Engine/Transmission (1994 - 1998) Top Dead Center?

[CRohwedder]

Whats the best way to Get the motor to TDC when the timming pin is broke? I hear you can go by the valves, but am not sure how to do it. Thanks for the help.

 

[JFlagg]

Cory, did you break your truck already?

 

[JGK]

You'll need to make a pointer for your harmonic damper using a piece of wire like coat hanger wire or gas welding wire. Fasten it either below off an oil pan bolt or above under one of the speed sensor retaining nuts.



You'll need to bar the engine over both forward and backward.



Now remove the valve cover from #1 and bar the engine until both rockers are loose. Watch their action and you can tell when the intake opens then closes (bottom of intake stroke). The next half rotation is the compression stroke. At that point you're somewhere near TDC. Back the engine up at least a quarter rotation - neither valve should move. Loosen and back the nut for the exhaust valve lash adjustment off about 5 or 6 turns. Now screw the lash adjuster down 4 turns once it contacts the valve. That pushes the valve down a bit. Rotate the engine forward with the barring tool slowly until feel the piston snug up agains the valve. It helps to have someone put their finger firmly on the adjuster to feel when the piston starts pushing on the valve. Be gentle but firm and don't force it. Now mark damper at your pointer. You can put a piece of masking tape on the damper edge and use a pen to mark it.



Now bar the engine BACKWARD about 2/3 to 3/4 rev until the piston bumps up against the valve again. You're rotating back into the intake stroke so your intake valve will open as you come up against the exhaust valve. Mark the damper again at your pointer. Rotate forward until you can see both marks from underneath (that's where you have the best access). Measure the distance between the marks - this will be the short distance between them. Be exact - use a metric scale. It should only be about 4 inches (100 mm plus/minus) between them. Mark the damper with a scratch awl at this point.



Back the lash adjustment screw for the valve off completely so the valve comes back up and seats and rotate the engine forward until your new permanent mark is lined up with your pointer. You're at TDC, closer than the pin will ever get you.



Reset your valve lash on the exhaust and replace the cover.



-Jay