Hydraulic valve compensator adjustment - Mercedes-Benz Forum
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 185 (permalink) Old 03-10-2019, 09:01 AM Thread Starter
Lifetime Premium Member
 
Stutz's Avatar
 
Date registered: Oct 2009
Vehicle: 1999 500SL, 1988 SEC
Location: Rochester Hills, MI
Posts: 925
Mentioned: 17 Post(s)
Quoted: 223 Post(s)
Lifetime Premium Member
(Thread Starter)
Hydraulic valve compensator adjustment

I have a 560 with hydraulic valve compensators. I had a valve job done but they did not shave the heads. Upon redoing the heads on assembly I put in new lifters but kept the old compensators. All tested good using the hammer test method. Early on I tried to set the adjustments on the valves using the go no go guage but gave up since the measurements were all over the place. I drove the car for about 200 miles and thought I heard a valve train noise so took the drivers side valve cover off to inspect things. All seemed fine but I thought I would see what the valve readings were. I have extra pucks so that was not an issue. All valves showed the pin in the tester lower than it should be. I started at one valve and was able to get it in spec by putting in a thinner puck. However just for the heck of it I measured one valve and it showed low but I then compressed the spring, pulled the rocker, let it sit for a minute, then put the same rocker back in. It now showed ok. So how does one asjust these if the readings change? I am doing what the service manual says but wonder if the compensators being a little older can change after you release pressure then put pressure back on. I have been chasing my tail trying to do this correctly.

Any input from those who have done this appreciated.
Stutz is online now  
Sponsored Links
Advertisement
 
post #2 of 185 (permalink) Old 03-10-2019, 11:17 AM
Outstanding Contributor
 
John350's Avatar
 
Date registered: Nov 2014
Vehicle: 1990 350SDL, "Grandpa's Roadster" Project Car
Location: New Hampshire
Posts: 2,800
Mentioned: 9 Post(s)
Quoted: 789 Post(s)
I don't have the service info handy, but, in general, you have to deflate the lifters (make them bleed down) before you can measure anything. They have a range of clearances they can compensate for, and the adjustment is to ensure the "dry tappet clearance" is within that range. When you put spring pressure on the lifter it bleeds down. How fast that happens depends on the thickness of the oil and the wear in the lifter itself. New lifters with cold, thick oil won't bleed down very quickly. You'll get different readings if they are pumped up, partially bled or "dry".

John
"Real engines don't have spark plugs!"
John350 is online now  
post #3 of 185 (permalink) Old 03-10-2019, 11:37 AM
Outstanding Contributor
 
John350's Avatar
 
Date registered: Nov 2014
Vehicle: 1990 350SDL, "Grandpa's Roadster" Project Car
Location: New Hampshire
Posts: 2,800
Mentioned: 9 Post(s)
Quoted: 789 Post(s)
I just read over the documentation (05-213) and apparently they're assuming the lifter is pumped up, not dry. So, you have to crank the engine over and get oil pressure up there, then quickly move the engine until the rocker in question is on the base circle of the cam, not the lobe, then take the measurement. This should be under zero lash conditions. The compensator should be spring loaded to favor zero lash, so as long as you don't waste a lot of time, and don't push real hard on the tool, you should be able to get repeatable measurements.

John
"Real engines don't have spark plugs!"
John350 is online now  
Sponsored Links
Advertisement
 
post #4 of 185 (permalink) Old 03-10-2019, 01:16 PM
Moderator
Outstanding Contributor
 
MBL87560SEC's Avatar
 
Date registered: Jul 2004
Vehicle: 1991 500SEC sub 50K mi. 1987 560SEC Now 150K mi. 2018
Location: Boston, MA area
Posts: 3,763
Mentioned: 18 Post(s)
Quoted: 383 Post(s)
Lifetime Premium Member
Garage
Just in case someone needs the service info on this, here is the Valve Clearance PDF John is referring to.

M
Attached Files
File Type: pdf 05-213.pdf (468.3 KB, 40 views)
mramay and ianrandom like this.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

91 500SEC EURO Germany
87 560SEC USA 49 State Version
MBL87560SEC is offline  
post #5 of 185 (permalink) Old 03-10-2019, 01:54 PM
BenzWorld Veteran
 
Dikdaan's Avatar
 
Date registered: Jan 2014
Vehicle: 1977 450 SEL 6.9
Location: Vancouver, Canada
Posts: 704
Mentioned: 2 Post(s)
Quoted: 116 Post(s)
In my experience that "Hammer handle test" is BS, I have yet to see a lifter, even one that was shot yield to this test.
jsebastian likes this.
Dikdaan is online now  
post #6 of 185 (permalink) Old 03-10-2019, 02:03 PM Thread Starter
Lifetime Premium Member
 
Stutz's Avatar
 
Date registered: Oct 2009
Vehicle: 1999 500SL, 1988 SEC
Location: Rochester Hills, MI
Posts: 925
Mentioned: 17 Post(s)
Quoted: 223 Post(s)
Lifetime Premium Member
(Thread Starter)
John, I did have the lifters pumped up and could not get repeatable measurements. I wonder now if older lifters might have some variability in them? As such it makes getting the right pucks in for adjustment difficult. You also have to knowthat the difference is subtle but enough to throw the readings out of whack

Last edited by Stutz; 03-10-2019 at 02:12 PM.
Stutz is online now  
post #7 of 185 (permalink) Old 03-10-2019, 04:42 PM
Lifetime Premium Member
 
liviu165's Avatar
 
Date registered: Aug 2013
Vehicle: 1989 MB 420SEL, 1991 560SEC
Location: Atlanta, GA
Posts: 2,573
Mentioned: 19 Post(s)
Quoted: 611 Post(s)
Lifetime Premium Member
Two questions please:
1) Since the geometry was not altered on the cylinder head, things should not have changed if the parts were installed in the exact same location as before. So my question would be: When you installed the valve train components, did you install them in the exact same location as before?
2) You said "All valves showed the pin in the tester lower than it should be". My question would be: After the installation of the parts, did you turn the engine (the FRM suggests for 30 seconds) to pump the oil in the lifters before taking height measurements?

TIA
liviu165 is offline  
post #8 of 185 (permalink) Old 03-10-2019, 04:59 PM
Outstanding Contributor
 
John350's Avatar
 
Date registered: Nov 2014
Vehicle: 1990 350SDL, "Grandpa's Roadster" Project Car
Location: New Hampshire
Posts: 2,800
Mentioned: 9 Post(s)
Quoted: 789 Post(s)
If they ground the valves and seats, everything is different. (If they didn't, what was the point?)

The pin gauge measures the extension of the hydraulic compensator. It has to be within an acceptable range of its total movement to accommodate all running conditions.

If the readings are not repeatable, something is wrong. The extension of the compensator is determined by the profile of the cam lobe, the geometry of the rocker and the height of the tip of the valve stem. The only thing that can, or should, vary is the compensator itself, and if it does, it will introduce clearance between the cam and the rocker.

John
"Real engines don't have spark plugs!"

Last edited by John350; 03-10-2019 at 05:03 PM.
John350 is online now  
post #9 of 185 (permalink) Old 03-10-2019, 05:07 PM
Outstanding Contributor
 
John350's Avatar
 
Date registered: Nov 2014
Vehicle: 1990 350SDL, "Grandpa's Roadster" Project Car
Location: New Hampshire
Posts: 2,800
Mentioned: 9 Post(s)
Quoted: 789 Post(s)
Quote:
Originally Posted by liviu165 View Post
You said "All valves showed the pin in the tester lower than it should be".
That actually makes sense. Grinding the valves and seats moves the valve deeper into the head, so the stem sticks up higher which the compensator accommodates by not extending as far out.

John
"Real engines don't have spark plugs!"
John350 is online now  
post #10 of 185 (permalink) Old 03-10-2019, 06:10 PM
Outstanding Contributor
 
luckymike's Avatar
 
Date registered: Mar 2010
Vehicle: 1989 560SEC, 1989 560SEL, 1995 E420
Location: NorCal
Posts: 3,696
Mentioned: 5 Post(s)
Quoted: 523 Post(s)
I'm looking for a new answer on this, as well. My experience was the same as Stutz's. I could not get repeatable results. Even with cranking the engine to build up pressure as John350 states.
jsebastian likes this.
luckymike is offline  
Sponsored Links
Advertisement
 
Reply

  Mercedes-Benz Forum > Mercedes-Benz Sedan Forums > W126 S,SE,SEC,SEL,SD,SDL Class

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Mercedes-Benz Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 2 (0 members and 2 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Similar Threads
Topic Author Forum Replies Last Post
Understanding cold start DG91500SL R129 SL-Class 37 03-02-2019 01:59 PM
C250 Diesel shut-off valve leak repair wimc W202 C-Class 37 04-20-2017 01:18 PM
FLU-419 PTO, three point, drawbar and remotes bordercollie4u Unimog 8 10-28-2015 10:53 PM
Remote control of hydraulic circuits in 416 cab? aaronsb Unimog 24 11-02-2013 11:08 AM
Valve cover gasket replacement – 95 E320. 71Rcode W124 E,CE,D,TD Class 0 03-10-2004 05:50 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 

Title goes here

close
video goes here
description goes here. Read Full Story
For the best viewing experience please update your browser to Google Chrome