Dave WM

valve guide seals

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    in an attempt to reduce oil  consumption (1q 1000 apx) I decided to replace the intake guide seals. I decided to only to the intakes since its not an easy task and I figure the exhaust side would not suck oil anyway. Based on the condition they have been I would think its prob not going to help anyway since the old ones seem pliable, but maybe a bit larger diameter where the valve stem seals.

    I was going to do a video but that is just too hard to capture so I thought I would share my process.

    removed the valve cover, and all the plugs. used a 19mm on the camshaft bolt to turn the lobes with the intake lobe straight up, this is past TDC on the piston stroke.

    used some rubber hose that just fits into the plug hole, then used my seal puller pliers to choke up on it near the plug hole so I can push it in it will not go any more. The pliers help grip in close to the hole so you don't have the hose bending while trying to stuff it in.

    rotate the camshaft back so the lobes are "bunny ears" this will push the piston up to TDC and really jam the hose up against the valve. I forgot to mention I used the natural bend in the hose and aim for the intake valve.

    loosen the rockers jam nut and run the pivot all the way down. remove the rocker arm retainer spring, the pry off the rocker from the pivot. I used the 17 mm wrench handy to lift up on the back of the rocker near the pivot. I suppose you could also just depress the valve spring  a bit to. Just make sure you keep up with the lash pad. It will prob  stay over the valve but stil...

    with the rocker out of the way use the OHC valve spring compressor, the kind that hooks around the cam shaft (not the lobes) and has a pivot point that allows for downward pressure on the valve spring. You may want to give the top of each valve spring a light smack with a large drift to loosen up the retainers.

    while depressing the valve springs use a magnet on a stick (small) and retrieve the two retainers. with them out the spring release to its full height. While doing this its a good idea to watch the valve stem it may move downward some, but if the hose was set right it will be very little. the less movement the better since you do not have to depress the spring as much.

    remove the spring assy (two springs an inner and outer and a cap, keep up with the lash pad (get that out before attempting the retainers with the magnet). watch out for a spacer that sits on the bottom of the spring stack, it prob will stay on the top of the head, but you want to make sure as you remove the springs.

    now the easy part use the valve stem seal puller pliers to remove the old seal, just grab it mid section and gently pull up. Careful here as the pliers will want to jump up and you are right next to the cam lobe, just don't want to scratch anything.

    I soaked the new Nissan seals in some motor oil to install, then use the pliers above to push it into  place. you can see when it bottoms out.

    replace the valve springs, setup the spring compressor, replace the retainers (yea just like that, presto). the retainers can be a bit of a pita. I used some hemostats and would set one in place from the driver side, ease up on the compressor while rotating the retainer around so the next one will be easier to go in. A single retainer once set will hold it together while you get the next retainer setup on the hemostats. I tried for a 10/4 or 2/8 position as this was where they were when I started. You may want to look make note of this for yourself.

    anyway after some fiddling with the second retainer it will just drop in an your are done. replace the rocker and reset the lash.

    Have fun!!

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

    Edited by Dave WM
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    Dave, I did one valve seal (#1 intake) in situ. I didn't take pics of every stage, but I did take a few. So here's a couple pics to go with your text.

    I used rope (not rubber tubing). Stuff the cylinder full and then rotate the crank to push it upward into the valves:
    P1150544.JPG

    Once you have the springs off, pull the old seal up and off:
    P1150546.JPG

    And put the new one on. Be sure to use the little straw so you don't mess up the new seal on the sharp edge corners of the retainer groove:
    P1150547.JPG

    And when I put it back together, I used a short length of rope to hold the spring compressor tool in place (with the springs compressed). That way I could use both hands to fiddle with the retainer wedgies instead of trying to manage the tool in one hand while giving a wedgie with the other. Process looked like this:
    P1150548.JPG

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    well this sux, took it around the block before the curfew starts, loud ticking from what sounds like #5...

    pull the valve cover. all the lash pads are in place and the hot check of the lash is .010 in .012 ex

    Darn it. I wonder if its possible to damage a valve. I never exerted any more force that to break the bond on the retainers, Did not turn the crank with any real force to compress the rubber tube.

    Its pretty loud...

    So tomorrow I guess I get to do a leak down test and see if I can hear any issues. darn darn darn...

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    one thing I did NOT keep up with is the rotation of the lash pads. So I could have installed one 180 out from the orig. I did one valve at a time so the rocker/springs/lashes are all the same.

    CO yes I did use the valve stem condom to protect the seal from the sharp edge of the valve stem.

    Edited by Dave WM

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    reg compression test shows nothing out of the ordinary, 155-165 low/high. will do a leak down next to see if I can hear anything odd out of the intake.

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    well the leak down test showed nothing out of the ordinary, 90psi in 82-86 out, could hear NOTHING from then intake manifold, it was all the rings.

    So since the only thing I really changed was the guides and presumably I did not damage the valves, I suppose the most likely issue is something with the guides themselves? is it possible that if the guide pops off its perch it could make a tapping sound? I discounted that idea since they are rubber.

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    tried it again, def a metallic clanking coming thru on the drive side of the head could pick it out with the stethoscope. I will pull the valve cover off and look over that #6 valve again.

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    Is it possible a foreign object got into the cylinder?

    Acess to a bore o scope?

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    no way got anything in, I have a bore scope, but I am very sure about this. the mouse trap springs in place.

    1 experiment, I removed #6 spring and double checked my work (guide in, valve moves easy, spacer on bottom of spring stack. got an idea, I replaced the springs and keepers, but did NOT reinstall the rocker. disable the injector, start car and of course in missing but still clacking, same noise.

    So I am very sure it cant be the valves on #6, I did not even touch the exhaust. Since the rocker valves for #5 intake is right next to #6, perhaps its is that one. I am sure it comes from the very rear of the engine. So after the oil drains back some I will replace the rocker on #6 and just remove the rocker on #5 intake, not going to bother going further unless that quiets the noise.

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    oy, still nothing. I removed the rocker arm on the #5 intake, still making the noise. going to give it a rest and double check all the lashes just in case I goofed up and fiddled with an exhaust and forgot about it. Really starting to be bugged by this. I think the next try will be to run it with the cover off, plastic sheet the engine bay and see if I can locate the offending part with a clear (oily) view.

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    I would check the combustion chamber for debris

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    here is the plan. Put it all back together, double check the lash on all valves, bore scope the cylinders, If it still making the noise (will get a video of it with sound) I am just going to pull then engine and put in my spare. The spare runs great, has the MN47 head (higher compression). I don't really want to get into pulling the head with the engine in the car.

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    Woof. Are you positive sure it's a metallic clanking? And are you positive sure it wasn't there before? Maybe you're just uber sensitive to noises right now? I'm (like you) am having a hard time coming up with anything that could cause that kind of noise as a result of a valve seal change.

    So you did all six intakes? Just the intakes only?

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    8 minutes ago, Captain Obvious said:

    Woof. Are you positive sure it's a metallic clanking? And are you positive sure it wasn't there before? Maybe you're just uber sensitive to noises right now? I'm (like you) am having a hard time coming up with anything that could cause that kind of noise as a result of a valve seal change.

    So you did all six intakes? Just the intakes only?

    Its obvious, I can hear it inside the car with the window up. Plus I can use the stethoscope, touch each spark plug body, its very noticeable on #5 (IIRC or could have been #6). not there at all on the others.

    yes did all 6 intakes did not touch the exhaust. Its a real puzzle. The video will help will post that up today after I get it all back together. the only thing I can come up with is:

    I am just really really not getting the lash set right or I bent a valve with my rubber tube technique. I don't see that as likely but the only possibility left (well short of me dropping something into the cylinder). It sounds like a valve set way loose. I triple checked the lash pads are in place (besides checking both hot and cold lash) already but cant hurt to try again.

    If this fails I the only thing I need to do to the spare motor is replace the timing chain tight side guide, new timing cover gasket, new rear main seal, new pan gasket, new oil pump gasket. I will leave all the manifold stuff on as I can see no reason to replace it other than my existing setup has the egr, the spare does not, but since its dumb there should be no wiring issue other than an unused water temp switch on the t stat.-

     

     

     

     

     

     

     

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    You could have dropped a valve seat too. It's pretty rare, but possible. It would make the valve lash wonky depending on how the valve seated against it and it would be pretty noisy. Might not be able to tell that with the camera though.

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    Have you tried just grabbing rocker arms and reefing them around to see if you can find looseness?  Put down the stethoscope and get rough.

    You might try removing the mouse trap springs and rechecking lash.  They add extra force that the feeler gauge has to overcome.  Might not be getting the right measurements.

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    2 hours ago, Patcon said:

    You could have dropped a valve seat too. It's pretty rare, but possible. It would make the valve lash wonky depending on how the valve seated against it and it would be pretty noisy. Might not be able to tell that with the camera though.

    do you think I could feel anything with the valve spring off, and me manipulating the valve? I did try that to see if I could feel any oddness as it seated. The other thing is the leak down test showed virtually no leakage (listen for it thru the intake manifold brake booster port with a hose). All the  cylinders sounded the same.

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    22 minutes ago, Zed Head said:

    Have you tried just grabbing rocker arms and reefing them around to see if you can find looseness?  Put down the stethoscope and get rough.

    You might try removing the mouse trap springs and rechecking lash.  They add extra force that the feeler gauge has to overcome.  Might not be getting the right measurements.

    I will give it a shot.

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    one last course of action besides the above, I plan to remove the valve cover, drape the bay with an old blanket, hole for the top of the engine, and run it with the cover off (vacuum plugged) figure I could feel the noise better this way. will make a mess, hence the old blanket to suck up the thrown off oil.

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    Smoking gun?1

    ok #6 EXHAUST completely loose, jam nut up, multiple turns and I am still not there. I just had to come in and shout this out!!

    Keep your fingers crossed, seems like this has to be it.

    Now how did this happen, being old (see covid) brings along a condition known as brain fart. I MUST have started there, or just got confused/distracted and loosened that one up before moving on the intake.

    anyway taking a break to let the possible joy last for a while just in case I am wrong.

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    I suspect in your senior state, you loosened up #6 exhaust lock by accident and then it worked itself out from there.

    Sounds like a plausible smoking gun to me! That would be great!  Tighten that sucker back up to the correct lash and take it around the block while you're still allowed!!!   :victorious:

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    this may sound silly but I am slow walking the adjustment, guess I want to live in the idea that this is it, enjoy the moment, make it last for a while just in case I am wrong...

    Tomorrow Tomorrow

     

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    12 hours ago, Dave WM said:

    this may sound silly but I am slow walking the adjustment, guess I want to live in the idea that this is it, enjoy the moment

    LOL. "I gots ta know."

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    2 hours ago, Captain Obvious said:

    LOL. "I gots ta know."

    click..... smile

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