[Vwdiesel] Injection Pump talk ---- ( testing pump for wear )

[slatersfb at aol.com]

Last pump I disassembled had pitting on rollers - sort of like pitting on noisy roller bearing. After reassembly, I did just as you suggested with a dial indiicator & showed quite a variation in pump strokes. 
Nearly a tenth of a mm difference. Surely this would affect performance. What is acceptable variation?
 
Bob in Entire State 
 
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I write this mainly for Shawn Wrigt ----- it may be of help to others..

We are back to the Val Christian -Hagar --- managing for ECONOMY  ---lot of 
judgement and
experience involved.

First lets test Cam assembly ------- clamp pump in a good solid vice or the 
like.
install a sensitive dial indicator , as for timing pump.
Use a socket and a breaker bar to turn pump slowly while watching indicator..
There are  4  lobes on plate  ---indication shall be smoooooooth ---all lobes at 
same maximum and no
jumping of pointer.   Many turns are needed so all the rollers had a chance to
show if there are flat spots or corrosion. ---- or buildup of varnish.
You got the drift of it.  ----VERY  --important test every time you have the 
pump on
the bench. -----next  we test the Vane pump and the high pressure piston.

For our South African ,Finnish,Australian,UK  members. Some time ago we had a 
major disaster
here in North America.  ----The Roosa Master and Bosch pumps  vere destroyed by 
BAD BAD fuel.
A lot of those pumps are still in circulation so we have to test. (distributor 
pumps).

Most of these old Bosch pumps have a stroke of about 90 thou inch and a 9 to 10 
mm piston.

Here is where the experience and judgement starts ---WHAT ? if you have a lumpy 
stroke ?  ----we deal with that later.   First we ask the "Pump Gang" for some 
input.

Reminds me of the cracked heads ---cracks are ok --up to a specification by VW.
Likewise  ---a small lump ? may be ok.

Hagar.

PS :     we sure need a retired bosch member ---
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