I give up...I really do! This is my fifth rebuild and I've never
come across this one.

1980 Z28, 350 CID carb.

Before starting my car, I ALWAYS pressurize the motor with oil by
disconnecting the ignition and cranking.

Normally, the pressure will stabilize within 2-3 cycles of ten second
cranks. In the past I have done this on rebuilds and the needle jumped
to 40 PSI.

I've done at least six at 10 second cycles and the gauge reads zero.

- The oil pan is full, the dipstick reads full.

- The oil gauge is not broken, I even tried another unit.

- I can see the oil creeping up the line as I crank, but it stops suddenly.

- I removed both valve covers and no oil seems to be making it's way into
the valve train.

- I have also reseated the distributor and hand primed the oil pump using
a slotted shaft from an old distributor. There is load as I turn and I
can also observe the capillary action in the oil line.


I have assembly lube on the cam, crank and main bearings. The lifters and
rods also have assembly lube.

After this long winded story, my question is:

On a BONE DRY motor, how long should it take to pressurize the motor?
Keep in mind the oil filter is topped up, but the lifters, bearings are
fresh.

My next step is to attach a drill to the shaft and prime the pump and motor.

Is my mechanical pumped screwed, or am I not waiting long enough?

Thanks for the sanity check.

 

I use a priming tool and can feel it come under load within a few seconds. And when I say load, I mean it. A 1/2" drill will struggle to turn the shaft. Priming tool has the collar necessary to seal to the lifter passages. Sounds like yours doesn't, so you might not be able to tell if there is an internal leak, like from a plug that got left off or an internal clearance being wrong, or bypass on oil pump not fully seated. Buy borrow or rent a priming tool and see how much load is present.

 

Did you soak the lifters in oil? If not you can expect to prime it for a few minutes before you get any oil up top. If you are unsure if the lifters are pumped up or not give the pushrods a push on top. you should not be able to push them in. Im assuming they are hydraulic lifters or else you REALLY wont be able to push them in . I think you are just quitting too early. Ive had drills smoking hot by the time oil makes it up top. If you cannot get oil there at all make sure your pan/pickup work together. BTW to me the whole point of priming the engine is to get oil in the bearings etc BEFORE rotating the engine. I honestly dont see much point in cranking it with the starter until it primes. Just my views though, they arent ALWAYS right .
CoryM

 

Thanks guys.

What I mean buy "cranking to prime" is that I always turn the
engine over and get pressure before I give it a shot of fuel.

It's a little safer in my eyes to get the pressure high at cranking
RPM's rather than idle RPM's.

Thanks again for the input, I'll be hooking up my drill momentarily!

 

When you say you crank the engine a couple time without fuel. Are you spinning the entire assembly with the starter? If so, and no oil is getting around, you could be damaging some stuff. This is why you should use the priming tool, I got one that pressurizes the lifter valley as well, for about $23, and you use a drill. Let us know what happened!

BamaZ28