Valvetrain/Ptv getting hung up
Valvetrain/Ptv getting hung up Been doing my cam/lifter swap for awhile now and nothing but problems. With a solid lifter and checker springs, I put in a 7.400 pushrod, set to zero lash, turned motor over and I was given clearance on both intake/exhaust. Being happy with this, I went to bolt the head down with factory springs, but still solid lifters, 7.400 pushrod, I tightened down rocker to 22ft.lb. awhile I was torquing down, the spring compressed, a lot before the rocker reached 22ft.lb. I went to turn the motor over it just stops (I'm assuming piston to valve contact is stopping it). What is causing this?
Why are my springs collapsing when tightening rockers?
Car/parts: 98 Camaro
Tsp 233/239 cam
7.400 pushrods (have not measured to check of these are what ill be using, I was told to check for length after heads are installed by tsp??)
Stock 806 ls1 heads, decked 5 thousands just to clean gasket off
New springs up to .650 lift if I remember correctly (purchased with cam package from tsp, was originally going to run ms4)
Why are my springs collapsing when tightening rockers?
Car/parts: 98 Camaro
Tsp 233/239 cam
7.400 pushrods (have not measured to check of these are what ill be using, I was told to check for length after heads are installed by tsp??)
Stock 806 ls1 heads, decked 5 thousands just to clean gasket off
New springs up to .650 lift if I remember correctly (purchased with cam package from tsp, was originally going to run ms4)
You need to use an adjustable pushrod. Since the 7.400" pushrod is deigned to give you preload in the lifter, it is instead compressing the spring since you have a solid lifter. This is opening the valve more, causing your PTV issue.
You need to put the hydraulics lifters in if you already checked ptv clearance. When you tighten the rockers with the hydraulics it will preload the lifter and not hold the spring open. The valve may open when you first tighten it down but the lifter will bleed off and the valve will close.
Registered User
Joined: Jun 2013
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You need to put the hydraulics lifters in if you already checked ptv clearance. When you tighten the rockers with the hydraulics it will preload the lifter and not hold the spring open. The valve may open when you first tighten it down but the lifter will bleed off and the valve will close.
Sorry, I forgot to mention that. I used an adjustable pushrod when checking ptv, I didn't use the 7.400 like previously stated. So what I wanted to do was turn the motor over without the zero lash deal, so it was the real world situation when I go to fire it up.
So I stuck 7.400 pushrod, used my new springs, and torqued the rockers to 22ft.lb, and it collapsed the spring a bunch, then when I turned the motor over, it just stops.
Since I already checked the ptv, and I'm happy with my clearances, should I now stick my new ls7 lifters in there, slide in a 7.400 pushrod, tighten to 22ft.lb, then turn motor over to make sure everything is ok? Will this be accurate since once the motor is turned on, the lifter is pumped up with oil, making it act as a solid? or am I not understanding this correctly?
So I stuck 7.400 pushrod, used my new springs, and torqued the rockers to 22ft.lb, and it collapsed the spring a bunch, then when I turned the motor over, it just stops.
Since I already checked the ptv, and I'm happy with my clearances, should I now stick my new ls7 lifters in there, slide in a 7.400 pushrod, tighten to 22ft.lb, then turn motor over to make sure everything is ok? Will this be accurate since once the motor is turned on, the lifter is pumped up with oil, making it act as a solid? or am I not understanding this correctly?
Registered User
Joined: Jun 2013
Posts: 23
Likes: 0
Sorry, I forgot to mention that. I used an adjustable pushrod when checking ptv, I didn't use the 7.400 like previously stated. So what I wanted to do was turn the motor over without the zero lash deal, so it was the real world situation when I go to fire it up.
So I stuck 7.400 pushrod, used my new springs, and torqued the rockers to 22ft.lb, and it collapsed the spring a bunch, then when I turned the motor over, it just stops.
Since I already checked the ptv, and I'm happy with my clearances, should I now stick my new ls7 lifters in there, slide in a 7.400 pushrod, tighten to 22ft.lb, then turn motor over to make sure everything is ok? Will this be accurate since once the motor is turned on, the lifter is pumped up with oil, making it act as a solid? or am I not understanding this correctly?
So I stuck 7.400 pushrod, used my new springs, and torqued the rockers to 22ft.lb, and it collapsed the spring a bunch, then when I turned the motor over, it just stops.
Since I already checked the ptv, and I'm happy with my clearances, should I now stick my new ls7 lifters in there, slide in a 7.400 pushrod, tighten to 22ft.lb, then turn motor over to make sure everything is ok? Will this be accurate since once the motor is turned on, the lifter is pumped up with oil, making it act as a solid? or am I not understanding this correctly?
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Sorry, I forgot to mention that. I used an adjustable pushrod when checking ptv, I didn't use the 7.400 like previously stated. So what I wanted to do was turn the motor over without the zero lash deal, so it was the real world situation when I go to fire it up.
So I stuck 7.400 pushrod, used my new springs, and torqued the rockers to 22ft.lb, and it collapsed the spring a bunch, then when I turned the motor over, it just stops.
Since I already checked the ptv, and I'm happy with my clearances, should I now stick my new ls7 lifters in there, slide in a 7.400 pushrod, tighten to 22ft.lb, then turn motor over to make sure everything is ok? Will this be accurate since once the motor is turned on, the lifter is pumped up with oil, making it act as a solid? or am I not understanding this correctly?
So I stuck 7.400 pushrod, used my new springs, and torqued the rockers to 22ft.lb, and it collapsed the spring a bunch, then when I turned the motor over, it just stops.
Since I already checked the ptv, and I'm happy with my clearances, should I now stick my new ls7 lifters in there, slide in a 7.400 pushrod, tighten to 22ft.lb, then turn motor over to make sure everything is ok? Will this be accurate since once the motor is turned on, the lifter is pumped up with oil, making it act as a solid? or am I not understanding this correctly?
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Brett Foote OK. The thing im not getting is when checking ptv, you use a solid lifter to make sure there is clearance because otherwise the lifter collapses from the pressure. When I start the motor, the lifters are going to pump up with oil, wont this make the lifter act as a solid lifter? Granted I have very little knowledge of valvetrain so I may be totally wrong.
With that being said, right now, when I turn the motor over with real pushrods, springs, but still a solid lifter, why does my motor seize, timing chain gets super tight, and I can no longer turn the motor over? I just re-did this text with clay just to see if piston and valve are hitting super hard causing it to stop, but they are NOT. Whats causing this?
With that being said, right now, when I turn the motor over with real pushrods, springs, but still a solid lifter, why does my motor seize, timing chain gets super tight, and I can no longer turn the motor over? I just re-did this text with clay just to see if piston and valve are hitting super hard causing it to stop, but they are NOT. Whats causing this?
LOL You need a push-rod length checker to find out what length push-rods you will need. You need to measure ptv clearance after finding the proper size push-rods you will need and can do this from a few methods. You can use the clay method which involves putty a piece of clay down on top of the piston and measuring the clay after you do an imprint of it or you can use a dial indicator that sits on top of the spring retainer to measure movement but you need to find the total amount of movement from piston to valve contact first as a baseline then you can subtract from that to get your PTV clearance.
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Joined: Jun 2011
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From: Katy, TX
Quit giving the guy ****.
OP, you only checked PTV the first time around. And you did it correctly.
You didn't establish the correct pushrod length.
That needs to be done with the hyd lifter you plan to use. Same process. Find 0 lash with the lifter on the base circle, measure the checking pushrod, add the amount of preload you want, say .080" and you now know the correct length and can order.
The 22ft lbs is only the torque spec for the bolt. Nothing else.
This simple direct measurement eliminates counting turns and confusion.
It does require a pair of 8" calipers avail from Horrible Fright for about $20.
Ron
OP, you only checked PTV the first time around. And you did it correctly.
You didn't establish the correct pushrod length.
That needs to be done with the hyd lifter you plan to use. Same process. Find 0 lash with the lifter on the base circle, measure the checking pushrod, add the amount of preload you want, say .080" and you now know the correct length and can order.
The 22ft lbs is only the torque spec for the bolt. Nothing else.
This simple direct measurement eliminates counting turns and confusion.
It does require a pair of 8" calipers avail from Horrible Fright for about $20.
Ron
pushrod checker i bought one of these..pretty slick and you don't need a large caliper..i just need another one so i can check the exhaust and intake at the same time when checking ptv clearance...http://www.jegs.com/i/Comp+Cams/249/7702-1/10002/-1 hth Bob
Quit giving the guy ****.
OP, you only checked PTV the first time around. And you did it correctly.
You didn't establish the correct pushrod length.
That needs to be done with the hyd lifter you plan to use. Same process. Find 0 lash with the lifter on the base circle, measure the checking pushrod, add the amount of preload you want, say .080" and you now know the correct length and can order.
The 22ft lbs is only the torque spec for the bolt. Nothing else.
This simple direct measurement eliminates counting turns and confusion.
It does require a pair of 8" calipers avail from Horrible Fright for about $20.
Ron
OP, you only checked PTV the first time around. And you did it correctly.
You didn't establish the correct pushrod length.
That needs to be done with the hyd lifter you plan to use. Same process. Find 0 lash with the lifter on the base circle, measure the checking pushrod, add the amount of preload you want, say .080" and you now know the correct length and can order.
The 22ft lbs is only the torque spec for the bolt. Nothing else.
This simple direct measurement eliminates counting turns and confusion.
It does require a pair of 8" calipers avail from Horrible Fright for about $20.
Ron