Finding TDC

Hi folks,

I have a 1955 M38A1 that I wish to find TDC. I want to time my engine, and when I use the original notches, the engine runs poorly. I believe they may not be accurate, and wish to find TDC to confirm this. Does anyone have any tips or tricks to find TDC on the F head engine?

I'm a little slow at this, so please keep it simple for my okay?

Thanks for any and all info, it is appreciated!

Chris
Cortland ,NY

 

Hi Chris,

I would pull the number one spark plug first. Then note where number one plug wire is on the distributor cap and pull the cap off. Then rotate the engine forward until you get close to the rotor pointing to the number one wire location on the cap. Get a drinking straw and lower it in the plug hole and watch the straw while you turn the engine. At the highest point of travel, you should have TDC. If you don't want to pull your cap, then you can place your finger over the plug hole and feel for the compression to blow by your finger. That should get you close.

Good luck,

Dan

 

Thanks Dan, I'll give it a shot. I was thinking of using a unsharpened pencil with notches marked in permanent marker but I think a straw may work cleaner. I was a little worried that paint from the pencil may flake off into the engine.

Thanks for the tip! It is very much appreciated!!

Chris
Cortland, NY

 

You're welcome. Let us know what you find.

Dan

 

If it is the original engine, you should have timing marks on the flywheel that show through a hole the size of a halfdollar just above the starter motor. Those 'should' be accurate. but may not.monkeys

 

Many unanswered questions with old Jeeps. I "think" I have the orig engine and I have no such hole above the starter, nor can I find a ref to same in the Mil manual .... though I could have been drunk when looking at both