How to use a TDC tool

[Guest]

I usually can figure out how to use a tool but this one has me stumped.

How do you use a TDC tool like this one? Does it "click" when it hits TDC like an edge finder for a mill does when the edge is ID'd?

[tom203]

Does it have any LED's and a battery? Or lasers?? What's wrong with a dial indicator?

[JTGS850GL]

You would use it in conjunction with a degree wheel. You screw the tool into the sparkplug hole. Slowly turn the crank until you hit the stop. Record the reading on the degree wheel. Turn the engine in the other direction until you hit the stop. Record the reading on the degree wheel. Divide the readings in half and you'll know exactly where TDC is on the wheel.

Edit: The tool comes in three sparkplug sizes 10mm, 12mm and 14mm.

[trippivot]

the trick is to have the exact number indicated by your pointer on the degree wheel at the point when the positive stop contacts the piston in both directions. it stops at 53 in Clock wise and it stops at 53 in counter clock wise ... then you absolutely know TDC is TDC .

the math method example -- 125 / 34 --- add the two indicator readings / divide by 2 / and move the wheel half the product ... check re-check, check

[Kyler]

thanks! that makes sense.

[dennis]

I have a question,The marks on the ignition plate are they not accurate enough to find TDC ?

[stetracer]

I have a question,The marks on the ignition plate are they not accurate enough to find TDC ?

Not really. I always set up a degree wheel for cam and ignition timing

[Big Jay]

I have a question,The marks on the ignition plate are they not accurate enough to find TDC ?

Not for degreeing cams, or checking for a twisted crank.