I went to check pushrod length tonight, and found a lifter to be pretty soft. With the pushrod in place, i can push the pushrod down into the lifter with a bit of effort.

Im pretty sure this is not right, but do i have a failing lifter? They were brand new LS7 lifters, and they only have 300 miles on them. I didnt notice any abnormal noises prior to pulling the rockers, but now, i think im more aware of it, and am getting some tapping.

Im supposed to be going to the tuner tomaro, but Im not sure thats going to happen now.

 

I had a buddy of mine put together a small ford, ran it to break it in, pulled the covers off and noticed some blueing from heat. Not saying this is your problem or not, but he ended up pulling his lifter to check it out and noticed there were no oiling holes drilled into the lifter, hence the heat and it didn't compress. Now I check the lifters a little more closely whenever I put together a motor. Might be something to check out.

 

If the lifter piston was compressed at all, it pushed out some oil. If there was no oil to re-supply the lifter, you sucked in air, now it's "spongy". It should pump-up once it gets oil pressure. With that said, it is possible to have a leaky lifter that won't pump-up so keep an eye on it. On 1st start, that lifter will be a little noisy but should quiet right up.

 

To add to this, I recently installed a used shortblock and a freshly rebuilt shortblock in my camaro. Both times, it took about 3-4 minutes before the valve train quieted up and the lifters pumped up all the way. Took about 30 seconds before they stopped being really loud.

I put in used LS7 lifters soaked in oil, couldn't compress the lifter by hand.