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Re: Backfire

To: JedPiper <JedPiper@earthlink.net>
Subject: Re: Backfire
From: Wally Teto <monadnoc@wgserv.crystal-mtn.com>
Date: Mon, 18 Aug 1997 03:05:54 -0700
JedPiper wrote:
> 
> Wally -
> 
> Regarding your rough running B.  Is there a chance that the vacuum advance
> on your distributor has croaked?  The vacuum unit is the round flat object
> mounted on the side of your distributor and it may be that the diaphram
> within the advance has given up the ghost.  Try disconnecting the vacuum
> hose from the advance while your car is running; if you notice a change in
> performance the advance is probably functioning, if not, it may be time for
> a new advance.
> 
> If the advance appears to be functioning you might try advancing the timing
> using the fine adjustment wheel located on the opposite side of the advance
> unit of your 25D4 distributor.  Sometimes this slight adjustment will
> smooth things out a bit.
> 
> Of course your problem may not be related to the advance at all, but it
> won't cost you anything to check it out.  Good luck.
> 
> Jed
> 76B
> et. al.

Thanks Jed, I had not thought of that.  I did advance the timing from
the 10 degrees to 15 degrees (both static) with no apparent change.  But
while doing so (I did it by rotating the dizzy) I noticed that the
vernier adjuster only has a range of about 10 or 15 clicks.  I was under
the assumption from the Haynes book that 55 clicks was about 5 degrees. 
No way can I get this much rotation out of mine!  I have another
distributor on my donor car and may just swap them around in the next
couple of days to see if there is any improvement.  BTW when I did
remove the vacuum line from the distributor, the idle speed increased by
a few hundred RPM...significant??

Wally
71 MGB



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