Clouds of grey smoke, need help - PeachParts Mercedes-Benz Forum

BathCity · #1 05-23-2008, 07:04 PM

I have been searching/reading all week since my purchase of the '74 240D. I bought the car last Saturday and had it toted home. The car was not in running condition when I got it.
I have the injection pump installed & timed to the "Banjo nut blow" method, I have adjusted the valves to spec, checked the timing chain stretch, looks to be 2 to 3 degrees, cleaned the oil catcher at the end of the blow by tube, I pulled the injector, there were not any heat shields, installed the heat shields and reinstalled the injectors, checked the vacuum governor operation by removing the line from the butterfly valve, the engine speeds up considerable with it off. Installed new fuel filters (both) and changed the oil (lovely experience). I drover her last evening and she seems to drive well, love the ride versus my Volvo 240D. Auto trans shifts seems to shift properly (takes off from light in 2nd with moderate pedal)
Here is my problem; I have PRODIGOUS amounts of gray smoke coming from the engine. I have read many things here while searching the forum but have yet to eliminate the gray smoke, could anyone of you give me some more pointers to look for?

Jeremy5848 · #2 05-23-2008, 07:12 PM

Smoke from the engine meaning spilled oil burning off? or smoke from the exhaust, meaning oil getting into the cylinders and being burned there?

Jeremy

BathCity · #3 05-23-2008, 07:15 PM

Gray smoke from the tailpipe.

cg487 · #4 05-23-2008, 07:25 PM

Quote:

Originally Posted by BathCity

Gray smoke from the tailpipe.

I would not be paranoid about this yet since cars that have been sitting for a long time will do this until they get a few miles on them. Gray smoke could be burning oil, but again sitting doesn't make any vehicle get better with age!

It really depends on how long this lasts and how much oil your consuming, and this is thinking your timing is set properly, which would also cause this, but at a loss of horsepower.

WTH is a "banjo nut blow" Method?? Never heard of this!

bgkast · #5 05-23-2008, 07:29 PM

I'm not familiar with the "banjo nut blow" method of timing, but you might want to double check the IP timing using the "drip" method.

Here are some other things I would check or try in no particular order: Italian tune up, Air filter, injector pop-pressure and spray pattern, compression.

Jeremy5848 · #6 05-23-2008, 07:33 PM

Does the gray smoke smell like oil? As cg487 says, cars that have been sitting will smoke for awhile. Drive the car normally, watching the oil level carefully. Record any oil that you add so you'll know how much it is using. Try to put on a thousand miles, both around town and freeway trips, before making any decisions. If after a couple of hundred miles the engine is not significantly down on oil, try an "Italian tuneup." The engine may clean itself up if you give it a chance.

Jeremy

BathCity · #7 05-23-2008, 08:20 PM

The "banjo nut blow" method of timing I found on this form. It said to replace the return line banjo fitting with one that has the check removed with a hose attached. Said to set timing of pump in relation to just when the air stops coming out of the #1 injector fitting (with vale removed) and then lock it there.
It doesn't smell like oil. Come to think of it, it looks like the smoke puff I get from my 240 Volvo diesel wagon when I start it after it has run. Only in prodigious amounts, clouds.
I'll have to take it for the "Italian tune up" tomorrow after I get the motor mounts in. (They are collapsed)
My worry is that the injector pintles have been damaged by the lack of heat shields from the PO I got it from.

wis · #8 05-23-2008, 08:29 PM

double check pump timing. also if i remeber correctly the 616 has two crank keys and the balancer can go on either way. the engine will run with the pump 180 out and it will smoke like crazy....ask me how i know...anyway i would suspect pump timing if it was me.

BathCity · #9 05-23-2008, 08:38 PM

so if it's 180 out as you say an still able to run, should I then remove the pump, rotate the shaft 1 turn to the set point again, then re-install it?

bgkast · #10 05-24-2008, 01:53 AM

You would have no power if it were off 180* I think.

Cervan · #11 05-24-2008, 05:50 AM

180 off means your injecting fuel on the exhaust cycle. it will run, but will have horrible top end power and blow tons of smoke. Blue means oil, white means unburnt diesel or coolant, and black means partially burnt diesel. I suggest an Italian tune up with an oil change and all that PM stuff, with adjusting the valves should clear this up.

winmutt · #12 05-24-2008, 07:52 AM

Use the proper method for timing, the drip method. Grey smoke means preignition.

Stevo · #13 05-24-2008, 09:55 AM

Quote:

Originally Posted by BathCity

so if it's 180 out as you say an still able to run, should I then remove the pump, rotate the shaft 1 turn to the set point again, then re-install it?

Does your engine run as described for having the IP 180 degrees out? If so lets say you have the IP out and the marks on the cam and balancer are lined up. The engine would be rotated till # 1 is at 24 degrees before top dead center of the COMPRESSION stroke and the IP installed with its marks lined up. You would know the compression stroke because the cam lobes of # 1 would be pointing upwards and the cam mark would be approaching the mark. The bubble method is a proper way to time your IP regardless of what those that haven't tried it say

Cervan · #14 05-24-2008, 10:19 AM

Quote:

Originally Posted by Stevo

Does your engine run as described for having the IP 180 degrees out? If so lets say you have the IP out and the marks on the cam and balancer are lined up. The engine would be rotated till # 1 is at 24 degrees before top dead center of the COMPRESSION stroke and the IP installed with its marks lined up. You would know the compression stroke because the cam lobes of # 1 would be pointing upwards and the cam mark would be approaching the mark. The bubble method is a proper way to time your IP regardless of what those that haven't tried it say

how about the TAE method? Trial and error

Thats what i usually do, i advanced it just until it started knocking, and then i backed off in tiny increments until tada its timed.

Stevo · #15 05-24-2008, 10:45 AM

Quote:

Originally Posted by Cervan

how about the TAE method? Trial and error

Thats what i usually do, i advanced it just until it started knocking, and then i backed off in tiny increments until tada its timed.

A good friend/shop owner told me that sometimes when he has a diesel MB that hes done work on, he will bump the IP (advance) just a skosh and in most cases it will run better, if not he puts it back where it was. He said the owner is usually impressed with how much better the car runs.