Verify Top Dead Center Accuracy Using a Piston Stop

Verifying that my new balancer and timing marker are accurate to true top dead center using a piston stop. Same procedure can be used to verify an old balancer hasn’t “slipped”. This is a 390 Ford, but the process is the same for just about anything.

[@TheGrumpyGangster]

Hey, thanks for this man, I am working on a 64 Monterey, it is a 4-door but it is beautiful! The interior is pristine and it still has the paint/ coating on the underside! I am working on making it as smooth of a driver as possible, the engine is in perfect condition but the carb is completely messed up. I have been working on fixing it and just finally today I got it finished! Save a few adjustments, I am done working on the carb!🥳
While testing it and running through everything, I took it to a quiet stretch of highway, and planted the gas, I hit just about 102 mph! I can't wait to see more of your merc, it looks like tons of fun and is very helpful for referencing to! Thank you!

[@JalopyJockey]

Hey, I appreciate it. You don’t seem very grumpy at all! Have you seen Carburetor Mike’s carb rebuilds on UA-cam? He has great videos rebuilding 2100 and 4100 Autolites. These do seem to like a bit more timing than the Ford book says. Help with off idle transition. Also, need the accelerator pump to hit immediately with throttle movement. Join the 1964 Mercury Full-size fans page if you have Facebook.

[@ayyy9017]

How much do you need to thread it into the plug hole? All the way at the bottom?

[@JalopyJockey]

I had to thread it in all the way to make contact with the piston. As long as it does stop the piston, it’s good.

[@ayyy9017]

@@JalopyJockey thanks so much man🙏🏽 most creators won’t reply this late thanks bro 💯

[@ayyy9017]

@@JalopyJockey also my piston basically reaches the very top so do I need to have it stopped half way down? Or can I just stop it near the top? Thanks

[@JalopyJockey]

@@ayyy9017 it should be near the top. 10-15° from top probably

[@stephen295]

WHY DOES THE CENTER HAVE SCREW DRIVER SLOT ?

[@JalopyJockey]

You can turn the stop up and down, depending on how much reach into the cylinder you need. I had to have it nearly all the way down for the stock heads

[@stephen295]

​@JalopyJockey thanks ,so turn eng CW until close to 0 ,adjust center stud all the way down ,then turn eng until it touches piston . Correct , then CCW rotation an divide marks 1/2 for TDC. I just couldn't understand why it's adjustable but I guess with different heads ,it could be different lengths. I remember using a spring loaded one ,you just watched the tip as it rised/ lowered like a dial indicator ,but where the spark plug goes .thanks