oil pressure?

**spider** · 05-18-2008, 09:57 AM

new guy here with a problem with getting oil pressure on 2002 LS1
installen in my 55 chevy. changed oil pans and pickup tube on the 40,000 mile engine
purchased from salvage yard. Should it have oil pressure using the starter only? I took
the plugs out and it spins fast but no pressure on the dakota digital.??

**bills98ta** · 05-18-2008, 06:40 PM

The pickup tube had the O-Ring ??? I noticed my new build didn't build pressure until I started it up, then it had 65lb quick...

**spider** · 05-18-2008, 06:51 PM

It had the O ring on it. It must not be priming as when I crank the engine over it doesn't put any oil out even when the filter is off. Wish I knew how to prime it. Put oil in above the oil filter but it still would not pump it back to me. Even put a vacuum on the hole and cranked it over at the same time but no oil. Will try the oil sending unit hole next??? sure do hate to pull the pan again. Thanks

**spider** · 05-18-2008, 06:53 PM

It had the O ring on it. It must not be priming as when I crank the engine over it doesn't put any oil out even when the filter is off. Wish I knew how to prime it. Put oil in above the oil filter but it still would not pump it back to me. Even put a vacuum on the hole and cranked it over at the same time but no oil. Will try the oil sending unit hole next??? sure do hate to pull the pan again. Thanks

**bills98ta** · 05-18-2008, 07:20 PM

If it's ready to fire up, I'd start it and see. Should only be seconds for it to prime. Can't really prime that oil pump...

**spider** · 05-19-2008, 04:11 AM

May just do that, thanks

**Firebirdjones** · 05-19-2008, 05:34 AM

The only way to prime the engine before start up is to use a pressurized tank with 5 quarts of oil....and shoot that into the engine under air pressure before startup,,,thats how GM did it.

**spider** · 05-19-2008, 06:14 PM

Where did GM attach the tube or whatever they used to shoot the oil into the engine?

**Mr. Luos** · 05-19-2008, 06:51 PM

Originally Posted by spider

Where did GM attach the tube or whatever they used to shoot the oil into the engine?

Please explain this a little better for me.

It took 10-12 seconds of cranking my 402 (no spark/fuel) before my gauge showed any pressure.

**Firebirdjones** · 05-20-2008, 02:11 AM

I will check to be sure but my guess would be the oil pressure sending unit before it was installed. Keep in mind I beleive GM did this process before the engine/K-member was lifted into the car.

Another way for the backyard mechanic to do it while engine is in the car,,,and I am just thinking outloud here,,,,would be to drill/tap the oil galley access just above the oil filter?????

You could thread the line into there, pump the oil in via air pressure to prime the engine,,,then plug it when not in use. Just a thought.

As Luos mentioned, cranking the engine may get you there, but with the gear reduction starter on these LS motors they turn rather slow. Even with the spark plugs out they don't turn that fast.
You may get some oil pressure this way, keep in mind you are moving all the internal parts while you're waiting for oil pressure though.....But,,,,,since you are not working on a brand new engine,,,,and it already has 40,000 miles on it,,,it may not be as much of an issue.

Just to add, when I prime motors the old fashion way,,,,through a distributor hole with a primer and drill,,,,,,this is not something that is done in 1 minute. With the valve covers removed it takes several minutes, sometimes more,,,,until you see oil coming up through all the rocker arms. Sometimes it requires rotating the motor around and prime the oil some more before all the rockers are soaked in oil.

To prime an engine this way by simply cranking would take a long time,,,and would run the battery down. Not to mention starters are not designed to be cranked for long periods of time either. Simply cranking a fresh engine that is dry up top until you see "oil pressure" on the gauge more than likely does not have all the lifters pumped up nor have oil up to the rocker arms. Kind of a scary thought on a fresh motor if you ask me.