chopperdave90

having some serious issues with oil pressure. took the motor back out and primed the engine with a drill. could only get 10 lbs with two different pumps.

SwampWS6

iTrader: (7)

When I primed my pump I got 70-75lbs the first time with a drill. I have a Melling HV pump too

LT1FirebirdSLP

iTrader: (2)

My HV gave me about 80 on initial start. Even with a regular volume job and cold oil, I would think you should see well above 10.

chopperdave90

It seems like I'm losing oil somewhere......I just have no idea where.

LT1FirebirdSLP

iTrader: (2)

Another thought.

I vaguely remember reading an LT1 engine rebuilding book awhile back that mentioned a ball bearing somewhere above the oil pump but below where the distributor would go if it was a conventional SBC. If it didn't get put back there during reassembly, it would result in this problem. I'll see if I can find the book and get the specifics. Maybe someone can chime in.

https://ls1tech.com/forums/lt1-lt4-m...ring-ball.html

^^^ This might be of some use.

1994Z28Lt1

iTrader: (1)

Go into more detail about how you are priming, are you using an gen 1 sbc style old distributor drive inserted into the block that retains the collar for getting oil to the top end?

Have you checked the obvious like the oil gallery plugs at the front of the engine under the timing cover?

are you using a known good mechanical gauge?

What kind of drill are you using? is it up the the task? it takes a more powerful drill than most have laying around to turn that pump with cold oil to achieve say 50 psi of pressure.

Did you yourself check clearances at assembly?

is the oil filter full?

jaycenk

iTrader: (1)

It dose need to have torque but rpms turned don't need to be high.
On a M155 Stock volume stock pressure pump with GM white spring and stock pickup I got 60 with a cordless Milwaukee on low speed torque setting after system was primed oil filled to all lifters and rockers. at higher speeds on the drill I got 65 - 68 psi.
Once I got engine running I got 60 psi cold and 35 to 40 psi at idle hot. Love that white spring.

chopperdave90

As it turns out.....my cam bearings are wiped out bad. I was using a Milwaukee electric drill with a sbc prime tool. I was curious about if using that would work because oil not flowing around the drive assembly and into the hole on the other side of it. I'm definitely gonna prime this motor when I get it back together to insure I have adequate oil pressure before putting the motor in the car this time. Lesson learned the hard way.

SS RRR

iTrader: (2)

Do you mean 10psi using a drill? If so you won't build hardly any pressure using a drill. It will not turn enough RPM to spin the pump to build pressure like you would see with a running engine.

shbox

IDK, I got plenty of pressure doing it on mine.

noice

Yea I've used a drill on every engine I can. I've even used a drill on the end of a dry sump 5 stage pump to prime an engine.

It works well, every engine I put on the dyno gets primed minutes before it is fired up for the first time.

SS RRR

iTrader: (2)

Weird. Perhaps it's just the difference in drills. I've only done this in-car and used right angle drills on "high rpm" and have had enough oil barely dribble out of the rockers and did not register hardly any pressure on the gauge, yet register normal when the engine was running.

shbox

I don't really expect much oil out the rockers, since they are notorious for getting going with oil. I used my cordless drill and a meter hooked up to the factory sensor to get a resistance reading. Then translated that reading to a pressure reading (I didn't have a mechanical gauge). I didn't write it down, but seem to remember I could get around 40# at least.

noice

If you used any kind of assembly lube then there won't be oil to the rockers for quite a while. The lube will handle the lubrication until the oil gets there. I use an old craftsman drill or a dewalt cordless. Both can easily peg the relief on the pump.