Timing Question

M

Maurer1929

Member
Hello,

When the timing pin is inserted at TDC, should be #1 piston be level with the top of the cylinder or a few mm above it. Mine is a few mm above it?

Thanks

Rick
 
TDC simply means it is at the top of its stroke. Be sure to measure how far above the deck the top of the piston is and make sure you are not going to have head clearance problems. You will also have to measure the head and allow for the compressed thickness of the head gasket. Larry Brumbfield posted the compressed thickness of the gasket afew times, so maybe someone will stop by with proper measurement. Rod
 
take all the spark plugs out and use a flashlite and you will see #1 piston above deck and grind a point on timing pin so that it fits snug into timing hole as you hand crank and putting pressure on pin as it will slip into hole.
 
I think Marco posted that specified piston protrusion was .017...obviously, milling and stack up of piston tolerances, babbitt work, and such could have altered that, so measure and make sure there's no chance of reaching the cylinder head, though that is pretty unlikely.
 
I have made the mistake of inserting the pin but having it slide out so that it feels like it is sitting on the rim of the access.
So now I watch for movement on the pin as well as feel for the hole.
 
HARLEYJOE said:
take all the spark plugs out and use a flashlite and you will see #1 piston above deck and grind a point on timing pin so that it fits snug into timing hole as you hand crank and putting pressure on pin as it will slip into hole.
Click to expand...

I agree.

When setting up my engine, no matter how careful I was, I could not really feel the timing hole in the cam gear with the pin. I ground the pin to more of a point and rounded the very end a little, Now, it falls right in the hole. Makes things a lot easier. Just be sure to turn the engine
V E R Y S L O W L Y when finding the timing hole.

My experience,

Chris
 
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I use a stubby Phillips screwdriver to find the recess in the timing gear. It gives me a better "feel" and I don't have to grind the pin.
 
I establish where #1 TDC is with the pin and the piston, then notch the pulley and put a matching mark on the block. Works for me.
 
Tighten fan belt so that you can rock the crank with the fan blade.

Remove plug #1

Insert pinkie, feel for the TDC of the piston (reach to the Port side of the head, you don't want to be timing on the valves on the Starboard side of the head) Yep, been there, done that.

If you have a mechanically inclined child, this is a wonderful lesson on what really happens inside an engine. Please make sure to disconnect the battery before doing all of this as we need all of the mechanically inclined children to have intact fingers as they grow older. Most don't care about engines, they are only good for getting them home to their video game consoles.

Feel for the first instant that the piston begins it's downward movement (on bang cycle, not suck cycle), rotor should be at about the 4 pm position when viewed from the starboard side of the engine.

Take a cold chisel to the TDC of the crank pulley, paint some White Out into the chisel mark.

Make sure you look directly down on the mark, not from the side (problems of parallax). You can make a pointer from some spare sheet metal and attach it to the head so that it points to the White Out.

Leave the pin screwed into the timing cover and explain to civilians that Henry designed his engines with a wonderful device for setting TDC that even a non-mechanic/non-farm boy could master.

If you ever have to take off the head, use this same procedure to set TDC without pinkie.

Remember that in the genius of the "A" Engine, the TDC #1 piston is already a few degrees past the "TDC" of the crank, so that Piston TDC, even with a retarded spark setting, is ready to unleash 40 raging horses on the world.
 
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When installing a timing gear, I always make the dimple a little deeper by hand with a drill bit. Makes finding it with the pin much easier.
 
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