Fuel Injection Pump

[Sens]

Hello there,

I have a 250SL from 1967.
The engine has been replaced in the past by a 280 SE/SL engine of a W108.

When I look at my FIP I see the number PES6KL 70A120 R18z and serial number 0408 026 015.
It looks like it is the original FIP of the 250SL mounted on an 280SL engine. The letter A indicates that the pump is for a 250SL; for the 280SL it should have been a B.

So far I never had a problem and the engine runs great, but is this combination something to worry about??

Thanks,

Halvor

[ja17]

Does your R18z injection pump have the red oil fill cap and dip stick?

[Sens]

Hi Joe,

Thanks again for all your help!!!

The FIP has a blue oil cap and I believe no dip stick.

Looking at the oil line, I believe it is the earlier type, for a 250 SL.

Halvor

[Sens]

Could this FIP work well on a M130 engine block?

[rwmastel]

I have a 250SL from 1967.
The engine has been replaced in the past by a 280 SE/SL engine of a W108.

Could this FIP work well on a M130 engine block?

Halvor,
From what you say above, isn't it already on an M130 engine?  Or, maybe the engine is not running so you don't know if it works?

[Sens]

Yes indeed, it is mounted on an M130 engine and it runs fine!

I just wanted to know if this combination will give problems in the future.

[Sens]

I was just wondering whether I should leave the 250SL FIP on the 280 engine or should I try to change it for an 280SL version.

Does the 250SL FIP give less fuel than the 280SL version?

[Kevkeller]

If it works why change it?

[MikeSimon]

If it works why change it?

"works" is a stretchable term. Unless it works well under a variety of conditions and for a long time, it doesn't mean much.

[Sens]

It works well, but maybe a 280SL FIP works better.

Is the amount of injected fuel the same?

[Sens]

Hello,

Would a FIP from a 280SE be a better combination with a 280SL engine than my current 250SL FIP?

Any advise?

[ja17]

Early IP pumps had a oil supply which was separate from the engine oil. in addition, they did have an oil line from the engine which under pressure supplied engine oil to the plungers in the injection pump. These early iP pumps had a dip stick and a oil supply line with a check valve.  They also had a red filler cap to replenish the oil in the IP when it was changed. Oil in the IP was isolated from the engine oil and had to be changed and level maintained. Later pumps used continually circulating oil under pressure from the engine. No dipstick was needed. The entrance into the IP was in different places on the back side of the pump (Go to the Injection Pump tour for pictures and discussion of both). Since engine oil circulated through these later pumps, the oil automatically refreshed during an engine oil change service and no dip stick or filler cap was required. I do not see any reason why the 250 pump cannot be adjusted to work on the M130 as long as it's oil circulation is correct. Make sure the oil line is connected to the correct place on the IP. No check valve in the oil supply line to the IP is needed on the M130 although some of the early engines did have one.

[Sens]

Thanks a lot Joe for your answer!!
I have the "older" version, with the higher oil line connection. however in the meantime all pumps are "old".

[mauro12]

I have a 280sl pump on my 250sl , was working but a bit on the rich side .
I decided to send for a complete overhaul and calibration and they tuned the pump accordingly to the 250sl specifications.
In addition they also replaced the space cam of the pump which is different for each model . The biggest difference is the 230sl pump which is more difficult to tune for a 250 and 280 car .
The car is running very smooth . Probably I have to lower to co% because is about 7%.
The injectors have a bit low opening pressure and perhaps this is the reason .

[Sens]

Thanks your reply!

I think I will use the 250SL pump first.
I had a CO % of 4%; which is OK, I believe.

[mauro12]

Yea you have to have the right balance between co and HC .
These cars are happier with more fuel than normal . You must have good compression and good injectors to reach the perfect combination . I should replace the injectors to have the best performance but I’ve experienced very bad outcome with r2 injectors .