Top Dead Center Question
Thread Starter
Safety Car
Joined: Aug 2005
Posts: 3,968
Likes: 867
From: Tulsa Oklahoma
Top Dead Center Question
What's the easiest/best why to find TDC on the COMPRESSION stroke for the #1 cylinder WITHOUT having the timing chain/sprockets visible?
TIA
Rick
TIA
Rick
Last edited by rikhek; Sep 6, 2007 at 02:41 PM.
6th Gear
Joined: Aug 2007
Posts: 6
Likes: 0
From: Race City USA NC
What motor, LS1, LS6? Is the motor in the car our out ? Are the valve covers on? Which cylinder do you want TDC for ?
One way is to get a view of the balancer and turn the motor until the timing indicator is at the 0 Degree mark. This will give you TDC for the #1 Cylinder.
Another way is to use a dial indicator on the intake or exhaust valve for the cylinder that you are trying to find TDC for, if you know for sure that the Camshaft is installed strait up and not advanced or retarded.
Another way is by intalling a piston stop into the spark plug hole for the cylinder that you are trying to find TDC for.
One way is to get a view of the balancer and turn the motor until the timing indicator is at the 0 Degree mark. This will give you TDC for the #1 Cylinder.
Another way is to use a dial indicator on the intake or exhaust valve for the cylinder that you are trying to find TDC for, if you know for sure that the Camshaft is installed strait up and not advanced or retarded.
Another way is by intalling a piston stop into the spark plug hole for the cylinder that you are trying to find TDC for.
6th Gear
Joined: Aug 2007
Posts: 6
Likes: 0
From: Race City USA NC
Sorry, reading too fast, I see that your looking for the #1 cylinder. 
- If the motor is out of the car, the best way is with a piston stop installed in the #1 cylinder spark plug hole. Mount a degree wheel to the crankshaft and a pointer to the engne block. Remove the rocker arm and pushrod from #1 cylinder. Install a TDC stop in the spark plug hole of #1 cylinder.
To locate top dead center, rotate the engine until the piston contacts the TDC stop ( do this lightly and by hand with a socket on the harmonic Balancer bolt. DO NOT TURN THE MOTOR WITH THE STARTER) I suggest pulling the plugs out of all the cylinders as it will be easier to turn the motor by hand with the plugs out. Mark the degree wheel at the pointer. Now rotate the engine in the opposite direction until the piston stops. Make another mark on the degree wheel at the pointer. If the degree wheel is properly located, there will be an equal number of degrees on on both sides of TDC on the degree wheel. If an unequal number of degrees exists, the degree wheel will have to be relocated. For example, if you come up with 34 degrees on one side and 30 degrees on the other side, the wheel will have to be moved 2 degrees to correct the misalignment. Once the degree wheel is aligned, remove the marks that you made and remove the TDC stop.
- Another way if the motor is in the car, is to use a dial indicator on the #1 intake valve. I need to know camshaft specs to be sure to give you the right info here though.
- If the motor is out of the car, the best way is with a piston stop installed in the #1 cylinder spark plug hole. Mount a degree wheel to the crankshaft and a pointer to the engne block. Remove the rocker arm and pushrod from #1 cylinder. Install a TDC stop in the spark plug hole of #1 cylinder.
To locate top dead center, rotate the engine until the piston contacts the TDC stop ( do this lightly and by hand with a socket on the harmonic Balancer bolt. DO NOT TURN THE MOTOR WITH THE STARTER) I suggest pulling the plugs out of all the cylinders as it will be easier to turn the motor by hand with the plugs out. Mark the degree wheel at the pointer. Now rotate the engine in the opposite direction until the piston stops. Make another mark on the degree wheel at the pointer. If the degree wheel is properly located, there will be an equal number of degrees on on both sides of TDC on the degree wheel. If an unequal number of degrees exists, the degree wheel will have to be relocated. For example, if you come up with 34 degrees on one side and 30 degrees on the other side, the wheel will have to be moved 2 degrees to correct the misalignment. Once the degree wheel is aligned, remove the marks that you made and remove the TDC stop.
- Another way if the motor is in the car, is to use a dial indicator on the #1 intake valve. I need to know camshaft specs to be sure to give you the right info here though.
Thread Starter
Safety Car
Joined: Aug 2005
Posts: 3,968
Likes: 867
From: Tulsa Oklahoma
LS1 engine is in the car..... Also, I don't have a degree wheel/pointer, piston stop, etc.
I'm installing new pushrods so valve covers will be off.
I'm installing new pushrods so valve covers will be off.
Last edited by rikhek; Sep 6, 2007 at 01:33 PM.
