I have a 91 Camaro with the LO3.
I'm doing some problem diagnosing and I am wondering are the lifters supposed to be that free to move in their bores cause when I rebuilt the engine I pratically had to pry them out.

Also does the oil pump make a funny grinding sound when you spin it when its out of the car.

Would a HV oil pump damage the lifters.

Why when I use an oil priming tool to run the oil pump does only one head have oil flowing over it an the other dry as a bone.

Is there anyway to test if the lifters are working properly. I tried putting a vacuum pump on the top and tried to pull the oil through one of them but it didn't seem to work right.

What is the valve spring rate for the valve srings on my LO3, they are stock heads.

 

The lifters should come right out of their bores. When they don't, it's usually built-up varnish from not-frequent-enough oil changes, or using really cheap oil.

Did you clean out all the oil passages when you rebuilt the engine? This is best done by first having a machine shop run the block through their cleaner ("tanking", it's often called), then using soapy water and small bristle "bore brushes", like coffee pot cleaners, to clean out all the oil passages. Rinse with clear water, blow out all the passages with compressed air, spray down with rust preventive until you can get it together and oiled.

It isn't easy to block off one bank of lifters from getting oil flow, but I suppose it's possible.

Oil pumps aren't silky-smooth, but it shouldn't make a grinding noise. I've only put an engine back together with an old pump once - the HV replacement I had didn't clear the oil pan baffle. Rather than fool with the baffle, I put the old pump back in. 300 miles later, the first time I got on it at all, I lost 10 psi of oil pressure and had a low-end knock. All of those new bearings were wiped out.

Soak the lifters in clean fresh oil for several days, changing the oil every day. That usually helps refresh them (we are talking roller lifters, right?).

 

Yeah they are roller lifters and the engine block was cleaned by the machine shop.

I've had trouble with the oil pressure since I repaired the oil leak in the back of the manifold about 2 weeks ago. Its really confusing to me how an entire side gets cut off. I'm gonna run some pipe cleaners in there and once I get the new oil pan and stock oil pump back on, I'm gonna pump oil through the engine without the lifters to see if the problem is still there. To make sure the oil is alteast going to that side of the engine.

That really sucks about loosing the new engine, I'm hoping someting like that doesn't happen to me.

 

Wonder if a galley plug popped out on you, one behind the timing gear.