Hi Brad,
I agree with you, I would be inclined to worry about the cam. I agree
with the leakdown check for sure. Then, you could put a dial indicator on
the push rods. (it seems this engine should have hydraulic lifters... which
will make checking it a little touchier... if it is solids, just check the
rocker arm clearance.)
This will probably tell you if you have a cam going away. This may not be
definite, if it is just starting to go, and you dont use dummy lifters to
get a real accurate reading, but it might just tell the story. This would
also give you a chance to check for things like broken valve springs etc....
It doesnt make sense to me for the compression to come up, then down, then
back up again, I'd like to hear some opinions on that.
Good luck, I'm interested in what the outcome will be on this one.
Tom
----- Original Message -----
From: "Brad Kahler" <brad.kahler@141.com>
To: "Bill Babcock" <BillB@bnj.com>; <fot@autox.team.net>
Sent: Wednesday, October 16, 2002 5:17 PM
Subject: RE: generic question on compression checks
> Hi Bill,
>
> The air pump has long been removed from this engine. It originally
> came with a catalytic converter but some PO removed that. I forgot
> to mention its a 79 jeep 360 engine.
>
> I didn't ask if he had done a leak down test or if he only did a
> compression check. I'll ask him about that when I talk to him again.
> Thanks.
>
> Brad
>
> On 16 Oct 2002 at 15:04, Bill Babcock wrote:
>
> > How old is this Jeep?
> >
> > First thing I would do is a leakdown test on all cylinders--compression
> > testing doesn't tell you what going on unless it's gross failure. If
they
> > are all holding well, then my assumption would be that the emission
> > control stuff was cattywumpus. On newer vehicles virtually every system
> > that could emit vapor or stuff feeds back into the engine for burning
and
> > catalyzing into warm mothers milk plus CO2. It doesn't take much for all
> > this stuff to stop working right, and when it does, you're screwed. In a
> > simpler time I'd say check the PCV valve, but new motors hardly even
have
> > them.
> >
> > I consider myself a decent mechanic, which means I don't B.S, myself
about
> > my limitations--I don't touch anything under the hood of any engine
newer
> > than 1970. I don't even change the oil. A rebuilder will be
clueless--they
> > are machinists and parts switchers. Here in Portland we're lucky enough
to
> > have one garage owned by a guy who has all the equipment and understands
> > all this stuff. I take everything that's off warranty except the Ferrari
> > to him.
> >
> > Find a guy like him.
> >
> > -----Original Message-----
> > From: Brad Kahler [mailto:brad.kahler@141.com]
> > Sent: Wednesday, October 16, 2002 2:04 PM
> > To: fot@autox.team.net
> > Subject: generic question on compression checks
> >
> >
> > Amici,
> >
> > This isn't really Triumph related (other than its a tow vehcile!) but
I'm
> > looking for guidance on an engine problem.
> >
> > We had an engine rebuild in our Jeep last spring and over the
> > course of the next year we had over heating problems, lack of power
> > and apparent blow-by.
> >
> > We took it back to the rebuilder multiple times to try and get the
> > problem(s) corrected. Never did have much luck. However, trying
> > to get past the state emissions test last month this almost new motor
> > failed miserably.
> >
> > Here are the apparent symptoms. OIl in the air cleaner coming from
> > the valve cover. Compression check shows approximately 140-145
> > across all 8 cylinders at first. However on the 3rd revolution of each
> > compression check (which is what the manual says to check for) the
> > pressure drops to 115-120 but comes back up to 140-145 on the 5th
> > revolution.
> >
> > This doesn't sound like a piston ring problem to me. It would seem
> > to be more of a bad cam. The cam shaft was replaced, the heads
> > were given valve jobs. Basically it was a complete engine rebuild.
> >
> > Any thoughts on what to look for? Should he just pull the heads and cam
> > on the assumption that the rings are probably ok? Or does this sound
like
> > a ring problem AND a valve/cam problem?
> >
> > Any help on this would be greatly appreciated!
> >
> > Thanks
> >
> > Brad
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