Timing before checking valves?
- Thread starter Kent
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If you are checking, and adjusting with the motor off, all you need is the TDC line on the timing mark. Make sure your rotor is pointing toward the #1 wire for the first check, otherwise you will be 180* off. TDC line doesn't care where your timing is adjusted.
- Thread starter
- #5
Ok thanks. I didn't think the valve clearances were affected by timing. I am under the impression the motor should be warmed up when checking them correct? They can be checked with it running correct?
Warm definately. Running yes, though I have only checked with the motor off, and in position by the TDC mark. There is good information in the FAQ on valve adjustment.
Two are not related, valve clearance has to do with the rotation of the engine, so you will need to rotate the engine to adjust the valve clearance. Timing is the ignition point in relation to the cylinder movement, so turning the distributor will have no impact on when the valves open or close, only when the spark will happen. So warm the engine and adjust those valves.
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Yes, at operating temperature.
No, solid lifters are checked with engine off and valves closed.
Yes, at operating temperature.
No, solid lifters are checked with engine off and valves closed.
If you have an aftermarket cam shaft, such as the MAF RV Cam ,do set the gap the same as Stock Specs or something different?
- Joined
- Sep 26, 2003
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- 11,199
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- Lancaster, Ohio, USA
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- www.tlcperformance.com
The cam grinder will print that on the cam tag, along w/ degree info.
valvetrain vs ignition timing
the valvetrain timing relates to timing the lift (or lack of) of the valves to the crank position and therefore piston position
The ignition timing times the firing of the spark relative to the piston position
so the valvetrain is timed to the crank and so is the ignition but for different reasons and physically changing one will not change the other
The correct clearance or lash of a solid lifter allows the valve to close all the way and open as far as it should. When the lifter has gap the spring is holding the valves closed so you can have compression
If you are thinking of changing the cam it should be one with a solid lifter grind ---the ramp up rate on the lobes are not as abrupt as they are on cams designed for hydro lifters
Unless that is if someone makes hyd lifters for a 40 and a hyd cam to suit also--have not even looked at that so I cant say
I would miss the tickety tick
the valvetrain timing relates to timing the lift (or lack of) of the valves to the crank position and therefore piston position
The ignition timing times the firing of the spark relative to the piston position
so the valvetrain is timed to the crank and so is the ignition but for different reasons and physically changing one will not change the other
The correct clearance or lash of a solid lifter allows the valve to close all the way and open as far as it should. When the lifter has gap the spring is holding the valves closed so you can have compression
If you are thinking of changing the cam it should be one with a solid lifter grind ---the ramp up rate on the lobes are not as abrupt as they are on cams designed for hydro lifters
Unless that is if someone makes hyd lifters for a 40 and a hyd cam to suit also--have not even looked at that so I cant say
I would miss the tickety tick