Doug,
I sometimes also get backfire through the rear carb but only when cold
starting (79B converted to HIF's and foam filters). This would pop off the
damper. As Paul has suggested, I thought it was due to worn threads on the
plastic damper cover so I ordered a new one. Same thing occurs. You can
definitely tell when the damper cover is off due to the stumbling
acceleration. To remedy the damper from popping off, I used a hose clamp
wrapped around the neck of the air chamber cover. I then cut off a 1 1/2
inch piece of zip tie and looped it over the damper cover, stuck the ends
into the hose clamp and tightened the hose clamp down. This kept the damper
from popping clear loose, but it still loosened up a little. I eventually
modified it a little further by putting a small rubber grommet between the
damper top and the zip tie "strap" to give it a little more cinching power.
This has kept the damper cover in place for some time now. This was
important because I live on 4 miles of graveled, dusty roads.
Jerry-rigging at it's best (sorry, Gerry!).
Monte
79B, Carmine
67B, BRG
74 1/2 Rust, parts car
----- Original Message -----
From: "Paul Hunt" <paul.hunt1@blueyonder.co.uk>
To: "Douglas Gaither" <dbgaither@sbcglobal.net>; "mg list"
<mgs@Autox.Team.Net>
Sent: Friday, December 10, 2004 3:14 AM
Subject: Re: Backfire problem
> Backfiring in the *exhaust* can caused by a lean mixture and is common on
> cars with an air pump if the gulp valve has failed. It can also be caused
> by ignition problems failing to give a regular and consistent spark. The
> tach will be flicking if these are in the LT side, but not the HT.
> Backfiring in the inlet is altogether less common in my experience, but
> could be caused by valve or valve timing problems. Unlikely to be
directly
> associated with using a hotter stat unless something untoward happened
when
> you were changing it. A hotter stat and higher running temp will result
in
> higher coolant pressures, which could explain why the radiator is weeping
> now, but it must have been very marginal to begin with. A loose carb
damper
> shouldn't cause backfiring, but it will cause a stumble on acceleration.
If
> it is popping up and not simply coming unscrewed this is usually caused by
> worn threads. Replacing the damper may help if its plastic threads are
the
> culprit and not those on the alloy cover.
>
> PaulH.
>
> ----- Original Message -----
> From: "Douglas Gaither" <dbgaither@sbcglobal.net>
> To: "mg list" <mgs@Autox.Team.Net>
> Sent: Friday, December 10, 2004 5:06 AM
> Subject: Backfire problem
>
>
>
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