Problem with valve adjustment on cyl #1 ('85 300d) - PeachParts Mercedes-Benz Forum

Zacharias · #1 09-26-2014, 07:23 PM

Planned to do several pre-winter things today on my 1985 300d: install rebuilt injectors, change glowplugs, adjust valves.

The last one is giving me a weird problem.

I am having a really hard time getting the adjustment wrenches onto both the cap nut and the locknut for the #1 exhaust valve, more so the locknut. I thought I was just losing my marbles until I tried them on the other valves, and they seem to fit fine.

Second, the valve was tight. Ouch. But try as I may I cannot get more than 0.28 mm adjustment out of it, which is better than it was but a long way off 0.35.

One thing I should mention is that I have one of the two-wrench sets with the red handles, that were sold back in the day on eBay. I have used them since 1998 on four cars and never had an issue, but is the lack of a lockwrench for the valve cap nut the issue here?

Thanks

Diesel911 · #2 09-26-2014, 08:23 PM

I am not sure if this will work but I think if do what is needed to kee the Engine From Starting and you Crank the Engine the Valve Rotators on the Valves will Rotate them so you can get a wrench on them.

The Stock 2 Wrench Hazet Set also can have a simlar issue as the Handle will hit the Fire Wall. You might also see if a regular Wrench would work although on the lower Nut the wrench needs a 1/4" Thick head.

People used to recomend several Methods of holding the top Spring Retainer so it would not rotate and that worked till I think it was 2 People over the space of 2 years cracked/broke their Valve Guides.
Not sure why in the last 2 of the 7 Years I have been on the Forum that is happening?

Hunter posted a thread 2-3 Weeks ago with some links. One of the links was on makeing the 3rd Wrench to hold the Spring Retainer.

Zacharias · #3 09-26-2014, 08:55 PM

What I mean is that the 14mm adjusting wrenches won't fit onto the locknut and the cap nut. Not easily anyway.

I did manage to get them on and turn the nuts but it's really difficult.

On the other valves they just slide on as they ought to.

It is like both nuts have mushroomed. Very weird.

leathermang · #4 09-27-2014, 12:43 PM

Quote:

Originally Posted by Zacharias

......It is like both nuts have mushroomed. Very weird.

I do not think you are crazy.... those cap nuts take a beating.... the FSM says put news ones on.... and you want to do that before they are deformed enough that it affects the threads on the VALVE... yikes... repair after that would involve taking off the head for a valve job...
And others should remember that there are more than one model of camshaft... some are chilled iron... etc...
and the other items in contact with them MUST MATCH.....

Zacharias · #5 09-28-2014, 11:53 AM

Part of the issue was that I was very tired and it was end of day when I started the valves, then wrote the first post.

It went better the next day, but it took me as long to get 0.35 out of that first valve, as it took to do all the rest combined. But I got there.

The cap nut isn't the bad one, it's the locknut and it isn't consistent. I found that my 14 mm regular wrenches fit okay except in one orientation where I had to move it a bit with a 15 to reorient it. So I used a combo of wrenches to get it done.

The spring is turning with the nuts on #1 so I guess I need that third wrench.

The rest of the valves were fine, several still in spec or near to it. Only #1 and #5 exhaust were seriously out.