Valve Job - O2 Sensor Question

Greetings: I've got a '92 Accord (175,000 mi). Have been trying to
really give it a thorough upgrading without a total overhaul, and just
wondered if either or both of the following two things could possibly
increase engine performance and longevity: (1) valve adjustment
and, (2) a new O2 sensor. Neither of these issues has ever been
addressed over the life of the car. I have anecdotally heard that
a valve adjustment and/or new oxygen sensor could enhance
performance, but would like to hear it from someone out there in
the real world before shelling out real money. Thanks. - Paul

 

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Do you mean 'performance', or fuel economy. Your wording isn't clear.
Valve adjustment should follow the manual's recommendation, (unless
there is a known error, like the CRV manual) and the PCV often gets
overlooked.

Why not list the stuff you _have_ done?

'Curly'

 

Hi Curly: Yeah, performance synonymous with fuel economy is
on track. And, you know, "smoothness" in driving for lack of a
better term. OK, here's a rundown on what's been done recently,
all values in miles:

1) New plugs, Bosch Platinum +4 (don't laugh, 'cause they
work great) at 175,000. These really made a difference.
2) New rotors at 175,000, after-market but they work fine.
3) Machined drums at 170,000
4) New brake pads/shoes/master cylinder at 170,000
5) New radiator / timing belt / water pump at 150,000
6 New radiator fan timer, engine coolant temp. sensor,
gauge sender, fan sensor, and thermostat at 150,000.
7) New EGR valve/EGR solenoid/PCV valve at 135,000.
8) New tires (Michelin HydroEdge) so I don't go hydo-
planing all over Canada like before with my 4mm
Harmonys.

So what's left? I'd love a transmission overhaul but can't afford it
and don't know how to manage it myself. Maybe I'll take one of
those six-week night classes at the local community college and
learn how to do this. Seriously, I'd love to. Just don't have the
time. So that's back to my original questions. Namely, what kind
of benefit (or lack thereof) might a valve adjustment and/or new
oxygen sensor have on this particular car? Thanks again. - Paul

 

paul, there's not a massive amount of point in replacing the sensor
unless it's giving you trouble. but hey, it looks like you /want/ to do
it, so go ahead.

regarding valve clearance, i'm not sure about the accord, but the civics
specify 0.17-0.22mm inlet, 0.22-0.27mm exhaust as a range, with 0.20mm
& 0.25mm being typical. i have mine adjusted to the minimum of the
permissible range because it theoretically gives slightly extended valve
opening. the result is /definitely/ rougher idle, but arguably better
performance. i can [just] out-perform all other d15b2 hondas i've
encountered my vintage, but i can't guarantee that's solely attributable
to valve adjustment.

 

Hi Jim: I really appreciate your input. It sounds like auto
tuning is a lot like just about everything else in life...it all
depends on what you want. Interesting about the idle on
your civic. Rougher but better performance on the one hand,
versus (I presume) smoother but less performance on the
other. Trade-offs, trade-offs, and more trade-offs. : )
Thanks again. - Paul