The most elegant method I've seen to accomplish this is to attach a
water manometer to the spark plug hole.
As you approach TDC the water in the manometer rises and then stops and
recedes as you pass TDC.
When you are near, but not at, TDC mark a spot on the pulley and note
the level of water in the manometer.
Turn the crank past TDC until the water level in the manometer comes
back to the same level.
Mark the pulley at that point. TDC will be half way between the marks.
Bill Lawrence
On Jun 18, 2004, at 3:30 AM, Keith Turk wrote:
> Somebody needs to help me with one part of this set up.... I don't know
> exactly where the Valves are in a 3000 motor... but here's the answer
> to
> finding TDC on a Small block Chevy...
>
> I built a special spark plug... it's got a threads down the center
> rather
> then ceramic material.... I then threaded a bolt into it... the bolt
> itself
> has a rounded end on it...( take an old plug put it in a vice and start
> being brutal to it... you can get the center materials out )
>
> So what I do is back all the valves off so the springs don't interfer
> with
> me rotating the engine... and remove all the spark plugs... Then
> rotate the
> engine to around TDC...( stick your finger over the hole as your
> turning it
> and feel it build air pressure ).... or stick a straw down the center
> of our
> special plug....and watch it rise as the piston comes up. Then I
> stick my
> bolt in until it touchs the top of the piston... and mark the crank
> pulley... next you rotate the engine backwards... VERY carefully until
> the
> bolt hits again....and mark the pulley again.... there should now be
> two
> marks on the crank where your bolt touched the top of the piston....
> the
> center of the two marks is TDC... exactly...build yourself a timing
> pointer
> that is stablized off two bolt holes and away you go... you can do the
> math
> to figure out degree's before and after TDC or you can buy a timing
> tape
> from your local speed shop based on the pulleys diameter... ( they
> come from
> MSD )
>
> Hope that helps...
>
> Keith
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