I would love to find a completely rebuilt 722.118 transmission just to "drop in" to give this car another lease on life. Surely, they must be out there but it seems like an uncommon model as it was in a transition period I think.
Either that or just go all the way and put a manual in there. In that case, is there a close-ratio 5 speed that would help the engine really work within its optimum power band?
This is all mere conjecture right now since I'm nearly flat broke after a burglar broke in to my apartment last week and stole all my digital camera gear that I used for a good part of my income. Now I just have a part time retail job at a rather well known chain of home improvement stores but that's not going to cut it for too long. So at this point, I'm just trying to keep the car running in as good of condition and tune as I can.

Phil Forrest

__________________
1972 220D "Trudy," named by a friend.

"The 220D sounds good... I suspect it is the only car that you need a calendar for, rather than a stopwatch, when doing acceleration tests."
Tom Abrahamsson

Could my nailing be due to fuel delivery?
I have what I think is the original lift pump with the original push/pull type primer pump and I've read these both will suffer with age and if one of the diaphragms in the pump is getting stiff or corroded perhaps this is my nailing issue.
I ask because the nailing usually occurs only on accelleration at high RPM, right before a shift. If I'm driving at high RPM on the highway (about 65+) the nailing ceases like the pump has caught up with itself.
Any thoughts on this?

Phil Forrest

__________________
1972 220D "Trudy," named by a friend.

"The 220D sounds good... I suspect it is the only car that you need a calendar for, rather than a stopwatch, when doing acceleration tests."
Tom Abrahamsson

It is very possible.


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

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You may also need the first item here.
REPAIR KIT
MB# 0000900210
OM617.951 and .952 Lift pump Repair kit W126.120 300SD W123.133 300D

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Be aware; If the fuel tank vent valve or line is plugged, you can get the same symptoms due to vacuum

Fuel tank vent pictures + location
93 300D 2.5L Turbodiesel Power Loss

What happens when a tank vent gets clogged.
What happens when a tank vent gets clogged. - PeachParts Mercedes ShopForum

Imploded fuel tank - so sad!
Imploded fuel tank - so sad!

Why do I have vacuum in my diesel tank.....................?
Why do I have vacuum in my diesel tank.....................? - PeachParts Mercedes ShopForum



.

__________________
ASE Master Mechanic
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Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
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Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

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So I can easily rule out a clogged tank vent by running the engine without the filler cap and listening for nailing then, correct? That would be an incredibly simple repair and with my luck, not the culprit.

For the pressure relief valve, I'm going to have to find some space to work on the car since I can't do that job in the street.

I don't have any loss of power with the nailing. It's intermittent and only at a relatively narrow place in the RPM band. I wish I had a tachometer instead of a clock but that is not to be on this engine. I might fashion one up using a bicycle cadence/speedometer sending unit and a small magnet with a wired pickup.

Before I get into the pressure relief valve, I'm going to make sure the system is clean. Since I switched to B20 (for most of my last fuel-ups) the engine runs soother but I still get nailing. I've done a few purges and every time I change the filter, I can see grains of black "sand" dump out of it. I think that I've got a problem with dirty junk in the system. I know I really need to take the screen out of the tank because I can garantee it's got some serious crud in there.
Last October I pulled the fuel level sender and it had about 3/4 inch of crud just caked on and the low fuel level light wouldn't come on. After cleaning it, the thing works perfectly but I think that the old sludge plus the recent B20 tanks have probably shined up the inside of that tank really well and could be starving my pump from the screen.

So like I said, I'm going to make sure everything is clean before going for the pressure relief valve and the injectors. Not that I wouldn't love a set of injectors with fresh nozzles... Perhaps that could be the route I take. I've got a bit of money to put into the car right now and swapping injectors/heat shields can't be too difficult that it would put my car OOC for more than two days.

Phil Forrest

__________________
1972 220D "Trudy," named by a friend.

"The 220D sounds good... I suspect it is the only car that you need a calendar for, rather than a stopwatch, when doing acceleration tests."
Tom Abrahamsson