I've been helping my friend get her 1979 300d wagon back on the road. Adjusted valves, tested and removed bad glow plugs. My plan was to get it started, run a few gallons of diesel through it, then do a diesel purge. Next, pull the injectors and put in a set that I have cleaned and balanced.

A few problems though. The engine is turning over very slow. I connected my running 240d to it with cables, and still cranked very slow. I even pulled my battery and installed it into the 300d, still very slow crank.

I took a closer look at the compression test (and realized it was taken four years ago! Last time the car ran). I knew it had 2 low compression cylinders, but I learned that they are side by side. Cyl 4 and cyl 5 are really low, right around 200. The first three are all close to 400. Am I right to assume that the head gasket is bad between the 4th and 5th cylinders?

And what about the slow crank?

I am going to pull the first injector today and visually check to see if the 1st glow plug is lighting up. The car still has the old linear loop plugs.

I'm really starting to think it might be a lost project.

I wouldnt bother chasing the GP's. There is a strong possibility that the motor has a blown head gasket. pull the head & have a look.
The second possibility is broken rings. When you have the head off you can check the bores for damage.

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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

sounds to me like you also have a tired starter, or a wiring connection problem. Try tapping on the starter with a hammer just in case its full of rust, or ice depending on the climate.

See if it speeds up when you do that, might be time for another.

Id start with the slow crank as a blatant problem, that could definitely add to any starting issues.

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You might save some effort by injecting air into one cylinder and seeing if it comes out into the second cylinder with the injector removed. Or doing a compression check again on those two cylinders to see if the pressure is identical is almost certain proof the head gasket is breached between the two bores.

Not too bad a job but it is always nice to be certain of what you are going inside an engine for.

Do a leak-down test. If air is getting between two cylinders, you should be able to hear it escaping from the other glow-plug or injector hole (whichever you're using).

You do not actually need the Leak Down Tester just to listen for the air leak. Just a sorce of compressed air and an adapter to hook the pressurized air to the Engine. Like the adapter you used to take the compression.

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84 300D, 82 Volvo 244Gl Diesel

Thanks guys. I'm going to clean the connection points on the starter, make sure it's getting all the juice that it needs. I've never "beaten" on a starter before, but now's my chance! ha. I do have a spare starter that I'll throw on there is the current one still seems shot. The owner told me that it took a long time for the car to start, back when it did start. The second glow plug was bad, so it only had one working, on the #5 cyl. So I'm thinking the owner wore out the starter.

I like the compressed air ideas. I'll get on that as well.

Be sure to clean the whole circuit... the ground points are just as important as the positive connections...
Be careful about air into the cylinders... read the cautions on leak down tests... those cylinders will not both be at BDC ...so the engine will likely turn with no warning unless you lock it in place somehow... and the clutch or parking pawl may not be strong enough to do that... proper procedure is to lock it with tool at the flywheel... no need accidentally losing any skin or finger tips..

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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