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Re: BJ8 gas gauge

To: Alan F Cross <alanx@proaxis.demon.co.uk>
Subject: Re: BJ8 gas gauge
From: John Harper <AH@jharper.demon.co.uk>
Date: Tue, 28 Mar 2006 13:44:19 +0100
Alan

I am going to repeat a warning that I done a few times before over the 
years.

It is not that I can prove a risk it is just that I wish to warn readers 
that there might be one.

The tank units on our cars and many others fitted to cars of the same 
age as ours are not sealed against petrol entering the chamber in which 
the resistor and slider are located. Indeed the sealing is in the lid 
and around the terminal screw. Hence it is possible that an explosive 
mixture could build up in this chamber.

I once went to a demonstration where a spark was made in an explosive 
mixture but this did not cause an ignition with the initial low spark 
level but did once the amount of electrical energy reached a certain 
level.

We have to assume the Smiths when they designed this system were happy 
that the system was safe.

However when one adds a large source of additional energy such as a 'fat 
electrolytic capacitor' how is one to know without carrying out tests 
whether or not a new risk of explosion has been introduced.

I cannot say that there is an increased risk by modifying a proven 
system; it is just that I would not personally take this risk or 
recommend it to others.

This is perhaps the third time that this issue has come up. On previous 
occasions others have added lurid tales of serious fires. Perhaps they 
will do so again.

All the best

>Not done this, but has anyone tried putting a fat electrolytic 
>capacitor across it, to smooth things out?
>
>
>
>In message <000001c637c0$8c9f81b0$6401a8c0@billea0d96eb39>, Bill 
>Browning <gbrowning@carolina.rr.com> writes
>>Hello Healey listers:
>>
>>Any secrets  or pearls out there on BJ8 gas gauge accuracy? My gauge goes to
>>full when tank is filled up, then after about 20 miles it goes to 1/2 full
>>and the needle starts going "haywire" gyrating like crazy back and forth,
>>then after a few more miles, it goes to Empty even though the tank if close
>>to 3/4 full.
>>
>>I have been just zeroing the odometer when filling up and watching mileage
>>to determine amount of gas. I've gone thru this before on a couple other
>>BJ8s in the past, new sending unit, adjusting float in tank, etc spending a
>>lot of money, and it went back to doing the same thing.
>>
>>Would appreciate any magic from the list
>>
>>Thanking you in advance
>>
>>Bill Browning
>>Charlotte, N.C.
>>

-- 
John Harper




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