mgs
[Top] [All Lists]

Re: timing facts

To: "Evangelos G. Makris" <egmakris@otenet.gr>, mgs@autox.team.net
Subject: Re: timing facts
From: Barney Gaylord <barneymg@ntsource.com>
Date: Wed, 04 Jul 2001 09:14:18 -0500
At 04:35 PM 7/4/2001 +0300, Evangelos G. Makris wrote:
>Please tell me if the following is correct:
>
>1. If your engine works OK as it is and you remove and re-install the
distributor 180 degrees out, it won't even start.

True.  But on an MG that is not easy to do, because the dizzy drive is
keyed off center at the connection between the dizzy and the drive gear, so
it can'r be installed backward.  The only way to change the indexing of the
distributor rotor is to remove the drive gear from the block, rotate it and
reinstall it.  Or maybe remove the drive dog from the bottom of the dizzy
and install that backwards.

>2. The action in the previous sentence is equivalent to swapping HT
sparkplug wires 1-4 and 2-3 without touching the distributor in the first
place.

True.

>3. When the woodruff key on the crankshaft is at 12 o'clock then pistons
#1 and #4 are at TDC but only one of them in its compression stroke.

True

>4. If you don't set the dots on the crankshaft & camshaft gears facing
each other when replacing the timing chain the engine won't start at all.

Most likely true, as the camshaft would not be timed correctly.

>5. If the timing cover has the timing marks at the top (top viewing) then
the correct crankshaft pulley must *also* have its timing notch "near" the
top when the groove for the woodruff key is at the top (12 o'clock). In
other words the timing notch and the key groove must be just a few degrees
"away" from each other on the pulley.

True.  But having the incorrect pulley with timing marks in the wrong place
won't keep the engine from running, as long as the timing is otherwise
correct.

>I may go nuts but in the end I'll find out what's wrong...

>Evangelos
>73 BGT, 66 Sprite, both engines working fine but their timing notches way
away...

On engines with a harmonic balancer type crankshaft pulley, there is rubber
vulcanized between the hub and the outer ring.  Sometimes the rubber
deteriorates and breaks loose from one of the metal parts, allowing the
outer ring to rotate in relation to the hub.

If you have a later type timing cover with the pointer at the top, and an
earlier type crankshaft pulley, then the timing mark on the pulley could be
near the bottom of the pulley when you get the spark, so not near the pointer.

So just where is the timing mark, and how far away from the pointer?

Barney Gaylord
1958 MGA with an attitude
    http://www.ntsource.com/~barneymg

///
///  mgs@autox.team.net mailing list
///  (If they are dupes, this trailer may also catch them.)


<Prev in Thread] Current Thread [Next in Thread>