Valve Adjust Question - PeachParts Mercedes-Benz Forum

Abner Mality · #1 04-07-2006, 07:30 PM

Tomorrow morning, I intend to adjust the valves on my '80 300SD. This will be my first such endeavor, and I have a couple of questions for the experts.

I intend to remove the entire accelerator linkage, after marking all the connections and links. Any handy-dandy tips would be helpful. I also plan on removing the injector lines, so they'll be out of the way, and this is the only thing that makes me a little nervous. Are there "O" rings at the pump and injector ends of the lines that I will need to replace? If so, what size "O" rings should I ask for at the parts counter at NAPA? How tight should I tighten the bolts on the valve cover after I've finished; snug, hand-tight, or tight-tight?

TIA

thorsen · #2 04-07-2006, 07:42 PM

Don't remove the entire linkage assembly, just undo the ones that attach to the valve cover. I would leave the injector lines in place too - you can easily adjust the valves without removing them.

Do you have the bent wrenches?

Brian Carlton · #3 04-07-2006, 07:48 PM

I like to remove the injector lines. Takes 10 minutes, maximum, and they are out of the way.

They don't use any o-rings. Just a tapered seat. Make sure you start the nuts by hand. If they won't make a full turn by hand, then force the tubes until they bend and the nut is properly lined up. The worst thing is to force it with a wrench.

For the valve cover, the proper torque of 11 ft.-lb. is rather critical to properly seal the gasket. If you are too loose, the gasket leaks. If you are too tight, you bend the valve cover and the gasket leaks.

Abner Mality · #4 04-07-2006, 07:59 PM

Quote:

Originally Posted by thorsen

Do you have the bent wrenches?

I do have the bent wrenches. Since this is my first attempt at this service, I intend to remove the injector lines so that I'll have a clearer path to the head. After I've done this a few times, I should know which shortcuts to take.

Thanks to you and Brian for the quick responses.

Brian Carlton · #5 04-07-2006, 08:13 PM

You do know how to "pop" the ball joints on the throttle linkage, right??

sokoloff · #6 04-07-2006, 08:16 PM

I've never had to remove the injector lines on my 240D to do a valve adjustment. Proper fluid to lube the ball sockets of the linkage is ATF.

Len

Diesel Giant · #7 04-07-2006, 09:18 PM

It is an easy job to do. Heres how.

http://dieselgiant.com/valveadjustment.htm

Abner Mality · #8 04-08-2006, 12:28 PM

Quote:

Originally Posted by Diesel Giant

It is an easy job to do. Heres how.

http://dieselgiant.com/valveadjustment.htm

My wife just recently purchased your deluxe diesel purge kit and the wrenches and vavle cover gasket, as a gift for me. I suspect she thinks I'm spending too much time in the house. I printed out your pictorials for the purge and the valve adjustment. I did the purge last weekend, and it made an unbelievable difference. I am purchasing a 420SEL from a member, and was planning on selling the SD. Now, I'm not so sure; I think I'll keep her around for tinkering purposes.

It has been chilly and raining, this morning, so I am still in the "prep" stage of the valve adjustment. I am literally under a shade tree, so can't do much until the rain stops. So far, I have cleaned the engine compartment, between showers.

As soon as I get 'er done, I'll post the results, the 0-60 times, and my overall impressions. Thanks, again, to all that have provided advice. This forum is the best.

Diesel Giant · #9 04-08-2006, 05:51 PM

Too much time in the house?

It is nice and warm here now, so I can be found under a hood of an oil burner.

Abner Mality · #10 04-08-2006, 07:38 PM

WOW! I did it. The sun finally popped out, around 2:00 p.m. It was still a might chilly, but I got things started. The first thing I did, after getting the valve cover off, was to check the clearances on all the valves. That gave me plenty of practice turning the engine with the nut on the power steering pump.

Every one of the valves was too tight; I don't know how the poor girl was even able to start, and I had been having a lot of trouble most of the winter with slow and no starting.

I had earlier marked my feeler guage with parts paint; "E" for exhaust, "I" for intake (smart, huh?). I did the adjustments in the order that the lobes came up to the correct position, then marked a small dot of paint near the valve that was done. Didn't miss any, but as I mentioned, they were all very tight.

Since I had the injector lines off, I went ahead and installed five new glow plugs. Having the lines off made that task much easier. I had purchased the plugs back in the winter, thinking they would help with my starting problem, but I checked the old ones with a multi-meter, and they all checked "good". The old ones were badly carboned, and I suspect they weren't able to heat up very well; we'll see in the morning.

Yes, in the morning. The backs of my legs were on fire by the time I got the plugs in, and I decided to wait until morning to put things back together. I am anxious to try out the "new" ride, and will post my results as soon as I have them. Not a bad feeling, either. This shade-tree mechanicing ain't so bad thanks to this forum.

Diesel Giant · #11 04-08-2006, 10:38 PM

Shade treeing can be very fun as long as you dont have to pull and engine or tranny.

Abner Mality · #12 04-09-2006, 06:50 AM

Quote:

Originally Posted by Diesel Giant

Shade treeing can be very fun as long as you dont have to pull and engine or tranny.

Yes, and I have the stiff lower back to prove it. 36° outside, and I'm trying to loosen up the old joints. All that's left to do is put the injector lines back on, clean up and install the valve cover, and hope my linkage diagram is suitable for amateur mechanics.

My biggest problem was that three of the valves wanted to turn as I was making the adjustments. It took some trial and error with various tools, but finally found that an 18" pry bar had just the proper angle on one end to jam them up. Had me wishing for that third wrench. The pictorial was a real help, too.

Al Magaloff · #13 04-09-2006, 07:39 AM

Abner, one tip I can pass on for next time, and for any of our taller members. Jack the car up! Treats the back a whole lot nicer.

Abner Mality · #14 04-10-2006, 02:16 PM

Was in the process of tightening the last injection line, yesterday morning, in preparation for re-installing the valve cover. Heard a loud "Thud" coming from the kitchen. Ran in, and found my wife in the middle of a bad seizure. She is now hospitalaized, and I am home for a shower and a nap. One of our sons and a daughter are with their mom, now, while I try to rest.

Will report on the valve adjust as soon as I have the time.

Abner Mality · #15 04-12-2006, 01:34 PM

Firstly, my wife is home from the hospital, and doing much better. Scary situation.

Secondly, as I promised, the report on the post-valve adjustment on my SD. I actually adjusted the valves and, while at it, installed new glow plugs. Had been experiencing difficulty starting all winter long, and lots of smoke on start-up.

The previous weekend, I had performed the diesel purge. That, alone, had made a big difference in the smoothness of the idle, and the sound of the engine. After I got everything sewn back up, the car did not start up right away. I was about to panic when it occured to me that the injector lines were empty of fuel. I cranked her for a few more seconds, and BINGO!

Before the work, I had to let the glow plug relay cycle twice (37 seconds on my particular SD), then count off exactly 28 seconds before the car would start. Yesterday morning, I decided to hit the starter as soon as the GP light went off (7 seconds, normally). The outside temp was 46°, the GP light went off right on schedule, and I hit the starter. Honestly, I don't think the engine made one full rev before she started up.

It was amazing. As soon as the initial glee subsided, I looked in the rear-view mirror -- NO SMOKE! As embarrassing as it is to admit to myself and this group that I had let that old gal go so long without a remedy, I am equally proud that I was able to pull off the task on my on. In addition, the money I saved in not having to drive 65 miles to West Memphis for German Auto Tech to do the work, more than paid for the diesel purge kit, the bent wrenches, valve cover gasket, and the glow plugs. Am I proud of myself, or what?

Finally, thanks to everyone who participated in this thread and the many others that I searched in order to build my confidence level. I sincerly doubt I could own this car without this forum.

Next project: both front window regulators are shot to heck, so they will be replaced with a pair of good used ones from a salvage yard.