Re: [alfa] Dial Indicators for Finding TDC

[Jon Pike <jhpike@xxxxxxx>]

> The way to do it, probably MORE accurately than WITH a cheap dial
> indicator, LET one without a good mount:
>
> Make some sort of a ridgid extension for an old spark plug--long enough to
> reach the top of the piston when it is a bit (maybe 1/8") below TDC when
> the assembly is screwed snugly into the spark plug hole.
>
> Rotate the engine forward until the piston contacts the stop. Mark the spot
> on the front pulley where the piston contacts the stop.
>
> Rotate the engine backwards until the piston again contacts the stop. Mark
> the spot on the front pulley where the piston contacts the stop.
>
> REMOVE the stop !!! 
> Halfway between the two marks you made on the front pulley is true TDC.
> Mark it, adjust the pointer to match it, whatever you choose to memorialize
> your results.
>
> Greg  (nothing wrong with hillbilly approaches as long as they WORK,
> accurately !!!)
Wassamatter, you don't like my Xacto Knife Handle Extension???  ;-)

Not to start an argument Greg,  but I was getting (a lot) better than 
half a thousanths repeatablilty on different tries of the TDC point on 
The Kludge(tm)...  As long as it didn't get bumped, it was about as 
stable as you could expect it to be if attached with bolts.

Probably close enough for Rock and Roll 'n Government Work..   I'd guess 
we probably get similar accuracy, between accurately hitting the minimum 
distance reading,  and exactly dividing the distance between both stop 
points.

Now what I'd really like is a easy way to measure cam lobe center 
points, or valve opening points. 
Centerline has a print out protractor that you put in your front cam 
bearing cap and check and/or recalibrate your cam timing markers,  
anyone use this or have idea of it's accuracy?

Jon and Marcia
77 Spider
Irvine, CA
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