The definitive word(s) on R1 vs R2 fuel injectors

[mdsalemi]

I made an inquiry directly to Bosch. Dietrich Kuhlgatz, the Director of Historical Communications replied today:

...the injection valve 0 437 004 001 (DC8C45R1) was released in March 1963 and was replaced in February 1966 by the injection valve 0 437 004 002 (DC8C45R2). Both nozzles have a flow rate of 165-180 L/h, work with an opening pressure of 16-18 bar and the injection pin angle of 45°. The difference lies in the design of the fuel filtration at the inlet of the nozzle and in the design and bearing of the nozzle pin...

I've attached the vintage data sheet they sent me, in German of course. Maybe one of bi-lingual members here would be so kind as to create this in English for the benefit of everyone here, then BOTH the English and German versions be uploaded to our tech manual.

Based on the release and replace dates above, I would suggest that at least all 280s, and perhaps all 250s, and some of the 230s had the R2.

[christoph]

Thank you Michael for doing the work and to get this information from the horse's mouth

[BlackForest]

Thanks Michael for the new information.
I was going to reply with some info on the previous thread but you beat me to it!

Simply put, the R1 injector was matched to injection pumps with the original cone delivery valves, which were derived from the diesel pumps and first used for gasoline on the 300SL pumps.
The 250SE/SL pump has the distinction of being the transition pump from cone valves, to the ball delivery valves we are all familiar with in all 280SL pumps.

The original 250 pump with cone valves is the R18, which was made Nov 1966-March 1967.
The second version for the 250's was the R18Z made from April 1967-Sept 1967. This was the first gasoline injection pump utilizing the newly designed ball pressure delivery valves.
The final version of the R18Z had a different 3D cam, but still used the ball valves from Oct 1967-Dec 1967.

The US version pump for the 250's was the R18Y, and always had the ball valves.

Even though the R2 injectors were first released in Feb 1966, they were not used on any 230SL pumps (R11).

The pump testing and calibration literature explicitly states that all pumps tested up through the R18 pumps with cone valves must use the R1 injector on the test bench.
All pumps after March of 1967 must use the R2 injector matched for use with the ball pressure delivery valves.

I have a bench with R1 test injectors used to calibrate R11 and R18 pumps, and another bench with R2 test injectors for the R18Z/Y and all R20 pumps.
In reality I have tested the same pump on both benches with no appreciable flow discrepancies, but who am I to question Bosch!

Regards,

Michael

[Pagodateil]

Thank you Michael
I love this type of old documentation I just create the english version let me know if i made some mistake.

[mdsalemi]

Pagodateil: thank you for the translation. You, from France, beat any of our many bilingual German/American members to the task!  I am sure one of them will make a correction or two...

Michael at BlackForest: Thank you so much for that great information. What makes this information so good is it shows all the connections and at least some of the fuel injection pump usage along with injector usage. I think this is important because we have here, as you probably well know, all kinds of these pumps of all vintages being put on all kinds of cars. I don't think it's intentional but some owners inherit this, and others just got what they could get their hands on.

I'm a strong believer in going to the experts, and we've known you to be one of them for a long time. Nice to hear from you on a topic you are very familiar with!

[mauro12]

Hello guys , that's very interesting . I've recently overhauled my injection pump , Hans Fritszche in germany did the job. My car is a 250sl but has the r22 pump tipical of 280se/sl . He replaced the space came nr 22 with the space cam nr 8 tipical of r18 pump. He also tuned the pump accordingly to the r18 specific and the car is running perfecly. He also replaced some leaking delivery valves in position 1 and 4. He told me also that r2 injectors are compatible with my pump but since they are the only available , i guess we have no alternative choice. The important thing is not to mix r1 and r2.