rassan frassan %$%#^@ SD... - PeachParts Mercedes-Benz Forum

vstech · #1 03-26-2008, 01:09 PM

stupid thing... wouldn't start yesterday (first time my SD ever gave me problems...) worked on it all night, pulled valve cover (went to dealer and got new gasket...

) checked all the valves... all the intakes were LOOSE??? and all the Exhausts were TIGHT! I mean really tight. like over a full turn to get the feeler in there! I finished the adjustment, but it still did not start. I figure I still gotta bleed the injector lines... anyway, the starter started making this WHIRR noise while cranking. kinda like a motor with bad bearings spinning free... but it was cranking smooth... starter is gonna go soon I am sure.
also the glow plug light is not consistent. the light does not come on. I checked the relay strip fuse, it's perfect. I checked the glow plugs all 5 are pulling the same .6 ohms... should I pull all the GP's and visually test them? I hate it when a car does not cooperate...

#2 03-26-2008, 01:16 PM

Check the voltage at the actual GPs while they are glowing, that will tell you if it's a relay problem. Expect to see about 11V.

leathermang · #3 03-26-2008, 01:21 PM

Tight exhaust valves is really dangerous for your engine.... how long do you go between setting them ?
Don't worry too much about the glow plug light as long as the actual glow plugs are working... that light is just a suggestion light....
Have you considered checking to see if your glow plugs are being sealed off by carbon built up over the years ? Are you going to check your precombustion chambers to see if the pintle is still there intact ? Have you considered pulling your precombustion chambers to see if those radially drilled holes are clean and open ?
Over the years you can have a little deterioration in a dozen parts of the engine... then one morning it does not start... and no one item fixes it completely....
A good starter and plenty of good juice going to it really helps....
On the glowplugs.... turn them on and count to 40 then try starting it.... the FSM says they continue to heat up for about a minute...and there is a lot of difference in their temperature between usual time and waiting longer to engage the starter... of course the FSM has a chart....

hangit · #4 03-26-2008, 01:22 PM

Quote:

Originally Posted by vstech

should I pull all the GP's and visually test them?

It probably wouldn't hurt to visually inspect them. How old are they? It helps to have a 12mm ratchet wrench to remove them. Wish I had one!!! Ream the port while you have them out.

John

vstech · #5 03-26-2008, 02:20 PM

I replaced them all before last winter. I should have adjusted the valves at the same time... I hope I don't have 5 burned exhaust valves... I did pull all the injectors when I adjusted the valves... makes it easier to turn over the motor, and better for me to access the valve adjust nuts... anyway, all the pintle balls are intact. and what I could see of the glow plugs looked good... should have engaged the relay while I had it all open... arrgh. another set of heat shields... up in smoke. oh well. onward and upward. I'll pull a starter from the 85 and swap it out, voltage verify the GP's and go from there. if the plugs are all getting voltage, and they all pass the visual heat up I will get a compression test on it... hopefully, it's just air in the injector lines...

come on... wish me luck!

OH, I just remembered! BE CAREFULL WHEN CLEANING OFF THE HEAD to put the valve cover gasket back on... that ALDA line is BRITTLE!!! good thing I have 4 parts cars!

hangit · #6 03-26-2008, 02:29 PM

Gooooooood Luck John!

John

winmutt · #7 03-26-2008, 03:40 PM

Dumb question, did you ever see fuel with the lines cracked?

vstech · #8 05-26-2008, 12:26 AM

... ok, I started working on this again today... I pulled the entire head off the 85 to swap it over to the 82... I may swap over the block as well, MAN that thing is in AWESOME shape inside... the chain guide has hardly any lines in it... perfect... except for that spun rod/main problem... we shall see once I get the tranny separated off it and put the block on the engine stand tomorrow sometime... (I sure do use ellipsis a lot...) anyway, I may pull the block from the 82 and swap over whatever rod is spun, and flush out the 85's block and swap over the crank and get new bearings and have a MUCH better condition motor in my 82SD, how much trouble is it swapping over the oil filter base from the .951 to the .952?

oh, and winmutt, yeah a dumb question... then again, it's only the unasked question that is truly dumb.

Hatterasguy · #9 05-26-2008, 01:42 AM

I don't understand, what was the problem?

These engines are basic they need compression and fuel to start. So if they just don't start one morning I'd blame fuel. Even a low compression 617 should start this time of year without glow plugs. Shoot a little candy into the intake and light it off if that is the case.

Heck mine had enough blow by that it looked like a train and it still fired off cold down to 50 or so without the GP's.

vstech · #10 05-26-2008, 09:13 PM

it was not an all of a sudden thing, over the course of the winter it got progressively harder and harder to start. and one day it just would not.
I never new what a good 617 motor ran like until I got my 85 parts car. that thing started instantaneously, without any glow, and there was NO BLOW BY, NONE!!! I mean it ran so smooth I couldn't believe it. then I got the 83 SD, and it was a perfect motor as well, and the 84D I just bought with over 315K on it, still had better blowby than my 82SD driver did... I feel I waited WAAAAY too long to adjust the valves, and think the exhaust valves ate the seats... I got perfect glow, and perfect fuel, just no cranky cranky... the aged beast must be dead. before I pull the head off the driver, I will do a compression test, but I am really leaning towards a rebuild. like I said, I have some really pristine parts to make a perfect rebuild candidate. and I really want to get into a 617 engine. I will mostlikely make the 83SD into a daily, and make the 84D into a fun cruiser. and leave the 82 to be totally restored. I love the original MB I aquired, and I don't think I will ever let it die or get sold. so I want to do the best for her.

so, back to my question, what is the difficulty of swapping over the oil filter assembly on a .951 to a .952 block?

tyl604 · #11 05-26-2008, 10:12 PM

John- I have had a daily driver 81 300SD since 1984. It has always started in approximately two seconds of cranking after the glow plug light goes off. For some two or three years it has vibrated a LOT at stoplights but I never worried about it. This winter it began to take one to two minutes of constant cranking to get it started - very unusual. I thought this was due to the extreme cold - nearly 45 degrees F in Atlanta - and switched to 5-30w oil; this has helped in the past. This time it did not help.

Finally I took it to my mechanic and had the valves adjusted; first time since 1984 (have 252K miles on the engine). He said they were very tight.

Long story short. It now starts again after one to two seconds again and the vibration has almost gone away. With luck you may have the same experience.

Starter - this is pretty elementary but it sounds like your solenoid may be going. Years ago these could be replaced on american cars and I assume same may be true with the MB.

vstech · #12 05-27-2008, 09:51 AM

Quote:

Originally Posted by tyl604

John-
Starter - this is pretty elementary but it sounds like your solenoid may be going. Years ago these could be replaced on american cars and I assume same may be true with the MB.

nope, it was a slightly bad battery... I took it down and had it tested, found a bad cell, wouldn't put out full CCA. the motor now spins freely, but still will not crank up.
I will report back as soon as I have the compression test.

rivermasternc · #13 05-28-2008, 09:22 PM

John:

I saw a similar deterioration of starting in my '83 SD over a couple of years. My practice on debugging the glow plugs was to look for ones with open or very high resistance. When I go to the point I could not get the car started, I replaced all the plugs. Appeared to be 3 plugs that were bad, but still giving me relatively low resistance readings (analog multimeter).

Glow plug fuse okay?

-Scott