So I don't have the part numbers off hand but there are 2 different style lift pumps used on w123's. There is an early version that can't be rebuilt then a later style that we all know and can be rebuilt. I bought a spare one at pnp the newer style. I was wondering if anyone knows if the specifications of both are the same or is one say the newer style better? I figure there must have been a reason for Mercedes to change them but I can't find or figure why?

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i know my 74 240D has a lift pump with 2 bolts . where as the 79 i had had 3 bolts on the lift pump ... so there maybe be more than just 2 types ,

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current fleet
Ford f350 dully 7.3L 1990 . ats turbo , zf5
Mazda 4x4 b2600 with 617 20-26 mpg
Past fleet
1983 240D w123 232k 25-30 MPG
1984 Ford f250,1979 ford 150 300-6 (sold@ 251K )
81 300D, 79 240D , 2x 76 300D ,74 240D , 2x 89 grand prix , 85 grand fury , and several other fords

Custom machine shop work ..

It is highly doubtful that your 1974 240D was a W123.

Here's a pic I umm borrowed from someones thread....this is the early style that is on my car.



And of course this is one we see on all the other w123's



What's funny is I pulled the newer style lift pump off a 78 300sd and mine is a 78 300d but has the older style..

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The Photo of the Old Lift Pump is good but not good enough to read that little number Plate that is on it.
Copy down those Numbers and take the Numbers to a Bosch Shop (or call them) and see if they make a Rebuild Kit for it.
Or do the same with the Plican Parts guy.

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84 300D, 82 Volvo 244Gl Diesel

I think the change may have had to do with the turbo. I believe the NA diesels use on type and the turbo diesels use another.. could be wrong though...

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2004 F150 4.6L -My Daily
2007 Volvo XC70 -Wife's Daily
1998 Ford F150 -Rear ended
1989 J-spec 420SEL -passed onto its new keeper
1982 BMW 733i -fixed and traded for the 420SEL
2003 Volvo V70 5 Speed -scrapped
1997 E290 Turbo Diesel Wagon -traded for above
1992 BMW 525i -traded in
1990 Silver 300TE -hated the M103
1985 Grey 380SE Diesel Conversion, 2.47 rear end, ABS -Sold, really should have kept this one
1979 Silver 300D "The Silver Slug" -Sold

That's what I was curious about, and I was wondering if adding the Turbo type/newer style might increase power?

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Assuming that the newer version could flow more (which I have no idea if it does or not) it wouldn't increase power unless your existing one was already not putting out enough at the correct pressure. The injection pump puts out metered amount with each stroke of an element. Without increasing the size of the elements (and thus the amount of fuel delivered) no more power can be made. This is a moot point however since you have the non turbo version of the car, so even if you tuned the pump for more fuel, it wouldn't burn it because of lack of air.

Best thing to do if you want the maximum your engine can give is to check timing chain stretch and compensate for it with a woodruff key on the cam if necessary, make sure your pump timing is correct, and have the injectors tested for patter/flow/balence (odds are by this point they need rebuilding)

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2004 F150 4.6L -My Daily
2007 Volvo XC70 -Wife's Daily
1998 Ford F150 -Rear ended
1989 J-spec 420SEL -passed onto its new keeper
1982 BMW 733i -fixed and traded for the 420SEL
2003 Volvo V70 5 Speed -scrapped
1997 E290 Turbo Diesel Wagon -traded for above
1992 BMW 525i -traded in
1990 Silver 300TE -hated the M103
1985 Grey 380SE Diesel Conversion, 2.47 rear end, ABS -Sold, really should have kept this one
1979 Silver 300D "The Silver Slug" -Sold

Not if the Old One is working correctly.
I say that because only a tiny amount of the Fuel From the Fuel Supply/Lift Pump ends up Injected into the Engine. Most of the Fuel is used to cool the Fuel Injection Pump Housing and returned to the Fuel tank.

A problem with the Fuel Pressure Relief/Overflow Valve is more likely to have an effect on the performance.
Long Fuel Pressure Relief Valve/Overflow Valve Thread
http://www.peachparts.com/shopforum/showthread.php?t=234609

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84 300D, 82 Volvo 244Gl Diesel

NO, it will not add power unless your valves MB# 0000900210 are bad.
A damaged or mis-adjusted fuel bypass valve will make a good lift pump waste pressure.

Fuel injection pump starvation with a good lift pump
Fuel injection pump starvation with a good lift pump - PeachParts Mercedes ShopForum

Fuel pressure relief valve adjustment
Fuel pressure relief valve adjustment - PeachParts Mercedes ShopForum

lift pump test
1979 300td -- Can anybody walk me through a lift pump test? - PeachParts Mercedes ShopForum

fuel pressure
fuel pressure - PeachParts Mercedes ShopForum

Up to a point:
Mechanical injection Diesel Power is a function of increased fuel = altitude compensation device, delivery valve bore, injector, and internal governor adjustment.
This assumes compression and timing are good.

.

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1985 300SD
1983 300D
2003 Volvo V70

https://www.boldegoist.com/

I've got some non-turbo lift pump related information here (mostly about the pump fitted to my M/RSF IP)

Refreshing the fuel pump on an OM617 (European spec – non turbo)

This might help

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!