Re: [Fwd: Passed emissions]

[jlandry@domain.elided (John A. Landry)]

As the putrid festering facial boil erupted, rhughes@domain.elided yelled:

>I've read (maybe on this digest, maybe on the Holley board) that
>power valves don't "blow" nearly as often as people think, but I still
>wonder if that's what had happened.

If I'm not mistaken, the power valve on the model 2210C can not "blow out"
per se.  It has no rubber diaphragm (as on other Holley models).  It's
possible it could leak... because it is a valve after all.  If it leaked,
this would effectively enrichen your mixture off idle.

Have you bothered to check other things on your engine... vacuum leaks, the
EGR system, PCV system, etc.?  Small problems can add up cumulatively and
be difficult to track down.  Your carb changes might be covering up
something else.

>When I get my AutoMeter vacuum gauge installed, I'll be able to watch for
>the power valve engagement, which should be interesting.

Sorry to disappoint you, but I don't think you're going to see what you
hope to.  All you'll see is the current manifold vacuum.  If you see a
vacuum change, you won't be able to tell if it's caused by road conditions,
throttle position or carburetor issues.  You need an air/fuel mixture gauge
(such as the one Cyberdyne manufactures) to monitor the status of the
exhaust.  I have both.  I'm able to tell *exactly* when the power mode on
my Edelbrock carb begins to open by observing the air / fuel mixture
rapidly enrichen only when the manifold vacuum drops to a certain level.  I
simply watch the mixture gauge and compare it against the present vacuum
reading.  The vacuum gauge moves around a lot depending on so many
factors... mainly engine load and throttle position.

>BTW, when I talked to a local speed shop about my problem, they said that
>.50 is *way* to small a jet for a 500cfm carb.  I'm not sure though, is the
>2210C 500cfm, or closer to 350?  Anyway, this guy seemed pretty confident
>that something is wrong with the carb if I have to jet that small.  He may
>be right, as this is an old, tired carb.

Nope... I think they don't know what they're talking about!  That jet is
not far from stock.  I'll try and remember to look up the stock jetting in
the IH shop manual tonight and e-mail you what I find.  The model 2210C is
very close to a 350 cfm rating *not* 500 cfm.

The carb probably could stand to be completely disassembled, soaked
overnight in carb cleaner and carefully reassembled.  You'd be surprised at
the accumulated varnish and crud this removes.

>Holley makes jets down to about .40, but they are kind of hard to find.
>Lots of parts stores could order them for me, but no one had anything
>smaller than .50 in stock.  This lends credence to what the speed shop guy
>said, I think.

I don't see what that has to do with anything.  I can't tell you how many
shops I've been in where the guys standing around were so full of BS, it
made me embarrassed to listen to them.  I'm not trying to come off as some
know-it-all myself, as much of what I know came from books and trial and
error.  But when the IH shop manual tells you the stock jet is supposed to
be a 502 (for example only) and some gear head tells you to install a 550
just because... that's total crap!  I work with a self professed hot rodder
who spends his weekend changing his carb metering rods and jets with no
idea of why he's doing it or plan to verify what's he's done.  But he's
always so full of advice on telling everyone what jets and rods to run in
an Edelbrock carb.  He's never read a spark plug, much less any sort of
exhaust monitoring gauge.  His car exhaust leaves black spots on the
asphalt and he crumbles about his plugs "loading up," yet he's telling me
how he's going to go richer on his carb.  I tried to politely explain to
him about proper air / fuel mixtures and such, but non of it would soak in.
I just shook my head and try to avoid him anymore.  What's sad is all the
other guys around here he's leading astray.  Sadly, he's the same guy who
sits down at the local speed shop handing out advice to willing listeners.
What's my point?  Just because you heard something at the local speed shop
doesn't make it good information.  Sorry to preach.

You'll get *much* better information for your IH vehicle here on this list
than just about anyplace else.

Regards,

John
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