Rebuilding R24Y FIP with 3d cam from R20Y for M130 engine.

[bracurrie]

I have a theory based on the BBB, recent conversations with re-builders and remembrances from back in the day. IF you were to rebuild a R24Y Bosch FIP using a three dimensional cam from an R20Y FIP you could get better drivability and performance.
Are there any other factors to consider or impacts to drivability and performance that might be unintended consequences if just that change were made. Changes to ignition timing systems and old style throttle body vacuum are also on the table for consideration.
Thanks ahead.
Brad

[bracurrie]

Other thoughts: Someone told me in a post on another forum that fueling specs for the R20Y and R24Y are identical.

[Cees Klumper]

To be honest, there are so many things that affect performance that I would worry more about getting everything back to factory spec, or as close as possible, first, and only then start tinkering with adjustments. Because unless the car is running perfectly well, you will never know whether putting on a Frankenpump was a good thing or not.
Also, these pumps, in good shape at least, are of course getting more and more valuable, so experimenting with a good one may end up costing you dearly, if it's not possible to get it back to how it was. From my understanding, only real experts can handle these properly, using rare test and calibration equipment.
In short, I would 'leave well enough alone' and only go for tried-and-true improvements, like 123 ignition. But that's just me!

[Shvegel]

bracurrie,
That was me on Facebook.  the 22Y and 24Y are the same.  The 20Y probably does have a richer Space cam.  Too bad Hans from H and R is gone.  He used to customise space cams for performance vehicles.  You will have to use the specifications for the R20Y pump if you are to get a benefit from the R20 space cam.  otherwise you will just detune your space cam to the R22/24 specification.

[bracurrie]

Cees,
You are so very correct about getting the basics right.  The only thing I don't have working to factory spec is the speed switch and ignition retardation system.  It's disabled because it wasn't working properly.
Ignition system has been checked and is working properly with the correct spark plugs, wires etc. I recently replaced my gas tank because I had a persistent rust issue. Fuel system purge and several tanks of gas later the drivabilty of the engine has improved dramatically.  But persistent minor idling issues, except when the engine has been run hard for 15 minutes, and after confirmation of adequate fuel flow and pressure led me to believe the FIP needs some love.  I am pretty sure that someone fiddled with the fueling screws on the FIP so I believe a good cleaning and calibration would help. 
Because the stock setup in 1970 was a leaner with less tailpipe CO setup, drivability was compromised compared to the 1968-9 setup so I am trying to tweak the setup to the 1968-9 specs.  I am trying to accomplish this by doing the following:
1 - Having an R24Y rebuilt by a Bosch qualified re-builder with a three dimensional cam from an R20Y using specs from the R20Y.
2 - Install a 123 Ignition dizzy that can set advance curve in software.
3 - install vacuum source in throttle body for variable vacuum to drive retardation/advance in the dizzy just as the 051 distributor used that vacuum.
4 - Program the 123 Ignition dizzy to behave like an 051 with some cold and hot start advance blips to aid starts.
Other details: The fueling specs for the R22Y and R24Y are identical. The R20Y is different and its the FIP that was in the 1968-9 version of the engine.
I am not modifying the FIP on my car.  While it may benefit from a cleaning and adjusting it works well enough to drive the car as is. I found another R24Y this is in good condition and a re-builder that has a three dimensional cam from an R20Y available for me to have.  I put the car on a dyno and did several pulls to establish the baseline operation of the car as is.  While dyno results vary, I was told that the dyno I used reports lower but thought to be more accurate results. 126 HP at 5400 RPM.
We will see what the improvement is after tweaks.  More importantly to me will be the subjective improvements to drivability.

[Shvegel]

You should be able to get manifold vacuum on the inboard face of your valve body near the intake / throttle body line.  That is where the automatic cars connect the vacuum operated throttle control to maintain a constant idle.  If you car doesn't have the fitting you can probably drill it and install a fitting.

[bracurrie]

Shvegel - Thanks for the suggestion.

Does anyone know what the Y means on the pump designation? R20Y for example.

[Pawel66]

US versions?

https://www.sl113.org/wiki/Fuel/Injection

[bracurrie]

I think you are right Pawel66, except I believe its the fuel shutoff solenoid specifically.

[mauro12]

Guys , I have a similar situation. My 250 sl has the r22 injection pump . I’ve been told from oldtimer technik ( Hans fritzsche) that the best solution for my car is to install a 3D space cam of the r18 pump in my r22. Doing this will bring the benefit of a more modern pump and have the right calibration for the 250SL . Is very expensive to have it 3D printed , but it will solve the problem for other 50 years or more . Also I realized that Hans fritzsche uses a different kind of bench test with frequency inverter technology. I don’t know exactly what is about , perhaps is more precise than a standard bench test .

[Shvegel]

Mauro12,
There has to be a space cam out there somewhere.  Quite a few junk pumps in the world.

[mauro12]

You are right , but probably the cost of a spare space cam from another pump is almost the same of the 3D printing . Is about 300-400€.

[DaveB]

Mauro I might have the part you need. The pump it's in is R18Z, from a 250SE. I don't know whether this differs from the SL version. You can have it for postage cost.
I'm assuming it can be extracted without special tools.

[mauro12]

Hi, I’m interested . I wrote you in private .
Thank you

[DaveB]

Can anyone please advise how to extract this space cam undamaged?
It looks like it might slide off backwards if I can remove the governor assembly but I can't see how to do that.

[DaveB]

I removed a bit more - is that a slotted nut in there?

[Shvegel]

Slotted nut then a special puller to pull the fly weight assy.  Since you are not trying to save the fly weight assy any puller will probably do just hook it in the tombstone shaped slots on either side of the flyweight hub. 

[DaveB]

Thanks Pat.
Unfortunately though Mauro, the part looks heavily worn and I think it's trash.

[Tyler S]

That cam actually doesn’t look that bad. They all look like they are grooved out but they are machined this way and is part of the fuel map. You won’t know for sure until you test it in a pump though. R18y pumps tend to get accelerated wear in the idle circuit/map area of the cam because of the fuel cut solenoid constantly slamming the stylus onto it. A R18z does not have this problem because of the lack of the fuel cut system. It may be ok.

[DaveB]

Ok, interesting, maybe it will work after all. Mauro's going to ask his rebuilder.
It's a complicated part! I have no idea how a surface like that could be machined in the mid 20th century. 3D printing seems simple in comparison, conceptually at least.

[Shvegel]

They’re made by elves on Mushrooms.

[Tyler S]

They would have been made on a part copier. Similar to the way a key is reproduced. A master part is tracked with a stylus and a cutting implement fixed on a shaft would remove material to match.

[DaveB]

They would have been made on a part copier. Similar to the way a key is reproduced. A master part is tracked with a stylus and a cutting implement fixed on a shaft would remove material to match.

Thanks, yes that was how I was thinking it would be done. Elves only had to make the prototype.
Your assessment of the space cam was correct, deemed usable by the pump rebuilder.

[DaveB]

I guess the original could have been machined with spherical die grinders of different sizes. With a lot of trials involved in developing the final profile.

[mauro12]

I really have to thank Dave because this space cam was in perfect condition and not worn out . This is the shape that should be . At the beginning I thought that was worn out but I was wrong . Thank you very much for your support !