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[oletrucks] Misfire Misdiagnosis

To: "'Kevin Lake'" <lakek@oit.edu>, "'Wayne Osborne'" <wcosborne@inetnow.net>
Subject: [oletrucks] Misfire Misdiagnosis
From: Tom Burt <tburt@hirose.com>
Date: Mon, 5 Apr 1999 10:50:54 -0700
Wayne/Kevin/oletruckers,

How my truck was blessed on Easter Sunday: A sucess story to be shared with 
the oletrucks list.

Easter Sunday I had to deliver four sheets of plastic lattice to my 
brother-in-laws 25-miles away.  Being my wifes brother, she insisted that I 
take the '57 truck.  I resisted at first, but then yielded to her request.
En route I nearly chipped a tooth from gritting my teeth while the truck 
repeatedly misfired.  We finally made it there without breaking down.
While visiting, the neice's boyfriend volunteered to take look under the 
hood.  His observations were as follows:

1.) I had mounted the ignition coil (going clockwise) 135 degrees from 
verticle.  This was for two reasons: so that the coil wire would reach the 
distributor and so the bracket be mounted on a flat surface on the firewall 
(recall curved depression feature on cab firewall).  I was told by 
autoparts folks that the coil is sealed and that orientation was not a 
problem.
His Response: Coils must be mounted vertically so that the oil inside 
provides a sufficient dielectric.  Any mounting otherwise will weaken or 
damage the coil windings.

2.) The only ground he observed was a strap running from the 
tranny/bell-housing to the cab.
His Response: To ensure a good ground, straps should be attached from the 
engine block to the frame.  The webbing on the cab to frame coupled with 
aluminum from bell-housing were two points that could concievably cause 
poor grounding.  Poor grounding may cause points to burn faster and HEIs to 
breakdown.

Turns out, this guy works for Mallory and knows the product pretty well. 
 So while there, I gave it a try and reoriented the coil to a verticle 
position.  I took it for a test spin and...the misfire disappeared.  As for 
the grounding, I plan to add a new strap as suggested from the block to 
frame.  He also asserted that for ignition systems GOOD WIRING IS A MUST! 
 Something I have to reflect upon since my truck was wired by the PO!

Tom B. 57 Stepside 3200


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