So i have a 2005 lq9 and i recently put stock sized 243s on them. Only one exhaust valve is hitting. I just put a brand new ms4 with ls7 lifters in and the cam was alighed by a professional. I cant seem to figure out what the problem is i tighten down that rocker arm and it keeps pushing the valve down no matter what the cam lope is??? need help fast

 

im having the same issue on some of my lifters as we speak... some of my lifters compress while others push the valve spring down when torque'n rocker bolts. are they new or used lifters or maybe they are new/used lifters like mine?

 

they are used but only for 1,000 miles we need help people lol

 

after playing with a few of the stuck lifters they are now starting to accept preload. my lifters were new/used 300miles i was told. I guess they were full of assembly lube or what ever the hell they were coated in when i got them

 

so it was the motor oil in the lifters ?

 

seems like it to me. i just put them on till the rocker was snug and the spring wasnt compressed at all, then i turned the crank till the spring was compressed some, i left it there for a while then took the rocker off and checked and there was some preload in the lifter...

 

would your vaulve stay stuck open?

 

yeah they would. it's taking me a while to get them to accept preload. My engine is at the bare minimum acceptable clearance for PTV so any tiny bit my valves hang open causes my valves to hit the piston.

 

damn ... that sucks

 

Verify pushrod length!

 

the push rod legth would do that to only one valve?

 

i have zero lash at 7.350,,, im installing 7.450 Push Rods. what about you LSjim?

 

i have 7.40s i only hAve a problem with the one valve wbu?

 

i was having problems with several of them... after playing with them for a while and trying to set them properly, i took all the rockers off and started over again from TDC on compression stroke set: set intake #1,3,4,5 and exhaust #1,2,7,8.... then i rotated the crank 360* and set intake #2,6,7,8 and exhaust #3,4,5, 6. after doing that once or twice they all were accepting preload and not holding the valves open

 

lol i feel slow so did that solve your problem?

 

i thought it did so i put the valve covers back on. then i tryed spinnen the crank 360* 4 or 5 times and all seemed good. i then cleaned up all my stuff, went back outside and tried to spin it around a few more times to make sure and this time it got hung up somewhere, so i turned the crank counter clockwise a tiny bit and back clockwise and it spun fine.... sooo im not sure if i fixed it but its to dark out now for anymore work today. hope its all good but i guess i will find out

 

damn aint that a bitch were both having problems... to bad it seems like no one else wants to help us lol

 

haha i know i guess know one has read the thread that has an answer... im kinda pissed that i worked on the valves all day, just to think all is good and put the covers back on just to have a hard time turning the crank... maybe it wasn't my valves hitting the pistons maybe it was just me getting tired.... i don't really understand why i am having such a problem,,, the cam is only a 233/237 with stock heads and stock thickness head gasket. when i checked my PTV with the checker springs i got .080" on the intake and .100" on the exhaust but who knows maybe i fucked that up as well... i guess i will turn it over again by hand tomorrow and see if it turns smoothly. if not i guess i will pull the rockers off and install checker springs on the number 1 cylinder and try to get my PTV accurately this time

 

damn man i am going threw the same pain at first i thought it might have been a spun bearing or rod ...

 

TTT... ok so i looked at my old LS1 lifters that i have sitting in the garage to see if i can push the plungers in by hand with a pushrod. on some of them i can push the plunger in just fine while on others the plunger wont budge. so i took one of the stuck lifters appart (removed the C clip, plunger and washer that is under the plunger). I then moved the little ball that is inside the lifter to the side while at the same time pushing down on the internal cylinder and out cam alot of oil. I then put the lifter back together and tryed to push the plunger in with a pushrod and it moved up and down perfectly. So does this mean i have to pull my heads back off, pull all the frozen lifters out, take them apart, bleed them, put them back together then re-install the lifters in the motor? Wow!!!! i was hoping that if i put some spring pressure (hang the valves) for a few days the lifters would bleed out but it doesn't seem that they are and due to this fact i am having PTV issues since i was tight already.