"jim beam1" wrote:
> wlw-19958 wrote:
> > Hi There,
> > New here. I would like to ask a question about what I found
> on my
> > 1994 Accord when I checked out an idling problem. I found
> out I had
> > Zero compression in No: 4 and 180 to 187 psi in all the
> others. I
> > pulled the head and found one valve that was severely burnt.
> All the
> > other valves look fine The valves in No: 4 have
> significantly more
> > deposites on them than the other three chambers do. Only
> one of the
> > valves (exhaust) in No: 4 burnt (and boy, did it ever burn).
> > other exhaust valve in No: 4 has deposits about equal to the
> > valve. The valves in No: 1 - 3 are all clean (well, stained
> > virtually no deposites at all). I checked the
> > clearance on the burt one and it is within specs. The valve
> stem is
> > within specs for a new valve (well above "service" limit).
> > So, my question is: "why did this valve burn?" Was it:
> > * Improper valve adjustment,
> > *
Intake gasket leak,
> definitely not.
> > * Problem with the fuel injector,
> definitely not.
> > *
Defective valve, or
> possibly, but rare.
> > * Something else I canít think of.
> if the valve set gets damaged in some way, [think gunk falling
> into the
> cylinder from a plug change, or a plug insulator nose
> fracturing &
> falling into the cylinder - these pieces can get trapped under
> a valve
> head, score the surface and initiate minor leakage.] the
> leakage will
> initiate "burn". it starts slow but accelerates from there.
> > To give you some background, This is a F22B2 SOHC (non-VTEC)
> > with about 100,000+ miles (I canít remember the exact
> mileage right
> > now). The timing belt was replaced roughly 10,000 miles
> earlier and
> > the valves were adjusted.
> > My first reaction is that the valve adjustment is to blame
> but I
> > checked the adjustments at least twice. Yes, the engine was
> > (room temperature). It had been up on jacks for a week
> waiting for
> > parts.
> > I wonder about the deposits on the exhaust valves in No: 4.
> Why would
> > this be the only cylinder to exibit them? Did they develop
> before or
> > after the valve burnt? If before, this would be a reason
> for the
> > valve burning out. But is still begs the question as to Why
> just this
> > one cylinder is developing deposits?
> > What do you folks think?
> > -Blue Chips-
> > Webb
> deposits are because without proper compression, you're
> insufficient combustion to heat the components enough to clean
> when you replace the valve & run the car normally, the
> deposits won't
> be aware that this vehicle may fail smog next time around - if
> too much
> unburnt fuel's been reaching the catalyst, it may have burnt
> out. but
> address the valve issue first & see how it turns out.
Thanks for the information. I suspected that it was the adjustment.
I did the adjustment durring winter and the car was in outside. Could
the colder temperatures affected the adjustment? Should I have added
more clearance to compensate for the colder conditions I was working
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