Hi Barney;
You said: "Getting the drive gear in 180 degrees out of position is actually
fairly
> common, as the shop manuals are somewhat misleading on the assembly
> instructions (if you're not paying attention)."
That's not the only problem. On my recent rebuild, before disassembly, I
marked EVERYTHING externally to be sure I got it back together absolutely
the way it came apart. But you can't mark the position of the drive gear
with respect to the camshaft. So you have to rely on the hazy instructions
about how to assemble the thing so it rotates to about the 2:00 position,
etc.
When I went to start that baby up I discovered after about 10 minutes that
the gear was in there likely "one tooth" out, not 180. By rotating the wires
one position counter clockwise, and rotating the dizzy cc about 45 degrees,
everything snapped to attention and now it runs like a bandit.
Upon reflection, and looking at some photos of allegedly original motors, my
dizzy is now where it belongs, and it was incorrect when I disassembled it.
Some previous owner must have assembled the drive gear slightly off target.
Another unknown variable in the world of dizzy assembly!
Dave
After reflection
----- Original Message -----
From: "Barney Gaylord" <barneymg@ntsource.com>
To: "Andrew B. Lundgren" <lundgren@byu.net>; <mgs@autox.team.net>
Sent: Wednesday, July 04, 2001 3:35 PM
Subject: Re: timing facts
> At 10:56 AM 7/4/2001 -0700, Andrew B. Lundgren wrote:
> >Oh it'll go in backwards alright. I have done it, without forcing it, on
> a '77 engine.... Wouldn't start, but it did sputter...
> >
> >On Wed, 04 Jul 2001 09:14:18 -0500, Barney Gaylord wrote:
> >>.... the dizzy drive is keyed off center at the connection between the
> dizzy and the drive gear, ....
>
> Well, since the distributor shaft with the drive dog on it cannot be
> assembled backwards with the drive gear, that would mean you either had
the
> drive gear in 180 degrees out of position, or the distributor body rotated
> 180 degrees out of position, or the HT wires were installed on the wrong
> plugs.
>
> Getting the drive gear in 180 degrees out of position is actually fairly
> common, as the shop manuals are somewhat misleading on the assembly
> instructions (if you're not paying attention). One problem is
> understanding "the larger offset uppermost", and whether this refers to
the
> location of the slot or the size of the lumps on either side of the slot.
> But even when you get that figured out, there's another possible "gotcha".
>
> Instructions for installing the timing sprockets have you set the
> crankshaft key at TDC, and the camshaft key at aproximately one o'clock,
> and assemble the sprockets with the punch marks aligned. What it casually
> does not mention at that point is that the cam is indexed with the #4
> cylinder on the compression stroke, not #1. If you then proceed to
install
> the distributor drive gear as prescribed it will be 180 degrees out of
> place. You have to pay attention to the first sentence in the
instructions
> for installing the distributor drive gear: "Turn the engine until No.1
> piston is at T.D.C. on its compression stroke".
>
> Barney Gaylord
> 1958 MGA with an attitude
> http://www.ntsource.com/~barneymg
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