82 300SD Excessive Blowby - PeachParts Mercedes-Benz Forum

richclay · #1 01-07-2006, 03:07 PM

What is the general reason for excessive blow by on a 82 300SD?

TheDon · #2 01-07-2006, 03:09 PM

a diesel engine showing its getting old.. really old and not taken for .. time to collect social security for that engine . how bad is the blow by?

does the oil cap fly off and hit stuff like your head?

Hatterasguy · #3 01-07-2006, 03:11 PM

Age and time. More importantly how does it start cold? When it becomes hard to start its rebuild time.

biopete · #4 01-07-2006, 04:21 PM

Quote:

Originally Posted by TheDon

a diesel engine showing its getting old.. really old and not taken for .. time to collect social security for that engine . how bad is the blow by?

does the oil cap fly off and hit stuff like your head?

Just what is "Excessive" Blow by anyway? My oil cap does not fly off but my air filter is always soaked in oil and when I pull the breather off the air cleaner I *see* thick cloud stream of vapors and when I put it to a rag, it is black. But I have no reference point as to what is excessive. And like clockwork if the temp falls around freezing overnight, it wont start without about 30 minutes of cranking despite a working new glow system. The smell from tail pipe is weird too as it is trying to start when it is cold. I guess it is unburned diesel but it does not smell like diesel. It is dry and musty. Maybe it is partly burned fuel.

thanks

Brian Carlton · #5 01-07-2006, 04:52 PM

Quote:

Originally Posted by biopete

And like clockwork if the temp falls around freezing overnight, it wont start without about 30 minutes of cranking despite a working new glow system.

Please state when the following maintenance tasks were last performed:

1) valve lash

2) injection timing

biopete · #6 01-07-2006, 06:04 PM

Quote:

Originally Posted by Brian Carlton

Please state when the following maintenance tasks were last performed:

1) valve lash

2) injection timing

Hi Brian. Thanks for the reply. I've talked about this in other posts and was not really trying to get off topic
of Excessive blow by . But if no one minds .. . (You could also PM me and I will follow up on my other post.when I get it solved. )

Valve lash done 3 weeks ago along with glow plugs, and reaming to 9/32 diameter with drill bit. Jury still out on that. diameter that hole should be

But I pulled an injector and glow plug protruded nicely into the open chamber so I am guessing that was sufficient.

I checked the injection start of delivery last week. I am pretty sure it is dead on but , not sure if I got it right. What I know is Fuel flow stops at the latest 20 BTDC . i could not ever land it exactly on 24 and gave up. When I set it to 24 and pumped and then waited fuel flow eventually stopped to a drip, drip. I am not sure if that was due to lack of pressure or correct timing.

Question -- should it drip only one drop per second even when you pump it? The Haynes implies that it should flow when you pump even at 24 BTDC and slow down to a drip per second. Again seeing as no fuel flowed when I did not pump i am confused whether lack of pressure or correct timing is causing the drip drip. Overall I am very confused about happening in the IP timing start of delivery procedure. It is very counter intuitive to measure "start of delivery" at the point the fuel flow stops Also, if there is another aspect to timing I have not heard of it.

Thanks a million in advance for help.

DieselAddict · #7 01-07-2006, 08:56 PM

The Search function is a wonderful feature...

Blowby:
OM616/617 Blowby survey

IP timing:
Checking/Adjusting IP Timing
White Smoke vs Inj Pump Timing

Hatterasguy · #8 01-07-2006, 09:18 PM

Quote:

Originally Posted by biopete

I *see* thick cloud stream of vapors and when I put it to a rag, it is black. But I have no reference point as to what is excessive. And like clockwork if the temp falls around freezing overnight, it wont start without about 30 minutes of cranking despite a working new glow system.
thanks

I'd call that a lot, sounds like my SD except mine starts in the 20's.

With a tight engine you should be able to pull off the oil cap and put your hand over it. You should feel slight suction.

For some reason lots of 616 and 617 owners seem to report lots of blow by.

Brian Carlton · #9 01-07-2006, 11:11 PM

Quote:

Originally Posted by biopete

Valve lash done 3 weeks ago along with glow plugs, and reaming to 9/32 diameter with drill bit. Jury still out on that. diameter that hole should be

But I pulled an injector and glow plug protruded nicely into the open chamber so I am guessing that was sufficient.

I checked the injection start of delivery last week. I am pretty sure it is dead on but , not sure if I got it right. What I know is Fuel flow stops at the latest 20 BTDC . i could not ever land it exactly on 24 and gave up. When I set it to 24 and pumped and then waited fuel flow eventually stopped to a drip, drip. I am not sure if that was due to lack of pressure or correct timing.

Question -- should it drip only one drop per second even when you pump it? The Haynes implies that it should flow when you pump even at 24 BTDC and slow down to a drip per second. Again seeing as no fuel flowed when I did not pump i am confused whether lack of pressure or correct timing is causing the drip drip. Overall I am very confused about happening in the IP timing start of delivery procedure. It is very counter intuitive to measure "start of delivery" at the point the fuel flow stops Also, if there is another aspect to timing I have not heard of it.

Thanks a million in advance for help.

Well, if the valve lash is proper, the glow system is functioning properly, the IP timing is correct, the only other possibility for difficult starting is very late cam timing. Have you checked the cam timing using the marks on the tower as a reference?

With regard to the drip method, I sympathize. I've never mastered it myself and it definitely leaves you with a queasy feeling when you get done. The bubble method is superior AFAIK. But, the best way to set timing is with the RIV tool which electronically finds the marks (15 ATDC). It's accurate to 1/2 degree. One of the members will rent it out now.

biopete · #10 01-07-2006, 11:55 PM

Quote:

Originally Posted by DieselAddict

The Search function is a wonderful feature...

Blowby:
OM616/617 Blowby survey

IP timing:
Checking/Adjusting IP Timing
White Smoke vs Inj Pump Timing

Can I call you DA

I never searched for blow by yet but have been meaning to. This thread popped up and I thought it needed the definition and place to find the definition in it and I knew somone would point it out so I posted the question.

Regarding IP timing -- I searched and read posts on the subject here for at least 2 hours but never found your above links. You answer my drip method questions exactly in your posts . You put it well when you said

Quote:

Originally Posted by DieselAddict

IMO the thing to look for is the last degree at which you can get solid fuel to come out by priming the hand pump. Beyond that the flow will quickly start getting restricted. That's your timing point.

And stevebfl answered my other exact question in a post I found of page 6 of the "drip method" search results :

Quote:

Originally Posted by stevebfl

The concept to drip timing goes like this: The pump plunger goes down, uncovering the fuel feed hole, the plunger/piston goes up and closes the feed hole. At that time the fuel starts being pushed through the line and out the injector. This point is called "beginning of delivery. In the early pumps where the pump element check valve was removed, gravity caused the fuel to flow through the pump into the pump piston chamber and out via the missing check valve through the drip tube. As long as the piston was down and there was fuel in the filter the fuel flowed. As the pump was turned the piston eventually rose and when the inlet hole started to be closed the stream of fuel through the drip tube slowed untill no flow was attained with the hole totally closed. The one drip per time interval was the measure of how closed you were. If you were "no flow" there wasn't an exact position as no flow would continue till the piston again came that far down.

Anyway, I will recheck it tomorrow (Its gonna be 60 and sunny

) and take photos and make a how to out of it using Haynes manual and you alls great explanations. We definitely need a summary of the 50 threads on the subject,

Brian Carlton · #11 01-07-2006, 11:59 PM

Quote:

Originally Posted by biopete

We definitely need a summary of the 50 threads on the subject,

Please get the most relevant threads and give them to WHunter via PM. Ask him to put them in the sticky that he has created for the DIY links.

Keep it to two or three of the best of them. We don't want 50 threads on one topic in the sticky. The threads that included the details of the drip timing are very valuable.

biopete · #12 01-08-2006, 12:08 AM

Quote:

Originally Posted by Brian Carlton

Well, if the valve lash is proper, the glow system is functioning properly, the IP timing is correct, the only other possibility for difficult starting is very late cam timing. Have you checked the cam timing using the marks on the tower as a reference?

Thanks Brian. I have not done that. I will do it tomorrow. Haynes manual also mentions "Leake fuel injector". Not exactly sure how that works but thought i would throw it out there. Ill search on it sometime

pawoSD · #13 01-08-2006, 12:30 AM

Mine blasts out quite a bit of blowby, has since I got it with 207k on it, now at 233k, it is the same amout, and it starts reliably down into the -5ishF temps....so I dunno, its also quite fast (lots of power) so I am not too worried. Based on the last 26k, I'd say its doing fine.

DieselAddict · #14 01-08-2006, 01:30 AM

Hey biopete, I'm glad I was able to help.

#15 01-08-2006, 09:10 AM

My 300SD has pretty, we'll call it "impressive", blowby yet starts and runs great.

I've adjusted the IP timing, done the valve adjustments, and change the oil regulary. My cap flops around and does a lovely job of coating my valve cover with oil *gr* but then again the car is approaching 300k miles and I am still pouding out every last available HP

How are you going about starting your car? (Mainly asking about accel. pedal useage)