[Healeys] Swapping distributors

[Bob Spidell]

I'll repeat a story I've told before, just for 'color.'

I once knew an aircraft mechanic who used this 'technique' to find TDC 
on an aircraft engine. He bumped the starter just a tad too much and 
ripped all the flesh off the end of his thumb (to be fair, aircraft 
spark plugs and hence their holes are a bit larger than auto plugs).

Bob

On 6/15/2023 9:19 AM, john harper wrote:
> I have an interesting story along the same lines where a distributor 
> worked loose and jumped out of mesh. This had an early single bolt 
> fixing to the block and these were prone to slipping.
>
> The timing was therefore completely out and I needed to get the 
> distributor lining up with the number one cylinder. I then used an old 
> trick to get the engine on TDC on the compression stroke. The trick is 
> to remove the spark plug from the number one cylinder and place the 
> thumb over the hole. After a few attempts engaging the starter it was 
> possible to judge when to stop cranking on the compression stroke. 
> After replacing the plug and making sure that the distributor rotor 
> was pointing at the correct plug lead the distributor was replaced: 
> allowing for the spiral action as it was inserted. Fortunately, the 
> engine then started and approximately the correct timing was 
> managed by turning to get the best idle.
>
> This got me home
>
> All the best
>
> On Thu, 15 Jun 2023 at 12:11, Simon Lachlan via Healeys 
> <healeys at autox.team.net> wrote:
>
>     You may recall that I asked if there was an easy method of
>     swapping distributors ie doing it at the roadside without being
>     overly troubled by timing issues.
>
>     Replies varied.
>
>     In the end, I bought another base plate which I put onto my spare
>     Lucas (points).
>
>     I marked the base plate of the 123 and the top of the turret upon
>     which it sat. ie so there was a datum(?) point to which to return.
>     Used a Dremel.
>
>     I did the same for the Lucas after getting it timed. I made the
>     marks on the other side ie to the left of the distributor.
>
>     I removed the Lucas, located the 123 back on its mark and, hey
>     presto, it works.
>
>     One surprise…in my ignorance, I thought that, if the 123’s rotor
>     arm faced at, say, 12 o’clock, then so would the Lucas’. Both
>     could only align one way with their gears’ physical connection to
>     the turret upon which they sit?? Well, yes, the gears could only
>     align identically but the rotor arms were about 30° out. ie  123’s
>     at 12 o’clock and the Lucas’ at +/- 2 o’clock. Both are working at
>     15°/idle…….Who’d have guessed it?
>
>     One other thing…..I was going to put my Pertronix back into the
>     Lucas. Can’t have two electronic ignitions fail in one day, can
>     you? However, it seems that I’d put points back in because I’d
>     lost the collar (“magnetic ring”). Actually, I forget what I did,
>     but it’s gone anyhow. Like my memory perhaps. My unit is marked
>     LU-165. I don’t suppose anyone has a spare one??
>
>     Simon
>
>
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