Another TDC Question

[jazzyjay]

WHen the cams are at Top Dead Center are all the valves for the #1 cylinder and the #4 cylinder supose to be closed or All the vaves supose to be closed? Thanks for your help in advance

 

[Bostedquest]

when the cam keys are at the top.
And when the matching timing marks line up.

 

[bullettdsm]

^^ Huh?? To both.
MB

 

[GTM]

WHen the cams are at Top Dead Center are all the valves for the #1 cylinder and the #4 cylinder supose to be closed or All the vaves supose to be closed? Thanks for your help in advance

NO!!!
TDC, #1 ignition. Exhaust cam will be first to open then followed by the intake. #4 cam lobes will be on the rock where the exhaust is just about closed and the intake has just started to open (valve overlap). ALWAYS on a 4 cylr inline engine. 1,3,4,2, outboard pistons up inboard down. #3 intake will almost be closed or closed for it will come up to ignition next in the sequence. Always, always, always.

Was there a reason for the question?

Cheers,
GTM

 

[Bostedquest]

^^ Huh?? To both.
MB

The cam bolts have woodruf (spl?) keys in them.
The cam sprockets have a notch every 90 degrees. But they are in sets. A peak mark matches the valley mark in the other sproket.

So when you have the keys in the cam sprokets facing up or 12'o'clock, they are at -0- degree's, igition cycle.

 

[jazzyjay]

NO!!!
TDC, #1 ignition. Exhaust cam will be first to open then followed by the intake. #4 cam lobes will be on the rock where the exhaust is just about closed and the intake has just started to open (valve overlap). ALWAYS on a 4 cylr inline engine. 1,3,4,2, outboard pistons up inboard down. #3 intake will almost be closed or closed for it will come up to ignition next in the sequence. Always, always, always.

Was there a reason for the question?

Cheers,
GTM

The reason I ask is That I noticed that even though The # 1 and # 4 where up the #4 all the valves where not closed. So only the #1 cyl all the vaves are closed

 

[BUCK]

^ CORRECT ^ #1 IgnitionTDC - when the Cam Keys are at the top & when the Crank Timing Marks line up.

 

[Defiant]

The cam bolts have woodruf (spl?) keys in them.

Well, they have locating dowels, but carry on.

 

[GTM]

Well, they have locating dowels, but carry on.

Somebody's been reading ahead... what, isn't this the Chevy class.