Hello Y'all,

I adjusted the valves on my sweet baby this morning and she does run smoother and seems to have a little more power but she is still hard to start. Compression would be my uneducated guess.

Quick Dumb Questions:
1. How do I perform an audible leakdown test? What do I listen
for?

2. What valve work can I do with the cylinder head still on the
block? I.E.- seals? guides?

3. If TDC mark on camshaft lines up with the mark on the cam
tower and the TDC mark on the balancer lines up with the
pointer would this mean that the timing chain is not stretched?

4. Why did I buy this '82 240D?

Sounds like the chain is in pretty good shape. If it is not using oil I would not think there are any issues with the rings or valve seals. How many miles are on the car? I would look at the glow plugs first for hard start issues, especially considering it good once up to temp.

__________________
Jim

Oilslick:

Does the glowplug lamp work correctly (ie comes on for a while, then goes out and stays out)? If not, you have at least one bad glowplug.

Easy check is to check for 12V on each glowplug while operating, and to check the resistance of all four (you can pull the plug off the relay to check resistance).

If the glowplugs check out, and the valves are OK, time for the leakdown

To perform, you need to pull either the injectors or glowplugs, then add compressed air to the cylinder AT TDC FOR THAT CYLINDER. You must be at exactly TDC with both valves closed. Close won't work, the engine will motor to BDC and a valve will open!

Hiss in the intake, intake valve leaking. Hiss in the exhause, exhaust valve leaking. Hiss in the crankcase, rings.

I would advise against adding oil and repeating a compression test to check for worn rings -- it is possible for the oil to ignite, and this will blow up the compression gauge, usually.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

1 qt. every 400 to 500 miles! I am just not wanting to face the facts I guess. I hate the term "low compression"!!! I know that my baby has blow-by but can't a man cling to hope?

The MB service man checked the GP's and said that they seemed to be fine.

She doesn't smoke continuously, only when I put my foot to the floor. There is some blue smoke on initial start-up but that goes away after a minute or two. Some oil is escaping around the cam cover nuts. The valve adjust that I performed DID seem to help the gal. Maybe I didn't get the valves "gapped" correctly. I guess that I'll just crank her till she "catches" and drive the "pookey" out of her.

psfred

What kind of pressure should the cylinder hold? This sounds easy compared to a compression test. I think they used to this on aircraft engines because it is more accurate. I might be at that point to try and determine if I have leaky cylinders.


PeterG



79 300 SD

My 240d became really hard to start in the AM. I usually had to heat them up, turn off the key and then heat them again before it would start.

Glow plugs seemed to test OK so did not change them for a while and figured that something else must be wrong.

Then, one Saturday, I did change them and it now starts immediately. Had a new set on hand that had been in a drawer for a few years.

Cannot figure out why the old ones tested OK though because at least one must have been bad.

They are so cheap, they are worth changing if you haven't done it for a while. Mine had been in for 10 years or so I think.

Are you doing the one minute GP burn like I recommended the other day ?

On the head you can only do the seals as far as I know.....

Be very careful applying AIR PRESSURE TO ANY CYLINDER... It can hurt you... If you don't have some positive way... meaning bolts... to lock the crankshaft I recommend you NOT put air to the cylinder... UNLESS YOU DO IT AT BOTTOM DEAD CENTER... There is the risk of it turning the engine otherwise..
VW had a Crank Lock available... it would bolt onto the flywheel ring gear... very handy and safe....
I think some other people on this forum have gotten bad indicators of the condition of the chain using the method you describe.. I don't understand why....still a mystery ... but when you get the manual ... or do a search for JimSmith's description of checking chain stretch... The Factory shop manual says to check the chain elongation by another method... very simple .....

Compression should be at least 300 psi -- you will need a DIESEL compression gauge, a gas engine gauge can fail and blow up in your face, to say nothing of not reading high enough...

new compression is about 400 psi.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Hey Friend,

I tried the "extra" glow time. No real results on my stone cold engine. One obstacle that may have hindered the success of the "extra" glow time was that I forgot to hook up the idle cable after doing the valve adjust. She wouldn't start so I kept cranking, and cranking, and cranking. I almost had her going and then realized that the cable was not connected. After I connected the cable she fired up! I will try a cold start in the morning and maybe, with the idle cable functioning properly, she will start somewhat easier.