Hi David,
Thanks for your reply. Your idea of using a supplementary pump sure
makes sense to me. My TD MkII has two pumps, so one is likely to be in
service at any time, but in our MGB I keep a small USA auxiliary pump
just in case the faithful SU that's mounted out of harm's way, just ahead
of the RR tire, protected by the dirt, mud and crud of the road, lives.
I have set it up with short rubber fuel hoses and clamps so that if the
trusty SU were to take a vacation, the auxiliary pump could be hooked
into the fuel line just ahead of the carburettors, and the wires lead
around the engine to the fuse block on the opposite side. A real plus to
the SU pumps is that one may either push fuel through them or pull fuel
through them, without having to remove the SU.
Now that you have mentioned it, I have noticed altered performance in
the SUpumps during hot weather. They seem to 1) run very fast for a time,
or 2) hesitate. The job gets done, but the pumps do act strangely. One
supposes that the test for this would be to tape the cover to the pump
body so to make it watertight, then pour cold water on the pump when it's
acting strange.
Bob
On Sun, 13 Jul 1997 16:44:31 -0500 dmeadow@juno.com writes:
>
>On Sun, 13 Jul 1997 07:01:22 EDT mgbob@juno.com (ROBERT G. HOWARD)
>writes:
>>Hi Ron,
>> The fuel pump on the early TFs was on the firewall, as it was on
>>TDs. Apparently there was a vapor lock problem with it, as the pump
>>was moved to a location near the fuel tank so it would pressurize
>more
>>of this fuel line/system.
>snip
>
>There was an article about this issue in one of the British
>enthusiasts mags recently. Although the article wasn't that good, it
>did seem to imply that most if not all "vapor lock" problems were due
>to failure of the SU fuel pump. The theory was that heat affected the
>fuel pump, and when it cooled it would work again, which mimics the
>effects of vapor lock. The writer felt that he had confirmed this by
>determining that his car stopped because the fuel pump was not
>working. Again, the article was not very scientific, but may help to
>confirm why the pump was moved from the firewall to near the tank in
>later MG's. Besides better pressurization, it may also have helped to
>get it out of the heat of the engine compartment and into the stream
>of cooler air under the car. I've decided that I will use a "backup"
>electronic fuel pump plumbed into the fuel line near the gas tank and
>out of sight on my TD restoration. I'll keep the SU for looks, but my
>experience with point-driven fuel pumps has led me to distrust all of
>them, no matter the manufacturer.
>
>David Littlefield
>Houston, TX
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