Classic Mustangs List Archive

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Mail From: Rich Silva (email redacted)


Hope I didnt miss it if it started this way... and if it did I apologize...
But...

I'm about to ask a question that many of you are going to have a "Well,
duh..." response to, so let me set some context before asking what may
seem a rookie question....

First the car... '65 Coupe. 302, 10.25-1, Twisted Wedge heads (big valves),
Roller everything, Performer RPM intake, 600CFM Holley Double-pumper
(that's been worked), headers, 2.5" Exhaust. (pay attention here) Crane
Hi-6 ignition, through a Pertronix setup.

The car runs well. I've got some drivability issues and (I believe) some
throttle response issues. But its fast, sounds great, and is fun to drive...

In particular, when "engine braking", I get those neat crackling "back-fires"
(not major ones, mind you, just those neat sounding pops as you slow the
car down for a corner or stop light...)...

Lately, more than one person has told me they smell gasoline around the
car when its running (I havent noticed it when my head is under the hood,
and I make it a point to not sniff exhaust pipes on a running car...).

I've checked the plugs the simple way... and they look immaculate (light
tan electrode all the way down to the bottom, somewhat darker on the
barrel).

I dont really have access to somewhere I could make "passes" at speed,
turn it off, check the (G*d D**m) *HOT* plugs. Change things and try
again...

Has anyone got any good methods of determining if you're running too rich
or too lean?

With the Aluminum heads, I really am looking for more than a "make the jets
smaller, see how it runs..." answer...
--
Rich Silva (email redacted)
Voice - (310)414-3101 Fax - (310)615-4547

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This read-only message was archived from a public mail list.
Mail From: Bill Meisenheimer (email redacted)

Rich Silva wrote:

>
> In particular, when "engine braking", I get those neat crackling "back-fires"
> (not major ones, mind you, just those neat sounding pops as you slow the
> car down for a corner or stop light...)...
>
> I've checked the plugs the simple way... and they look immaculate (light
> tan electrode all the way down to the bottom, somewhat darker on the
> barrel).

> Has anyone got any good methods of determining if you're running too rich
> or too lean?
>

You're doing the right thing in checking the plugs, but it would be nice if you
could do it after some full-throttle runs also. With that much compression and
today's gasolines, be sure to watch for signs of detonation (cracked insulators,
blisters or aluminum balls on the plugs, etc.).

The light backfiring on deceleration you mention is generally caused by a lean
mixture, but since this is at closed-throttle, it isn't much of a worry. It will
probably go away if you richen the idle mixture a bit - this may also improve the
throttle response problem you mentioned.

Bill






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