Knock Sensor picking up headers?

[m j]

with you on this one Tim
no correlation between cam degreeing and ignition firing unless your trigger is machined into the cam like a flying magnet
even then you would be foolish to make the pickup non-adjustable

as for knock sensors, throw it out, GM only phenom IIRC

 

[1-ton]

Re: Knock Sensor picking up headers? *DELETED*

Post deleted by 1-ton

 

[m j]

no
I do not get the idea
I use a piston stop to determine TDC
the cam does not need to be installed in the engine
in fact to degree the cam you also use a piston stop
degree the cam anyway you want
it still doesnt affect ignotion firing in relation to the crankshaft timing mark

[ QUOTE ]
that both the intake and exhaust valves are 100% closed

[/ QUOTE ]

no idea why you add this bit

I will reread your post to see if there was any relevant info that I may have overlooked

 

[m j]

it looks as though when the rest of the world gives a timing spec in relation to crankshaft degrees you are choosing to give it in camshaft degrees

 

[84_Chevy_K10]

[ QUOTE ]
Timing light accuracy depends on the fact that when the number #1 cylinder is on the compression stroke, and the Harmonic Damper timing mark is lined up exactly on the "zero" mark on the timing tab, that both the intake and exhaust valves are 100% closed. With a GM factory camshaft, which is indexed to the crankshaft when machined, this is true. But, with an aftermarket camshaft this is not true.

Say that with an aftermarket camshaft, when the Harmonic Damper timing mark is lined up with the timing tab zero mark on the #1 cylider compression stroke, that the intake valve is still slightly open, instead of both valves being 100% closed like on a factory camshaft. Now say that, In order to have both valves 100% closed, you have to roll the Harmonic Damper timing mark back to "negative four degrees" (-4) on the timing tab. This (-4) degrees now becomes your true "zero" mark for a timing light. Now when you advance the timing 8 degrees forward of the (-4) degree timing mark (which would be +4 degrees), you are truly firing the spark plug at +8 degrees before both valves are 100% closed. Do you get the idea?

[/ QUOTE ]

I'm calling BS once again.

Valve opening and closing events have absolutely no relation to ignition timing.

Do you even know what ignition timing is? Can you explain that to us?

Normally I give damn near anyone the benefit of the doubt but you're beyond off the wall with the comments in this thread. I've never heard such nonsense in my life.

 

[POWERMAD]

[ QUOTE ]
it looks as though when the rest of the world gives a timing spec in relation to crankshaft degrees you are choosing to give it in camshaft degrees



[/ QUOTE ]
Not to jump in and gang up on Chris but that is the way I am seeing it.
Advancing or retarding the cam moves the powerband up or down.
That still does not affect ignition timing.
The plug still has to fire when the piston is near or at TDC depending on the engine.
But Chris does make a valid point in using a vaccume gage in establishing ignition timing with an aftermarket cam.
No matter if you choose to set em up straight up and down or play around with the cam it is a good idea to use a vaccume gage to get optimum performance out of it.
With the damper properly degreed you can then check to see where it is at.
But I do think that something would have to be seriously flawed if a valve was slightly open when the plug fires.
If that was the case then the cam would have to be realy out of whack to have a valve open when the piston is at around 8* BTDC.
Both valves should be closed when the piston is at the bottom of the intake stroke and starting its way back up on the compression stroke let alone at the top of the compression stroke.
/forums/images/graemlins/thinking.gif

 

[1-ton]

Re: Knock Sensor picking up headers? *DELETED*

Post deleted by 1-ton

 

[m j]

ok what is it you are trying to argue?

that the cam plays a role in whether a timing light will give accurate representation of when, in crankshaft degrees, the ignition fires

or

that the spec may or may not be the correct time to fire the ignition

on the former I disagree
on the later I agree

in my engines the valves better be closed TDC on the compression stroke

 

[84_Chevy_K10]

[ QUOTE ]
in my engines the valves better be closed TDC on the compression stroke

[/ QUOTE ]

I couldn't agree more. If your valves are open during the compression stroke you're sure as hell not going to have much compression.