No compression after valve stem seal replacement

[Bigred3plus3]

Yesterday I put new valve stem seal on my LS swapped crewcab. I Aired up each cylinder pulled the valve spring off swapped the seals then put everything back together starting with the aluminum bar the rockers ride on then each rocker. Rolled the motor over so each lifter was at its base circle then tightened and torqued each rocker. With all that done I have to compression. I double checked everything and I'm at a loss for words. Has any one seen this? Oh and its on every cylinder not just one. WHAT THE HECK IS GOING ON! lol

 

[DoubleDingo]

I'm no LS expert, but I suspect it is the torquing of the rockers that did it. If a rocker is too tight, the pushrod is holding the valve open. Since you did all of them like that, they are all open. Hopefully you didn't bend the pushrods. I have a feeling you just made a lot of extra work for yourself. I hope I am wrong. Some LS people will will chime in soon enough, maybe they'll have better news than I do.

 

[Bigred3plus3]

Yea not being familiar with the LS the LS rockers don't have lash adjustment like a sbc does you torque rockers down to 22ft lbs. Push rods are not bent ive already pulled them out and checked.

 

[DoubleDingo]

That's good they're not bent. Still sounds like the valves are not closing.

 

[Bextreme04]

most new chevy engines are non-adjustable valvetrain. My L29 454 and the new LS motors are like that. You just install the rockers and torque the nuts down. Its suspicious that EVERY cylinder has lost compression after this. What else did you touch or mess with while you were doing this?

 

[DoubleDingo]

Did you reinstall the spark plugs?

 

[Bigred3plus3]

Did you reinstall the spark plugs?

Wow come on guy haha yes I did. I even put my compression tester in each hole. But I figured it out after talking to someone very knowledgeable. Shes up and running now. It was a lifter issue. The plungers in the lifts rose to the top of the lifter when I relieved the pressure from the rockers and they must have been some varnish that it got stuck in. I let it sit over night then heated the motor up with my shop heater and regained compression in 5 cylinders so decided to try and start it and it fire off then ran rough for about 45 seconds then started clearing up. Now she runs nice and smooth. Zero issues now.

 

[Ricko1966]

Loosen the rockers real loose but not off on 4 cylinders try to start it on 4 then tighten the rockers up the lifters biked off and won't pump back up.

 

[DoubleDingo]

Wow come on guy haha yes I did. I even put my compression tester in each hole. But I figured it out after talking to someone very knowledgeable. Shes up and running now. It was a lifter issue. The plungers in the lifts rose to the top of the lifter when I relieved the pressure from the rockers and they must have been some varnish that it got stuck in. I let it sit over night then heated the motor up with my shop heater and regained compression in 5 cylinders so decided to try and start it and it fire off then ran rough for about 45 seconds then started clearing up. Now she runs nice and smooth. Zero issues now.

Sometimes it's the simple things we overlook. It was worth an ask, so I asked.

Glad you figured it out and got it back up and running.

 

[Bigred3plus3]

Sometimes it's the simple things we overlook. It was worth an ask, so I asked.

Glad you figured it out and got it back up and running.

Hahaha no worries. Yeah im glad it was something simple but also complicated.