Author Topic: 230SL Injection Pump Oil  (Read 6221 times)

Tomnistuff

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230SL Injection Pump Oil
« on: September 06, 2017, 01:07:59 »
I've read, I think, everything written here and in the TM about the 230SL R11 Injection Pump and in particular about the oil system.  I'm pretty confused and not very confident that I know what I'm doing.

I would like to verify the info about the fill and extraction locations and if possible get a "firm" fill quantity required to put in a rebuilt "clean" Injection Pump already on the engine.

I found the dipstick, and its location is OK for measuring, but it's not easy to get to for filling without making a mess of my garage floor and engine compartment.

I also found the red oil "vent" cap, which is quite a bit easier to use for filling "IF" it is an acceptable oil fill location.

The "vent" cap has a second advantage of allowing the fill oil level to rise from the bottom of the dipstick, rather than the oil flowing in from the dipstick hole opening, thereby avoiding the problem of getting oil all over the dipstick as it is inserted and retracted from the oily dipstick hole if that hole is used for filling.

Is the vent cap hole a valid fill point?

The quantity is not really an issue.  Since the IP is clean, I will determine an accurate quantity of clean, fresh oil that corresponds to the fill line on the dipstick. 

I'll be back here to post the results.

All I really need to know is, "Is the red oil vent cap with "OEL" written on it an acceptable fill location?

Since people seem to have problems finding the dipstick when the IP is in the car, I've posted photos of it and the OEL vent cap.  You might have to scroll to the right to see the dipstick hole when the photos are enlarged.

Tom Kizer
Apparently late 1966 230SL 4-spd manual (Italian Version)
Owned since 1987 and wrapping up a full rotisserie restoration/modernization.
Was: Papyrus White 717G with Turquoise MBtex 112 and Kinderseat
Is: Dark Blue 332G with Dark Blue Leather (5300, I think)

Jowe

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Re: 230SL Injection Pump Oil
« Reply #1 on: September 06, 2017, 04:44:14 »
"Is the red oil vent cap with "OEL" written on it an acceptable fill location?

The answer is: YES
Johan
04/1964 230SL, European, manual 4-sp, power steering, 050/050 white, black leather, Blaupunkt (SOLD)

Paul & Dolly

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Re: 230SL Injection Pump Oil
« Reply #2 on: September 06, 2017, 07:37:08 »
Hi Tom,

Checking / altering the oil level is not so easy, so I use a syringe to add/remove ,and a cable tie to check the level, it saves fiddling about screwing/unscrewing the dip stick, which I find very hard to read accuratly with clean oil, the cable tie is much easier.
(N.B. Compare a cable tie with your own dipstick, and measure down from the stop, not up from the bottom)
Hope this helps

Paul
« Last Edit: September 06, 2017, 07:44:36 by paladin »
Paul (located in Cardiff - Wales - UK)
1967 Early 250 SL (Auto) White
Mitsubishi i Car
Toyota RAV 4  Hybrid AWD
1936 Alvis Firebird (Gone............)

Tomnistuff

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Re: 230SL Injection Pump Oil
« Reply #3 on: September 06, 2017, 13:40:04 »
Jowe and Paladin,
Thank you both for your rapid and clear responses.
I'll fill it today and report back with the amount it took for my "clean" IP as well as my impression of the experience.
Thanks again.
Tom Kizer
Apparently late 1966 230SL 4-spd manual (Italian Version)
Owned since 1987 and wrapping up a full rotisserie restoration/modernization.
Was: Papyrus White 717G with Turquoise MBtex 112 and Kinderseat
Is: Dark Blue 332G with Dark Blue Leather (5300, I think)

Tomnistuff

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Re: 230SL Injection Pump Oil
« Reply #4 on: September 07, 2017, 00:41:26 »
Jowe, the OEL cap is not only a valid fill point, it's really easy and clean to use with a syringe.

Paladin, I followed your suggestions to the letter, using a 10 ml syringe for accuracy and a black plastic tie-wrap (notched on the shiny side) for visibility.  You were kind when describing the difficulty of using the bronze pin dipstick.  I would call it useless as a dipstick.  I was finally able to read it after laying it full mark down on a paper towel and rolling it 1/2 turn to visually compare the full mark with the end of the oil stain on the white paper towel.

The tie-wrap duplicates the function of the dipstick perfectly, total length and full mark location from the tie-wrap "ratchet", designed so that the ratchet part fits into the hole and always stops in the exact correct place.  See the first photo.

After filling to 100 ml, the dipstick (tie-wrap) had 3 mm of oil on the tip which was 12.5 mm from the full mark.  See the second photo.

After filling to 150 ml, the dipstick had 10.5 mm of oil on the tip which was 5 mm from the full mark.  See the third photo.

After filling to 170 ml, the dipstick had 15.5 mm of oil on the tip which was exactly at the full mark.  See the fourth photo.

Conclusions: 
1)  Since the 50 ml volume change from the first to second
measurement changed the level by 7.5 mm (1.5 mm per 10 ml of
fluid), and the 20 ml volume change from the second to third
measurement changed the level by 5 mm (2.5 mm per 10 ml of
fluid), the conclusion is that the level change vs volume change is far
from linear.  Surprise, surprise!  The geometry of the inside of the
injection pump is very complex.
2)  Since the total oil introduced to this clean and dry injection pump
was only 170 ml to reach the dipstick "Full Mark", and many posters
indicate that the pump requires from 200 to 250 ml, I conclude that
there are volumes in the pump that are still currently dry and will
receive and trap oil from the reservoir once it is run and that, like
the engine, it must be topped off after it has been primed or at least
after it has been started and run for the first time after a rebuild.

After priming the engine and injection pump, I'll let them rest a while then I'll recheck the level in the pump and measure the amount to be added to get back to the full mark, if any.  Then I'll come back here to post the results.

You may have to scroll to the right to see the tie-wrap dipstick in the first photo.
I don't know why.

Tom Kizer
Levis, Quebec, Canada
« Last Edit: September 07, 2017, 00:47:00 by Tomnistuff »
Apparently late 1966 230SL 4-spd manual (Italian Version)
Owned since 1987 and wrapping up a full rotisserie restoration/modernization.
Was: Papyrus White 717G with Turquoise MBtex 112 and Kinderseat
Is: Dark Blue 332G with Dark Blue Leather (5300, I think)

Paul & Dolly

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Re: 230SL Injection Pump Oil
« Reply #5 on: September 07, 2017, 07:00:55 »
Hi Tom,

Thanks for the update, and I am glad you found my "kit" helpful, I also had to resort to trying to read the oil level on a paper towel, hence the cable tie.

It may be nice to add your experience here to te WiKi, I had meant to do it, but other stuff seems to get in the way.

I currently revisiting my "heater" air scoop flap to clean out the drains,again,and try and reaffix a metal flap that has partially come loose and rattles.

Keep well

Paul
Paul (located in Cardiff - Wales - UK)
1967 Early 250 SL (Auto) White
Mitsubishi i Car
Toyota RAV 4  Hybrid AWD
1936 Alvis Firebird (Gone............)