Brandonb_05

Disconnect coil. Disable fuel. Put a remote starter button on. Remove your first spark plug, put your finger near the spark plug hole bump the starter button until you feel a puff of air come out of spark plug hole. Then you can use a drink straw in the spark plug hole to find true TDC by turning the engine over with a ratchet, when the straw gets to its highest point your at TDC. This Process might take two people one to turn the motor over while the other watches the straw. Use a good 6-point socket on a half inch drive ratchet on the crank bolt, you might have to remove the accessory pulley to allow the socket clearance to get on crank bolt. If everything is fine in the engine, the bolt won't strip out.

Brandonb_05

Black Baja's way is a pretty good way, probably take less time as long as you can get your valve covers off with the exhaust on.

HaxbySpeed

That way will work, but you will be measuring leak down at bottom dead center instead of top, and any piston rock can effect your reading. TDC is more of a pain in the butt, but it measures how well you're sealing in a more critical area.

Brandonb_05

Are you saying my way is going to be BDC?

HaxbySpeed

No, Blackbaja's

buck35

This is interesting and I never knew how to perform this test, so do you use the breaker bar to hold it at tdc?

HaxbySpeed

When it's truly at TDC it will not try to rotate because it's pushing straight down. Trying to hold it with a bar can be exciting, and or dangerous.

buck35

Gocha, thanks for that little tidbit!

Brandonb_05

I have never heard of having to hold a breaker bar on the crank, but like haxby said you shouldn't have to. You could hold a dollar bill at the exhaust pipe to see if you have a Burnt exhaust valve, the dollar bill will be sucked back to the exhaust pipe. Just joking. I've heard a lot of older car guys use that method.

GLENAMY 242SS

iTrader: (1)

Reading this post i just devised a simple cheap tool that will guarantee tdc any cyl you desire no crank position cumpass, no removing parts, no straws, no second person, no bs.
This will only work with dizzie motors.
Requires cheap self powered conuinity tester.
2 ea plug connectors 1 connected at each end of tester.

Procidure:
Rotate engine to tdc #1 mark on ballancer ( #1 verified by rotor position).
Loosen dist. And retard.
Remove coil & #1 plug wire
install tester on coil tower and #1 tower on cap.
Advance dist until light just comes on.
Lock dist.
Now tdc can be found on any cyl by moving the tester "plug wire" to desired cyl and rotate motor until light just comes on.
You are at tdc for desired cyl.
Dont forget to reset base timing when done. If you are creative you could use this initially to mark current timing on crank and return to that baseline when completed, virtually eliminating the need for dynamic re-timeing of dist.
Call me an idiot but this is the way i will try it next time.
Hope this makes sense and good luck.