<VV> bad lifter?

[Ramon Rodriguez III]

TLDR:  Why would tightening one particular intake valve rocker too far
cause RPM to increase instead of decrease?  Read on for details.



Update:  After sending my last message I decided to go ahead and remove the
lifter from the engine to inspect it.  I wound up taking out both of the
lifters for the #4 cylinder (mostly so I could compare them).

Both of those lifters took considerable effort to compress in the vice.  I
worked them back and forth in the vice until it became easy, then tested
them and was able to compress the pistons with my finger afterward.  I'm
not sure how much additional resistance there should be when there is oil
in the lifter but based on one of the tech guide articles that suggested
testing lifters by pushing on the rockers I think that they were giving too
much resistance. Note that the lifters are only a few years old and look
like new with a good wear pattern on the tappet end.

I freed them both up and put everything back together then did a valve
adjustment on those two cylinders.

Tightening the #4 cylinder intake valve beyond where it should be still
increases RPM significantly instead of momentarily pushing the RPM down
like it normally would.

It is worth mentioning that this problem is on the cylinder bank that took
some abuse from a defective carb dripping lots of gasoline into the
manifold during a few minutes of test driving, then later hydro-locked the
starter motor from that same carb leak (that is what lead to me finding the
problem).

I did a compression test after that and this bank is definitely weaker than
the right.  Either it sustained some damage from that leaking carb or it
suffered from excessive running temps on the drivers side bank during hot
weather highway driving (when my temp gauge reads highest by far).  My
engine is clean, my heads are de-flashed, and I never threw a belt so there
is no reason it should have overheated.

Compression test results:

Cylinder #            one crank      several cranks       crank until
highest reading

1                            135                  165
      170
3                            125                  160
      170
5                            125                  155
      180

2                            115                  150
      165
4                            100                  130
      150
6                            105                  140
      155



Thanks for any advice,

Ray R.




On Thu, Aug 22, 2013 at 4:04 PM, Ramon Rodriguez III <corvairgrymm at gmail.com
> wrote:

> In trying to get my hot rodded 140 running like it should I noticed that
> the left bank sounded like there was a rocker too loose so I did a hot
> adjustment today with the engine running and it did not solve the problem
> but I did find something interesting.
>
> The problem is on the intake valve on the #4 cylinder.  If I continue to
> tighten the rocker nut after getting rid of the valve lash the RPM
> increases instead of decreases.
>
> This seems to me to indicate a bad lifter, but I wanted your opinions.
>
> If it is a bad lifter (or you otherwise know what the problem is) please
> give suggestions on how to fix it.  I know there was some debate as to what
> lifters to use.  Also can I replace just the bad one?
>
> I am thinking of just tightening it to where it runs well until I get parts
> and fix it, is that ok?
>
> Thanks!
>
> Ray Rodriguez III
> Certifiable Vair Nut
> Lake Ariel, PA
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