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Re: generic question on compression checks

To: "Tom Strange" <tstrange@new.rr.com>, fot@autox.team.net
Subject: Re: generic question on compression checks
From: "Brad Kahler" <brad.kahler@141.com>
Date: Thu, 17 Oct 2002 11:32:39 -0500
Hi Tom,

To the best of my knowledge its still using the stock type of lifter.  
What I don't know is whether or not he replaced them when he put in 
the new cam.  Thats a question I need to ask him.

I'll keep you posted as to the outcome....

Thanks for the feedback.

Brad

On 16 Oct 2002 at 18:31, Tom Strange wrote:

> 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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