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  #1  
Old 11-05-2010, 04:41 PM
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Location: Mckinney,Tx
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Valve adjustment limits

Adjusting my valves on w123 with turbo. I have all three hazet wrenches. I have one stuck valve. Yes, i know how to use the wrenches correctly. My question is, "Is it possible to run out of all adjustment?" I am wondering is it time for a new valve, or can i grind the top of the valve down. I currently have 312000 miles.

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1984 MB 300D 266,000
1993 Nissan PU 271,000
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2004 VW TDI 75,000
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  #2  
Old 11-05-2010, 05:47 PM
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I do not see anything physically wrong with the idea of Grinding a little off of the top of the Valve Stem if this allows the upper Adjustment nut to go down further.

However, is the top of the Valve stem is what is hitting the Upper Nut or is there not enough threads when your turn both adjusting nuts all the way down?
If you are running out of threads; you might remove some metal from the bottom of the Upper Nut (the threaded end) to allow it to go down further.

None of the above is a replacement for finding out what is wrong and Fixing it.
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Old 11-05-2010, 06:01 PM
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Grinding top of valve stem

I have had to replace one of these valve nuts before with another one. I am wondering if it was stripped internally as well. Not a fun job, but doable. I was wondering if it was the valve seat giving it up to age. This one adjusted fine last time i was in there.

Always something with the ole benzo. Time for a break, need some Jack.
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airedale2 Welcome to Texas
1984 MB 300D 266,000
1993 Nissan PU 271,000
2002 Tahoe 122,000
2004 VW TDI 75,000
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Old 11-05-2010, 08:26 PM
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The car hasnt done enough miles for the valve seat to have given up!! What gap do you have? Inlet or exhaust?
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1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
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  #5  
Old 11-05-2010, 08:52 PM
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Valve adjustment problems

Okay, I figured it out. After a glass of Jack and watching my son spin around on the floor I think I have figured where I went wrong.

The big nut on the top of the valve spring(that caused me to purchase the full set of hazet wrenches in the first place) is threaded on the top of the valve as well. It must have turned too many times in its own seat and used up the remainder of the valve lash. This is why I ran out of adjustment in the valve. I will have to pick up another valve thrust nut and replace the existing one and then adjust the third nut on the bottom accordingly.

On another thought, the last time one of my thrust nuts stripped, I had to think of how wonderful an engineering job those germans did. I noticed that the thrust nut metal is not as hard as the valve(exhaust) metal. This idiot proofs damage to the valve itself and leaves the part replaceable.

I will try to finish up the valves/repair on Monday as I will have to pull new parts. I guess is why Mercedes emphasizes that third wrench so much. I know you can get by without it, but this is a good example of why it is nice to have the right tool for the right job.

Thanks for everyones input, Hope this helps someone out in the future.
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airedale2 Welcome to Texas
1984 MB 300D 266,000
1993 Nissan PU 271,000
2002 Tahoe 122,000
2004 VW TDI 75,000
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  #6  
Old 11-05-2010, 09:11 PM
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Quote:
Originally Posted by airedale2 View Post
The big nut on the top of the valve spring(that caused me to purchase the full set of hazet wrenches in the first place) is threaded on the top of the valve as well.
No. The "big nut" (valve spring retainer) is indexed to the valve and cannot rotate relative to the valve. It is retained by the lock nut.
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  #7  
Old 11-06-2010, 08:07 AM
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Quote:
Originally Posted by tangofox007 View Post
No. The "big nut" (valve spring retainer) is indexed to the valve and cannot rotate relative to the valve. It is retained by the lock nut.
That is interesting... I need to have a closer look at this when I adjust the valves next week.

I have seen the top of the spring turn before when adjusting the valves. But, I always stopped, positioned the nut and spring back to their original position and moved on.

Now, I also wonder if I am over tightening all of those nuts?
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  #8  
Old 11-09-2010, 04:41 PM
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VALVE ADJUSTMENT LIMITS

Well, finished adjusting my valves yesterday. Had to replace another valve thrust nut. This gave me just enough clearance on the valve adjustment. No more after that.

Car runs so much better now. I also pulled an extra vtn for a spare from the donor. I'll probably have to do some filing on the valve next adjustment.

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1984 MB 300D 266,000
1993 Nissan PU 271,000
2002 Tahoe 122,000
2004 VW TDI 75,000
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