Re: Tom's bouncing compression - SOLN?

[tsm1@xxxxxxxxx]

> I may have to run home at lunch and look at a motor, but here is my guess
> for now.  The lifters for #7 are flat because of a plug missing in the
> valley.  That or the exhaust lifter for # 7 is stuck up causing that valve
> to not close.  Especially since you said " the answer is staring right at
> you in the first pic.", The #7 exhaust lifter is reflecting the flash back
> at us.

Drum-roll please.

Here's the brain-dead move of the month..

When rebuilding the 304C race motor over the winter, I was disassembling
each lifter, and along the way lost one of the spring-clips that holds the
"cup" into the lifter.

Since I had a full set of NEW lifters for the 392, I borrowed a spring
clip from one of the set, to put the racer together.  To remind me, I
turned the "cup" part of the plunger assembly upside down, so I'd KNOW not
to just throw this lifter in when I got to the 392.

Apparently, I remembered to put the clip in, but somehow completely blew
off flipping the "cup" back over.

This is why the "left" #7 lifter reflects the flash so well. IT'S FLAT ON
TOP.

Ed - I had the same theory as you for the first day or five about the
problem being valve/valve-train related, but just couldn't see how it
could continue to be valvetrain.. but it sure made sense, since it seemed
to work fine until I pulled the rocker shaft off and put it back on.

So I have two theories thus far.

1) Somehow I managed to get the pushrod n' such installed in such a manner
that the valve actually worked when I left home, but on the roadside in
Colorado I couldn't reproduce such luck.

2) It didn't matter what I did, that lifter just took a while (900 miles?)
to pump up, and when it did, it kept the exhaust valve open (since the
lifter is "taller" than it should be)

Either way, it seemed to not have a vacuum issue until after the pushrods
broke.  It never audibly BOUNCED before then, so I'm leaning towards "I
just didn't put it back in the right magic way.."

I remember trying to put that pushrod back in, and I couldn't "feel" the
lifter like all of the others.. just felt "off" and "vague".. I wanted to
look at the lifter, or pull it, and see why it felt so funny, but the
brake booster was in my way, and of course once we pulled the engine out,
we'd already decided to SWAP IT, not rebuild it before heading for home.

The pictures of the carbon deposits here and there, and the light
"scratches" - which I think are just thin carbon lines left by the top
ring - were mostly taken before Michelle started asking questions.. "Why
are the pistons at different heights?"  "See the other crank over there,
with the offset journals.. blah blah.. " "What are these?" "Those are
lifters."  "Why does this one look different?"  "Hmm.. uhh.. D'OH!.. Let's
take a look..."

So.. I think I'll clean everything back up, try and re-RightStuff the
valley and everything, and put the engine back together.

I still have one or two extra head gaskets (same brand), should have one
more tappet gasket.

First I'll CC the #7 chamber and then let it sit overnight and check for
any leak-down that might indicate a bent valve or poor valve seating, just
in case it hit - though I see no sign.

Motor won't go back in for a while though.  I have a shop to get ready for
this winter (as in, paint floor, wire, bring gas/electric to it, insulate,
sheetrock, etc) and a wedding in October, right before hunting season..
etc.  Good news is, my front end might be ready by then (only a year
late..) and the new shop should be big enough to put the Travelette inside
and work on it.

I have the new-to-me 5spd w/ PTO to install at the same time, so the front
clip'll come off and I'll swing it all in together.

-Tom