Hi,

I have a 1984 G-Wagen (ground up resto) with a swapped in OM617A from a car that lived in a field near the end of its life. With 480,000km (300,000 miles) on the clock and being thoroughly ignored it had all the usual problems- leaking oil, lots of smoke, poor starts, wouldn't stop, etc.

I actually thought it would be a "temporary" motor because of the high mileage, but now its running great, starts easily (even well below freezing), slight blowby, and with some engineering now stops without incident. I'd like to perform all the "wear" work on the motor so it just keeps running. I'm assuming that if I maintain this motor I could get another 400,000km without a rebuild.

There are only three problems I have at the moment. 1) Light smoke at idle and 2) low power on the freeway (can't maintain 60mph on hills) and 3) high fuel consumption (about 14mpg, I'm expecting 20mpg from prior experience). The G does weigh a lot more than say a 300D, but I know I can get more out of this motor.

So far, I've done the following:

- new GP's
- new gaskets at oil pan, valve cover, oil filter housing
- valve adjustment
- diesel purge (twice)

I'm considering, in rough order:

- injector rebuild
- timing adjustment
- timing chain
- vacuum pump

Does anybody have other thoughts, based on my goals of keeping this motor running for several more years + giving me the slight performance boost over what I see now?

Cheers,

Michael

An injector rebuild may be a good start. A timing adjustment with the mileage you mention would only be a band aid fix without the chain being replaced.

__________________
DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012

If there is any chance it needs a new chain .. that is a relatively cheap insurance policy. Be sure to replace all things which touch that chain if you can.. tensioners, rails, etc.. sprockets if you are able...
Then set the timing by the correct method.... the position of the number one valve...
that is cheap and will give you a baseline for the rest of the improvements.
I would do just one operation at a time....then you can tell what it was that made a difference.

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/diesel-discussion/10414-help-i-need-check-stretch.html

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

ALDA cleaning?
Linkage hitting full stop?
Compression test.
Clean/poptest injectors.

__________________
http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

If your top speed is 60 MPH, sounds like it is starving for fuel. Have you replaced the fuel filters?

Also be sure to check for full travel of the linkage from the accelerator pedal.... many a person on the forum has ' discovered' 20 mph more top speed just from that system...

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

The W123 rubber throttle bushing can easily cause the lack of full throttle travel due to its design and failure when it wears out. The W126's are not as likely to have throttle travel issues.

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

Is this a turbo or N/A motor?
I got 800k miles out of a N/A but in the end it was very sick. The motor had been properly maintained from new. I wish you luck with you dream of another 400k miles! If i were you I would consider a low mileage second hand motor if you are short on cash. It sounds like you have a nice G with a motor thats close to its use by date.

__________________
Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving

He's talking kilometers, not miles. Note that he's a fellow Brit from Canada (Canadians and Australians are all Brits, aren't they? :-0 ) and they went metric long ago.

Frozen rings might lead to the blowby. Folks have had success running water injection to loosen the rings, but it's not trivial. Check compression. And plan to replace the engine at some point. If you're not getting velocity or mileage it may be the most expedient path.

__________________
mjk

'84 300SD 119KMi (Liesl der Diesel)
'84 300D 326KMi when the oil left (former parts car)
'82 300SD 253KMi (new parts car)