up!

[Ron LaDow]

Ab,
The ones I got from Klasse not long ago had the waffle-pattern 'embossed'. Is that what you're referring to?

[Mike Horton]

Ron, does Klasse sell these separately? I've been having to buy the shim kits, with the one small fiber shim, and re-use an old one, or buy a second shim kit. It has been my experience that these small dia. fiber shims are the high rate wear-in component. I read in an old PCA "Up-fixin" that Lukes & Shoreman (sp?) shot for .005" axial play in their early SCCA production engines, using the original cast iron distributors, and that has been my target for a while now, and it seems to work well on street engines... with the newer phenolic slide surfaces, and a good collection of orig. advance springs, I've been able to come up with a couple of real "jewels" for a near stock 912 engine.

We overhauled the early smaller Bendix magnetos in our FAA Repair facility, and the shaft end play to shoot for was (plus or minus) .0005" hard to measure, and these shafts were supported on roller bearings, the bearing races in their bores are what we shimmed... those are still my favorite aviation magneto ever built, again, due to build quality, like these Bosch distributors.
Mike

[Albert Tiedemann]

Ron LaDow wrote:
> Ab,
> The ones I got from Klasse not long ago had the waffle-pattern 'embossed'.
> Is that what you're referring to?


I am looking to buy these separately as Mike has indicated in a later post. I looked on their site and did not find an illustration or a listing for the part that you mentioned.
Perhaps there was a secret handshake involved. Finding the correct material in the "near correct" thickness is the primary problem. Bokers will make any washer that you want. At nearly $50 for the repair kit that is short one of these essential washers leaves one thinking..."what is the message that Bosch is sending"--or should I say has been sending for quite a few years now.