Replacing valve stem seals: Anyone ever do it?

Discussion in 'Dakar champion (950/990)' started by wiseblood, Jan 30, 2015.

  1. wiseblood

    wiseblood Quid Quo Pro Supporter

    Joined:
    Dec 29, 2008
    Oddometer:
    25,426
    Location:
    New York City
    Seems to work well enough for getting the keepers off! Getting them back on is another matter.

    FYI, valve stem diameter is 6 mm.
    #61
  2. wiseblood

    wiseblood Quid Quo Pro Supporter

    Joined:
    Dec 29, 2008
    Oddometer:
    25,426
    Location:
    New York City

    Can you describe the lever set up a bit more? This is definitely my problem area at the moment!

    If I can fab up a tool, I can finish this job in an hour.
    #62
  3. TheMuffinMan

    TheMuffinMan Forest Ranger Magnet

    Joined:
    Mar 31, 2010
    Oddometer:
    9,163
    Location:
    Grand Junction, CO
    That seems like a bit of a pain in the butt though interesting way of doing it. Personally I'd rather just pop off the heads and make quick work of it using a spring compressor tool.
    #63
  4. wiseblood

    wiseblood Quid Quo Pro Supporter

    Joined:
    Dec 29, 2008
    Oddometer:
    25,426
    Location:
    New York City
    It may come to that. If like to not have to install all new head gaskets and base gaskets.
    #64
  5. rider911

    rider911 Shortcut Navigator

    Joined:
    Sep 18, 2009
    Oddometer:
    1,280
    Location:
    Australia
    This is what I fabbed up when I did it in the bike. I used the frame as a lever point.
    I used a pen type magnet to remove and replace the collets.
    Should be way easy out of the bike except your going to need to fab a pivot point.


    [​IMG]

    [​IMG]
    #65
    DistortedAxis likes this.
  6. unaweep

    unaweep Uses lotsa band-aids

    Joined:
    Jan 2, 2006
    Oddometer:
    40,300
    Location:
    Western Colorado
    Rider911- I like it. :thumb Thanks for the pics. That would appear to make the reinstall a bit easier, too. No?:ear
    #66
  7. wiseblood

    wiseblood Quid Quo Pro Supporter

    Joined:
    Dec 29, 2008
    Oddometer:
    25,426
    Location:
    New York City
    :nod

    So, this weekend I was trying to design a tool which would make this installation easier. Bottom line is that I don't have enough leverage to compress the springs sufficiently.

    I picked up one of these simple valve spring compressors from the local auto parts place:

    [​IMG]

    I knew it wouldn't fit, but I thought I might be able to scavenge it for parts to make a tool. My idea was to use the cam bridge bolts in the head to hold it in place (couple M8's and M10's, some flat stock).

    Last things first: After looking at the head, I don't think it would work -- particularly for the valves opposite the cam sprockets, because they only have bolt holes (M8s) on ONE SIDE. This would create some serious torque, and I don't want to risk cracking my head. :fpalm

    Picture of head so you can see what I'm talking about:

    [​IMG]

    Damn pity, because that would be a sweet solution! It would make replacing seals IN-FRAME a snap! Maybe someone with more engineering and fab skill than me can figure it out. :freaky

    So, now I'm regrouping, and working on maybe a lever system like Rider911:

    [​IMG]

    I know he's just using a couple bits of stock, but I was thinking of using the tool tip from the tool I got:

    [​IMG]

    It fits without any filing needed, and it has a holt for a bolt in the end.

    So, one more FYI: I did a couple measurements of how far I need to compress the valve springs to get the keepers in. Short version is, "All The Way." The springs need to be just about bound to clear the threads on the valve stem into which the keepers lock. IIRC, about 24 mm from fully extended. Does anyone know what the spring rate of the two valve springs is supposed to be? I'm just curious how many pounds of force are required to compress the springs.

    Oh, and one other interesting tidbit: Cam lobes are only 8 mm longer on the point than in the closed position. That means you actually need to push the valve springs further to install the keepers than the cams normally move them.


    Here's another video of how the tool I'm using is SUPPOSED to work:

    <iframe width="560" height="315" src="https://www.youtube.com/embed/VIwmf0nhljU" frameborder="0" allowfullscreen></iframe>

    I haven't given up on this, yet. But, it looks like I need to get a lot braver about pushing down.
    #67
  8. Rharr

    Rharr Been here awhile

    Joined:
    Apr 5, 2014
    Oddometer:
    888
    Location:
    Tucson Az
    just fab up some thing out of wood that straddles the motor. Take a piece of plywood lay it on the table set motor on ply, screw down home made compressor to ply, slide motor underneath.

    Or you could find a cheap deep socket the is about the same size as the retainer, cut the side off the socket off the make a window, put a long extension on it, find a big friend and have him push down on the retainer while you fish in the cut out window to add or remove the keepers.

    it might help to move the motor to the floor if you try to push the retainers down with a friend, might want to also strap the motor to a peice of ply so it doesn't move around.
    #68
  9. wiseblood

    wiseblood Quid Quo Pro Supporter

    Joined:
    Dec 29, 2008
    Oddometer:
    25,426
    Location:
    New York City
    Definitely a good idea! I don't have much in the way of metal fab tools, so wood is an easy option.


    I'm about the most Sasquash person I know. (6' 11", 300 lbs :lol3)

    I wasn't quite to the point of holding ALL my weight on the valve, but I was definitely concerned about breaking something.


    Done! :beer
    #69
  10. wiseblood

    wiseblood Quid Quo Pro Supporter

    Joined:
    Dec 29, 2008
    Oddometer:
    25,426
    Location:
    New York City
    Friday, with the help of another inmate (:beer), I was able to finish up the rear cylinder. :clap

    I tried a couple different tools, but ultimately, this worked best:

    [​IMG]

    [​IMG]

    Using bench for leverage:

    [​IMG]

    I tried using the "Keeper Remover / Installer" tool, but it appears to be best at REMOVING, and not so good at INSTALLING! Best I ever got was close, but no cigar:

    [​IMG]

    And, then there was the one time I almost lost a keeper down the cam tower:

    [​IMG]

    :eek1

    Fortunately, with the gentle use of a zip tie and a long pliers (magnet was too big) I was able to get it back:

    [​IMG]

    :knary

    (BTW, there are openings at the bottom of the valve holes for oil to flow down via the cam tower to the sump. When you block this area with towels, make sure to stuff enough down there! :deal)

    Once we had the tool sorted out, we were able to do the remaining three valves in about an hour: Removing the valve springs, pulling and replacing the seals, and re-installing.

    The hardest part was for the second person to get the damn keepers in place. I put a dab of grease on the end of the valve stems which helped hold the keepers as we slowly released the pressure on the springs. All the time, we maintained about 50-70 psi in the cylinder.

    Reassembly was pretty uneventful, with ONE EXCEPTION: The shim buckets didn't fit right. There is a small amount of lateral movement in the springs. When I went to put the buckets back in, they were "sticking" making it necessary to really push them down. The solution is to tap them with a mallet and appropriate soft tools once you have them installed to "center" the springs as needed. (No air pressure in the cylinder for this: You want the valves to move a bit.)

    All buttoned up!:

    [​IMG]

    [​IMG]

    I used lots of engine oil on the cam journals for installation, to assure nothing "starts dry."

    While each valve spring was out, I tested the valve guides for wear. I did this by trying to laterally wiggle the valves. None of them had any play I could detect. FYI, I found it easier to do this test with the oil seals installed, because they provided enough drag to prevent the valves from moving "up-down" when I was testing for "left-right." (No air pressure when testing this.)

    :freaky
    #70
    DistortedAxis likes this.
  11. docgonzo

    docgonzo Old Gadfly

    Joined:
    Mar 1, 2002
    Oddometer:
    20,104
    Location:
    within 20 miles of the Center of the Universe
    I'm confused. Are you saying that the valve guides, in fact, didn't need to be replaced? I was surprised that an engine with just 30,000 miles on it would need this work. I'm sure it was fun to take everything apart, but was it a worthwhile "voyage"?
    #71
  12. wiseblood

    wiseblood Quid Quo Pro Supporter

    Joined:
    Dec 29, 2008
    Oddometer:
    25,426
    Location:
    New York City

    Yes, that's what I'm saying. The Valve GUIDES did not need to be replaced. The Valve SEALS did. :deal
    #72
  13. docgonzo

    docgonzo Old Gadfly

    Joined:
    Mar 1, 2002
    Oddometer:
    20,104
    Location:
    within 20 miles of the Center of the Universe
    Well, I guess you will find out when you have it all back together and start riding it again. Hopefully, it won't foul the plugs anymore or lose oil!

    [​IMG]
    #73
  14. wiseblood

    wiseblood Quid Quo Pro Supporter

    Joined:
    Dec 29, 2008
    Oddometer:
    25,426
    Location:
    New York City

    Yep, I would hope!

    FYI, valve seals are part #4, here:

    [​IMG]

    Valve guides are parts #11 & #12, here:

    [​IMG]

    Seals can be replaced (as I have done) without removing the head. If your guides are toast, you have to pull the head to replace them. (I think... :hmmmmm).
    #74
    DistortedAxis likes this.
  15. unaweep

    unaweep Uses lotsa band-aids

    Joined:
    Jan 2, 2006
    Oddometer:
    40,300
    Location:
    Western Colorado
    I'm eager to hear if everything came together and that the bike runs! Fingers crossed for ya. :thumb
    #75
  16. wiseblood

    wiseblood Quid Quo Pro Supporter

    Joined:
    Dec 29, 2008
    Oddometer:
    25,426
    Location:
    New York City

    Bumpity-bump!


    Ok, so it's been a heck of a year, in every way possible. You know how they say "Life is Short?" :nono Life is LOOOOOOONG! Especially if your motorcycle looks like this:

    [​IMG]

    :fpalm

    Anyway, that was January. Jan 30, apparently, as that is when I started this thread. :fpalm :fpalm :fpalm

    So, to catch everybody up, here's what has happened:

    1. It was time for the 20k mile service.
    2. My bike always consumed oil, so I figured now was a good time to fix the problem. Which I assumed (wrongly) was the valve stem seals. Right! Waaay too easy! :lol3
    3. After dropping the motor and starting to take off parts, I did a leak down test and didn't like what I found.
    4. At the urging (and quite a bit of pointing and laughing) of a couple friends, I decided it would be foolish to NOT fix this problem correctly. One of the exact quotes was: "You've gotten this far and you're NOT going to do a valve job? That's like swimming halfway across the Atlantic ocean, deciding it's too far, and turning around." Thanks, friend! :finger :lol3
    5. After some discussion, I found a machine shop on the west coast which could do the job right, for a price I could actually afford.
    6. Sent out the heads. For 'em back some weeks later.
    7. Finally getting around to putting it all back together! :clap

    So, for starters, BEFORE:

    [​IMG]


    AFTER!:

    [​IMG]

    Did it suddenly get hot in here? :drif





    Continued....
    #76
  17. borderxx

    borderxx ifalldown

    Joined:
    Dec 16, 2005
    Oddometer:
    179
    Location:
    Northern Arizona
    So, we can expect another update in, like, February?

    :lol3:lol3
    #77
  18. docgonzo

    docgonzo Old Gadfly

    Joined:
    Mar 1, 2002
    Oddometer:
    20,104
    Location:
    within 20 miles of the Center of the Universe
    Old joke:
    What is the only difference between a heart surgeon and a motorcycle mechanic?
    The heart surgeon needs to do the valve job while the engine is still running! :jack

    Can you imagine if my son took 9 months to do a valve job? And still not have the patient back together again?
    #78
  19. unaweep

    unaweep Uses lotsa band-aids

    Joined:
    Jan 2, 2006
    Oddometer:
    40,300
    Location:
    Western Colorado
    :lurk
    #79
  20. wiseblood

    wiseblood Quid Quo Pro Supporter

    Joined:
    Dec 29, 2008
    Oddometer:
    25,426
    Location:
    New York City

    :finger :lol3

    So, anyway... continuing!

    I got the cleaned-up valves and heads back from APE a bunch of weeks ago. My motor has been sitting on my workbench for months now, waiting on various parts. For the curious, here's what an open LC8 look like:

    [​IMG]

    [​IMG]

    And some seriously dirty exhaust valves:

    [​IMG]

    So, new heads arrived about 6 weeks ago, and looked very pretty:

    [​IMG]

    [​IMG]

    [​IMG]

    Big thing (which I could not do myself) was installation of brand new valve guides. This is most likely how the oil was getting into the combustion chamber. :deal

    So, the thing which finally pushed me to get the valve job done was the leak down stats. The rear cylinder was leading 9-10% through the rings, and the front was leaking 4-5% through the intake valves. So, I might as well replace the rings while I'm in there:

    [​IMG]

    [​IMG]

    FYI:
    1. The top of the oil scraper and middle ring are clearly marked, but the top compression ring is not. However, it has a lip which should face UP.
    2. Clocking the rings: The service manual doesn't specify, but the best advice I found was to have the top ring gap oriented away from the exhaust side, and the other two rotated 1/3rd around, each. Like this:
    [​IMG]

    Continued.....
    #80