Can someone fill in the blanks for me?.......At TDC on #1 the #1 cylinder will have both its valves closed and cylinder #__ will have its valves________. Thanks guys.

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92Z28
89GTA

 

6 open

 

Both intake and exhaust open?

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92Z28
89GTA

 

C'mon now!! Think about it!!!

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1987 GTA L98 MD8
355, TFS Heads, LT4 Hot Cam
My GTA

The Minnesota F-body Club

 

it's not really relevent what #6 is doing.

If you at TDC on the compression stroke, #1 valves will both be closed.

If you are at TDC on the exhaust stroke, #1 exh valve will be open (possibly the intake will be open a little too)

 

RB's words:Find #1 TDC by looking at the piston; rotate the engine slowly toward that point while watching the #6 rockers; if the #6 exhaust is closing as the piston is approaching TDC, then you're at #1 firing, where you want to be. DON'T use the timing mark. Then drop the dist in such that the rotor points just barely to the driver's side of straight ahead. Install the plug wires in the factory locations: #1 just to the driver's side of straight ahead, #8 just to the pass side of straight ahead, #3 next, etc. all the way around.

 

Well I'm sure the intake will be partly open, but I'm not sure about the exhaust. Either it will be almost closed or just have closed. I know at some point the intake and ex valves will both be open (valve overlap, depends partly on lobe separation of cam) but I don't know if that point is when the #6 piston is at the very top of its exhaust stroke. But now you've got me wondering...

 

when #1 is at TDC of the compression stroke (firing) #6 is a TDC of the exhaust. The exhaust is just closing and the intake is just starting to open. It happens 180 (camshaft or distributor) degrees after #1 gets to this point.