Question on checking PTV clearance
08-04-2010, 09:21 AM
#1
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Question on checking PTV clearance When checking PTV on a motor with hydraulic lifters, would you still require a solid lifter when using checking springs?
The reason I ask is that the replacement lifters I'm using (LS7 style) are different than what originally came in the LQ4. As such, I can't convert the stockers to solid for a proper check.
Otherwise, is there a non-destructive method to convert the newer style lifters to solid temporarily for checking PTV?
The reason I ask is that the replacement lifters I'm using (LS7 style) are different than what originally came in the LQ4. As such, I can't convert the stockers to solid for a proper check.
Otherwise, is there a non-destructive method to convert the newer style lifters to solid temporarily for checking PTV?
08-04-2010, 11:41 PM
#3
if your using a checking spring you should be fine with the hydraulic lifter. its when u use your actual springs that you NEED to use a solid lifter. if you want to be on the safe side you can add a couple thousandths to your ptv reading and assume the lifter bled a bit.
08-05-2010, 05:12 AM
#4
You need an adjustable pushrod and check springs. Set the pushrod length so you have zero lash with the lifter on the base circle. Use the dial indicator method (not clay) and at each step make sure you aren't compressing the lifter plunger. I would gently depress the rocker at each crankshaft increment to ensure the pushrod doesn't get pushed up. In other words before pressing the valve to contact the piston, just slightly depress the valve with the rocker and see if the pushrod becomes loose. If it does, then the lifter plunger should still be at the top as it would be with a solid lifter. If the pushrod comes up when the rocker moves, then the spring in the lifter has compressed and is skewing your results.
The other option is to make a solid lifter from the old ones and lengthen the adjustable pushrod to zero lash. The perform the dial indicator method normally.
The other option is to make a solid lifter from the old ones and lengthen the adjustable pushrod to zero lash. The perform the dial indicator method normally.
08-05-2010, 04:17 PM
#7
You need an adjustable pushrod and check springs. Set the pushrod length so you have zero lash with the lifter on the base circle. Use the dial indicator method (not clay) and at each step make sure you aren't compressing the lifter plunger. I would gently depress the rocker at each crankshaft increment to ensure the pushrod doesn't get pushed up. In other words before pressing the valve to contact the piston, just slightly depress the valve with the rocker and see if the pushrod becomes loose. If it does, then the lifter plunger should still be at the top as it would be with a solid lifter. If the pushrod comes up when the rocker moves, then the spring in the lifter has compressed and is skewing your results.
The other option is to make a solid lifter from the old ones and lengthen the adjustable pushrod to zero lash. The perform the dial indicator method normally.
The other option is to make a solid lifter from the old ones and lengthen the adjustable pushrod to zero lash. The perform the dial indicator method normally.
