johnny89345

iTrader: (1)

I had a ls7 lifter fail wipe out my ms4 in my texas speed 408 so I upgraded to lunati 72532 link bar lifters and a much higher duration eps cam 244/256. I also replaced the oil pump and valve springs. My tuner measured the pushrods Since I was unsure about preload and the proper length I should order with a digital calipers so I ordered 7.425 3/8 lunatis. Now I tried starting it for the first time last night and it cranks slow and sounds like a light pop out the intake. Ive done numerous cam swaps on lsx motors so im confident I didnt mess up the timing but what else would you guys suggest I look at? I feel like its either the lifters punped up all the way causing the valves to stay open or possibly too long of pushrods, please lemme know what you think!

1970camaroRS

iTrader: (8)

If the valves stayed open, it would crank faster because of no compression...but you would probably notice the valves getting bent. Sounds like the ignition and/or cam timing is FUBAR.

RockinWs6

The slow cranking kinda worries me because usually they crank slow after a cam swap if the valve train is binding some place. Did you check for coil bind? Maybe pop off a valve cover and look if they are binding or for bend push rods. I wouldn't crank it any more until you investigate thoroughly.
If it checks out Pull a few plugs and check compression, sounds like the valves are staying open OR the cam was ground wrong which is unlikely

johnny89345

iTrader: (1)

Problem solved. Im 100% retarded, when I installed the pushrods I just dropped them in not seating on the lifter where they shouod be so a few valves were slightly held open

MuhThugga

Yeah, you need to be sure the pushrod is seated on the lifter cup with the linkbar lifters. There isn't a tray that will guide the pushrod to where it needs to be anymore.

RockinWs6

Lucky you, bet yer doina happy dance now. Post up a running video if you can.

vettenuts

iTrader: (4)

Don't want to throw cold water, but the cranking slow and your explanation of the problem and the valves being held open with that large of a duration might have resulted in bent valves. You might want to check this before going too much further.