When were ball check valves introduced on the injection pumps?

[rgafitanu@gmail.com]

I have the opportunity to get a defective injection pump to use for parts. I am interested in the ball valves. There are 2 pumps available, a R20 and a R24Y. Anybody knows which one came with the ball check valves?

Thank you

[Tyler S]

The r24 is a later pump. It does have the ball type check valves, but they will not fit into an r-18 or r-20 pump without machining work. Some later r-20 pumps did have the ball type valves.

[Pawel66]

Maybe it will help: in the BBB you have the IP listed with modifications that were made. Just had a BBB at hand, see below if possible.

[rgafitanu@gmail.com]

Thank you Tyler and Pawel, I have the BBB book but it doesn’t mention when ‘the ball check valves were introduced. I have access to a lathe to machine them. Are they longer or wider? What do I need to machine?

[Shvegel]

I believe the "Y" designation denotes ball valves.

[66andBlue]

The "Y" indicates the USA versions of the various injection pumps. See the list here: https://www.sl113.org/wiki/Fuel/Injection

It appears that the ball valves were introduced with the R21 and R22Y pumps.
Thus, to answer Radu's original question: the R20 pump does not have the ball valves.

There is now also a parts list for download in the Tech Manual.

{Crossed out statement about R20 IP, in light of A. Dalton's later post}

[A Dalton]

 Late R18 were upgraded from cone  to  ball valves  [ R18z / 250sl]

R20 pumps had ball.
R22 the balls size  was increased to 4mm.
R24 is the replacement and they retained the larger balls [ 4mm]

[rgafitanu@gmail.com]

Thank you, I am assuming that the 4mm ball valves will need machining.

[Shvegel]

Pretty easy machining.  just a cut in diameter.  15 minutes apiece max.