driving with a bad lifter?
in [Technical]
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From: cuhulin on 4 Apr 2010 22:51 It is possible it could be a weak valve spring. cuhulin
From: George on 7 Apr 2010 00:05 On Sat, 03 Apr 2010 21:37:09 -0500, jim <"sjedgingN0Sp"@m(a)mwt,net> wrote: >> Further testing: I found a piece of (steel) flat stock, 0.1" thick, that >> just fit between the rocker and the valve stem. With the engine off, >> that made it tight. But, with the engine running, it's as noisy as >> before. >> >> So, among other things, it doesn't look like the lash cap would solve >> anything. At the same time, does this tell me anything about where the >> problem is? What I have is ... >> >> - Much noise. Listening with a stick, it seems to emanate from that >> lifter/push rod/rocker arm. >> - The rocker arm has ~.1" of lash, with the engine off. >> - The push rod is bringing oil up - possibly even more than the others. >> - Taking out the rocker arm lash doesn't affect the noise. >> >> After looking at some cars, the idea of replacing the lifter is getting >> more appealing. But, I'm wondering if the problem may be more than > >Seems to me it is likely it is not a collapsed lifter, but it is pretty >hard to diagnose through some one else's eyes. Here's a question for you >- If you had a broken valve spring would you be able to spot that? How >about a stuck valve that isn't closing all the way? If that engine has >roller lifter it could be the roller or the bearing that is busted. You >should really get a good diagnosis before you wade in over your head. I'm pretty sure I'd recognize a broken spring, though I'll look again. As for a stuck valve, ... I don't know that I've ever had one, but I think I'd see something other than the noise. Engine power is normal, no backfires (it's an exhaust), and we've driven it enough to get the engine warm, so I think it would have burned? Anyway, .. After some more running with my 'shim' under the rocker arm, the lifter tightened up. (!) (ie, the lash came out.) The noise was the same, though - no magic. It is a roller lifter. I can imagine that's involved; though, I can't picture how to account for all the play that was in the rocker, and then for that to go away, but still explain the noise. As in my other post tonight, I think it's time to just let it go. Thanks much to all who posted. George
From: George on 7 Apr 2010 00:05
On Sat, 03 Apr 2010 19:56:07 -0500, Vic Smith <thismailautodeleted(a)comcast.net> wrote: > Been through this a few times. My observations. > You have 3 choices. ... Thanks. >Not an easy decision. Good luck. Logic says, junk it - lots of rust. Would you pull the head without getting it machined? Probably not, I'd guess. That would be the clincher - I could maybe talk myself into gaskets & bolts, though the car isn't really worth even that. Nor the time. Just for the rust, we'd have to replace it before winter. G |