Dimple Hunter

E

Epetek1

Senior Member
timing my A I am having trouble finding the dimple in the timing gear as the engine is tight and hard to turn. Stupid question. If I remove spark plugs making the engine easier to turn is there any reason this won't be a easier way to find it. Thanks for any help. Pete
 
Epetek1 said:
timing my A I am having trouble finding the dimple in the timing gear as the engine is tight and hard to turn. Stupid question. If I remove spark plugs making the engine easier to turn is there any reason this won't be a easier way to find it. Thanks for any help. Pete
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No Pete, nothing wrong with that.

Generally speaking, it is easier that first time to place the gear selector in high gear and roll the vehicle back & forth (-which rotates the engine) to find the dimple. Even if you can get close, that is fine. If the engine ever starts, then after a minute or two of running when it cools to room temperature, it should be easy to rotate with the hand crank where you can re-adjust the timing and find the dimple much easier.
 
thanks useful advice, appreciated. this is a 1930 standard roadster stored in a garage since 1987. It starts and runs but can't get the engine to run with throttle floored, suspect timing, so i am retiming it and hope that solves the problem. Pete
 
`If you have not moved the cam on dist. and engine was running you can take cap off and turn engine so rotor points to no. 1 and then move crank back and forwards to find dimple , might save you a little turning
 
What I do is forget the timing pin. I remove the #1 spark-plug and hand crank the engine over until you see the intake valve close and the piston comes to TDC. You can easily see the intake valve and the top of the piston with a flashlight. You then know the timing can be set in the distributor perfectly.
 
Real good advice about turning rotor to #1, then start looking. I just found that I can use a cheap magnifying mirror and a bright little flashlight to actually see into the pin hole. You can see exactly when the dimple is centered in the hole. I found this more accurate then feeling with the pin.
 
Sometimes a light and mirror can find the dimple.

Sometimes grinding the pointer to more of a point can find the dimple. A small phillips screwdriver can do the same thing.
 
An old school method for this is to get the valves on # 4 "rocking".
To find TDC on number one, it is easy to find TDC on number 4. Cylinders 1 and 4 move up and down in unison so both are at the top at the same time. One is at TDC at the end of the exhaust stroke, the other at TDC at the end of the compression stroke. If you look at the valve timing data, you will see that when the piston on any cylinder is approaching the top of its exhaust stoke, the inlet valve starts open 7 1/2° before the top and the exhaust valve starts to close 4 1/2° after. Rotating the engine back and forward, you will see one open a little as the other closes a little - they are rocking.
If you rotate the engine till both are open an equal amount, you are close to TDC. If you stop when the inlet is slightly more open than the exhaust, you are very close - close enough to set the timing and close enough that the pin will drop straight into the timing gear dimple.
I always time my engines this way when I am assembling them. It's easiest when the head is off.
 
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