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  • Javelin

    Feb. 13, 2011 12:21 p.m. Javelin SuperDork

    Did a compression test again and found 0 in cylinder 2. So I popped off the valve cover and found this:

    That would be the rear intake valve and both exhaust valves on cylinder #2. Looks like collapsed lifters. I can push the lifters down more easily and the springs pop them right back up, but not all the way to the cam.

    So maybe just 16 new lifters and it's fixed? No metal bits in the head or the oil (I have a magnetic plug from FM) and compression was 185 on all 4 before the ticking became permanent knocking. I imagine the odd knock I was getting now and then was one or more of these collapsing for a rotation or two before pumping back up.

  • mad_machine

    Feb. 13, 2011 12:28 p.m. mad_machine SuperDork

    hopefully that is all it is.

    Might be able to get away with just new lifters for the dead ones

  • Javelin

    Feb. 13, 2011 12:30 p.m. Javelin SuperDork

    If 3 are dead, it's only a matter of time before the other 13 fail. I'm debating whether or not to fix it though.

  • Feb. 13, 2011 12:44 p.m. triumph5 Dork

    There's that saying, "Well, while you're at it...." is most appropriate at this juncture, given what you've told us in the past.

  • Wonkothesane

    Feb. 13, 2011 4:35 p.m. Wonkothesane Reader

    You could try cleaning them and inspecting them before replacing them all: http://www.miata.net/garage/hla/cleaning.html

  • mike

    Feb. 13, 2011 5:27 p.m. mike Reader

    I did the cleaning according to the link above with "great success." Before the work, the lifters would clatter a LOT, off and on, throughout the drive. Now I get a few seconds of noise from one lifter on cold mornings, and that's it. These are lifters with about 150K miles.

  • Javelin

    Feb. 13, 2011 6:28 p.m. Javelin SuperDork

    Mine already have 163K, but what the hey, it's only time and some oil right?

  • iceracer

    May 17, 2012 5:44 p.m. iceracer UltraDork

    In the old days we would just give it the "Bardahl" treatment.

  • Zomby Woof

    May 17, 2012 5:49 p.m. Zomby Woof UltraDork

    If the lifters won't return and touch the cam, why is there no compression?

    Sounds like stuck or bent valves to me.

  • Cone_Junky

    May 17, 2012 5:57 p.m. Cone_Junky Dork

    In reply to Zomby Woof:

    Because the intake valves won't open. No incoming air, so nothing to compress.

  • ransom

    May 17, 2012 6:04 p.m. ransom Dork

    In reply to Cone_Junky:

    One intake is maybe opening (or at least the lifter's making contact), and I'd expect to see some compression from just the air sitting in there at atmospheric, no? It's still getting squished at whatever-the-CR-is-on-a-Miata...

  • Javelin

    May 17, 2012 6:10 p.m. Javelin UltimaDork

    Can't make compression with 3 valves stuck open

    The car is long sold (and fixed) BTW.

  • Zomby Woof

    May 17, 2012 6:20 p.m. Zomby Woof UltraDork

    Didn't even notice the date. So what was the problem?

  • Javelin

    May 17, 2012 6:53 p.m. Javelin UltimaDork

    In reply to Zomby Woof:

    See the pics? 3 collapsed lifters, stuck the valves open. Apparently the new owner pulled them all out and rebuilt them, engine was okay.

    Keith says new ones are cheaper now, not that hard to do, but you do have to pull the timing belt and cams.

  • Zomby Woof

    May 17, 2012 8:15 p.m. Zomby Woof UltraDork

    I've never seen a collapsed lifter hold a valve open.

  • Keith

    May 17, 2012 11:11 p.m. Keith MegaDork

    I managed it in my Locost engine. Too much time with an 8000 rpm redline and stock valve springs. And I have a Miata in my garage right now that I suspect has the exact same problem.

  • iceracer

    May 18, 2012 9:25 a.m. iceracer UltraDork

    That doesn't bring up stuck lifters, Just maybe bent valves.

  • May 18, 2012 9:44 a.m. Nashco UltraDork

    Zomby Woof wrote:

    I've never seen a collapsed lifter hold a valve open.

    Ditto...I don't understand how the lifter being collapsed would prevent the valve from closing. I could see a collapsed lifter not pushing the valve open (or opening very little) but then you'll see your compression tester fluctuate between vacuum/low pressure and higher pressure as you crank the engine (if you release the check valve).

    Bryce

  • DrBoost

    May 18, 2012 12:00 p.m. DrBoost UberDork

    Maybe you could measure the lash that you have. Then you can pull the lifters out, and lay a weld bead down that's just a little thicker than the lash you measured. then you can file the weld smooth and to dimension.
    See how smart I are?

  • Keith

    May 18, 2012 1:06 p.m. Keith MegaDork

    In my case, I jammed the lifter in the head when it collapsed. Or more accurately, BS Levy did Not a bent valve, although I did replace it.

 
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