BOSCH Distributor Rebuilding Service

[mdsalemi]

We all know that Dr. Benz, Dan Caron, is experienced and offers a distributor rebuild service.

I have another recommendation whom I've used twice now: once for my existing distributor, and once for the "spare" that I managed to get together.  This source is Glenn Ring.  Glenn is on Long Island, New York.  You can find him at www.glenn-ring.com

Well known amongst Porsche and VW tuners, he is slowing getting into the Mercedes arena as asked for.  The distributors he rebuilt for me were the cast-iron -051 units.

The distributors come back cosmetically correct; looking very nice and of course functional.  You'd be surprised how much crud, dust, grease, dirt etc. can build up inside after 30+ years.  Glenn takes  them completely apart and rebuilds them as needed with existing and new parts as required.

Michael Salemi
1969 280SL
Signal Red w/Black Leather
Restored

[Longtooth]

Micheal,
My original -51 is in relatively good cosmetic condition, but my shaft or bushing is worn some... making it a bit difficult to get timed to spec's... I have to put a little bias into it to get it right while running (and get the advance right at rpm).

I've just written to Glenn Ring in NY and asked how or if he handles this aspect... but would like to know whether you or others with experience with the  -51 distributor have any advice related to wear of bushing or shaft.... I'm not even sure it's a bronze? bushing  bearing that surrounds the shaft.... just a guess... for all I know it's not even bushed, but it seems inconguous from an engineering only point of view to use the bore in the cast iron as the bearing, since when/if it wears then the solution is a sleave insert and re-bore to match the shaft diam. While I say this it may be, however, that Bosch wasn't worried about wear in this context... or that replacing the distributor body or shaft was a cheap enough proposition.  

Unfortunately, at 40 years a worn bearing surface isn't something an economic business mgr at Bosch would be concern with.

Longtooth
67 250SL US #113-043-10-002163
'02 SL500 Sport

[Naj ✝︎]

Longtooth,
 

quote:My original -51 is in relatively good cosmetic condition, but my shaft or bushing is worn some...

There are two bronze bushes and you could attempt a refurb since you already have a 'hone'  

Dr. Benz sells repair kits, so he could supply one when he's fit.

naj

68 280SL

[Tom]

Longtooth,

The late Randy Durance noted the following about distributor bushings:

"Distributor bushings are made of either oil-impregnated bronze-alloy ("oilite") or a porous iron/bronze-alloy. The proper alloy is important. Since the distributor receives little lubrication from the engine oil system, it must be largely self-lubricating. Most Mercedes-Benz models made before 1971 have a service fitting on the outside of the distributor to allow a few drops of light oil to be added during service work."

Hope this helps...

Tom  


1971 280sl Tunis Beige Metallic (restored & enhanced)
1971 280sl Tobacco Brown (low mileage stock)
1970 280sl Medium Metallic Blue Beige Interior (project car)

[mdsalemi]

Longtooth,

My bushings were fine.  I would suspect that your might need replacing.  When Dan Caron gets back on his feet, this might be one of the easier things for him to handle, as it is bench work.

Michael Salemi
1969 280SL
Signal Red w/Black Leather
Restored

[Benz Dr.]

I only replace bushings that are bad or worn. If the shaft is worn it makes a good repair almost impossible. The new bushings in my kit are bronze oil-light type and are self lubricating but I still drill into the bushing after removing the oiler cup so that the felt wick bewteen the two bushings gets oil. I use a small rat tail file to clean up the drilled area and then test fit the shaft from the bottom. If it doesn't fit I usually just keep at it until it does - I don't have nor use a reamer or hone, it's not needed.
The object here is to have the shaft turn without binding and have as little play as possible. I rarely ever replace the bottom bushing as it's not worn in most cases. A good distributor should hold dwell up to and beyond 6,000 RPM  A distributor machine is a must to get all the fuctions set right. After that it's just points replacement once in a while.

Dan Caron's
 SL Barn
benzbarn@ebtech.net
 slbarn.mbz.org
  1 877 661 6061

[Longtooth]

Thank-you all....much gratitude is deserved to you all for both the fast responses and details provided.  It's genuinely amazing that this site's participants are so, what shall I say... well mannered and helpful beyond belief sometimes.... i.e. sometimes beyond belief.... but always helpful.

OK, so much for the accolaides... next obvious questions now are

1. Is it likely that Bosch has the spec's on bushing's for the -51 distributor, and shaft diam spec's and tolerances... min/max clearance, or runnout etc. available by requesting or is this level of detail not already available somewhere else?

2. If the shaft's worn, then new bushings might help the problem, but won't cure it entirely, no? BUT, isn't it simple enough to have a bronze oilight oversize OD and ID bushing machined to match the press fit? into the housing and the OD of the worn shaft shaft to get the proper nominal design clearance?

I ask the above since it would seem a simple matter to get the bushing correctly sized to match a worn shaft and also surface finish the shaft's OD bearing surface while at it... true it up so to speak and remove the damaged/worn surface.

Longtooth
67 250SL US #113-043-10-002163
'02 SL500 Sport

[Benz Dr.]

That's not really needed in most cases. A lot has to do with how I install the bushing with perfect fit on a non worn shaft being relatively easy to do. If I need a bit tighter fit I peen the bushing a bit or leave the drilled hole a bit tigher. A small amount of play at the shaft won't hurt that much and can be adjusted out by point gap.
I do know this though...if the distributor isn't working at least close to spec your performance will really suffer as it affects everything. This rebuild should be considered as part of a normal tune up procedure and not thought of as '' Gee, I wonder if I need to do this ? ''

Dan Caron's
 SL Barn
benzbarn@ebtech.net
 slbarn.mbz.org
  1 877 661 6061