Low Oil Pressure

Took the Scamp for a drive and the oil pressure was dropping to zero on the gauge at idle, rpms up it increases but still low. Changed to different headers and wondering if the header too close to the oil filter could create such a drastic change. The Hedmans are a bit closer than the TTI's were to the filter, no other changes except different mufflers. Motor was only running for about 10 minutes max, oil level full and about 85* outside
Thoughts?

First step try a new gage then maybe screw on a new filter so you can cut that one apart and inspect for anything that shouldn’t be there.

You probably didn't run it long enough to get the oil temps up above 220 F so I don't think the oil temps. are a player now

Update, tried new gauge no pressure, took filter off and cranked the motor over nothing from the filter as far as pressure
What to check next?
1. oil drive shaft stripped?
2, drop the pan and new pump?
any way to bench test a pump? Any else you can think of Im all ears
Thanks

Common on chevies but rare on mopars but you may have to drop the pan to check the oil pickup. How did the oil filter look as far as contamination. Good, bad. If bad it has to come apart anyway. If it’s a pump at least they are pretty cheap. If it’s bearings, not so much.

Sounds like you should pull the distributor and try a priming tool and a drill

Filter looked good so I put it back on, pulled distr. and primed with a drill, had to rev drill pretty good but have pressure at gauge and to the rockers. If I remember correctly I have a 10-30 weight oil where I usually run the 20-50 Valvoline race oil (they were out)

can the change in viscosity make that big of a difference?
or possibly oil pump getting weak?

Just curious but what kind of filter. And yes viscosity can affect it but also remember the drill rpm doesn’t duplicate engine rpm. Years ago I ran 40 weight, then 30, then 10-40, now 10-30. With the RacePak I can closely watch what is going on during a pass and in the pits.

I run a Napa Gold and always have, going to put the Valvoline back in and change filter one at a time to see whats up. Thanks for the tips

He already took the filter off the block and cranked it to find no oil coming out of block. What does the filter have to do with anything? Waste of time and money to try a different filter at this point.

Read his post above. He has oil pressure now but it’s not as high

No problem I hope all turns out well for you

Going from 20-50 to 10-30 will make a difference. But not a 30-40 PSI difference. I use a 1/2 drill and 2 hands to spin the pump with authority while priming. If you're spinning the pump easily with a 3/8, something's fishy. Wide open with an 800 RPM 1/2 drill should get 60-70 PSI and running the drill slow maybe 30. If not, I would try another filter for the heck of it before looking deeper.

how much pressure?

went back to original gauge and primed with a 3/8 drill 68 psi,
so something made the gauge drop to zero, the hunt is on.
will let you know what I find

Maybe some tiny bit of debris in the bypass valve in the pump making it stick open when it acted up hot?
I've seen that more than once in BB, they are a lot easier to check also
Good luck, you will find it

If you tried this the first time right after changing the oil sometimes it takes a little longer to pick up pressure

Finally had a chance to get out to the shop (house remodel)
pulled the filter and cut it open, no metal
Drained the oil and going to let it set overnight covered
so I can inspect tomorrow, looked pretty good so far
think I will try another filter and the 20-50 Valvoline
oil I normally run and see what happens. I will update my findings
and thanks for the advice

Sounds like you left a plug out somewhere.

Kink in oil pressure line? While doing the headers? Copper or nylon easy to damage

Kink in oil pressure line? While doing the headers? Copper or nylon easy to damage

Part of the problem was a bad battery not spinning the engine as fast, oil pressure is good now with the new filter and new oil
I think might have had a stuck bypass? but we are all good now, just need to reset the valves. Hope this helps someone down the road

Want to update on this, still not happy with how long it takes to build pressure.
it takes over 30-40 seconds of cranking. It does build up but not like it use to.
So pulled the pan and took the pump out, opened the pump and it was clean inside
relief valve moves freely I can see oil up on the cam and pistons.
So I have pressure but why so long to build after no internal changes?
Thoughts and Thanks

Not sure what oil line you have to the gauge, but if its the small copper or nylon remove it and install the larger braided oil line. The gauge will respond much faster to cranking pressure and the blip of the throttle.

I won't EVER use the starter motor to build oil pressure, NEVER
That is a old SB Chevy SOP, think about how many RPM the motor is spinning over on the starter and then how many when running
Will the oil pump work better at 150 RPM or 600 RPM?
I also fill all my oil filters up completely (until they won't take any motor after soaking full many times ) with oil before mounting them on the motor, that way I don't have to worry about how long my motor will run with no oil pressure after changing the oil and filter

If you run the 1/8" plastic line, it is possible to restrict it by over tightening the compression fitting on either end. I once "dampened" an over active, jumpy gauge this way.Works but you have to sneak up on it.

How fast does it build if you just start it?

Hint....... I would stay away from cheap oil filters. Please use a wix racing oil filter.

The Wix racing oil filters bypass at least 20% more oil than their standard 51515 Ford, Mopar oil filters. I don't want trash being bypass into the motor
I use them,51515 filters now instead of the racing filters on everything I own except the race car that has a big remote mounted NASCAR type race filter

You can say whatever you want to say about any brands of oil filter or use whatever you want, but ...... use a filter that can handle the psi in a effective manner.

Have you split open a oil filter?
I have years ago(1973 or 1974) on the first Hemi stocker we where racing in NHRA stock, 50W Valvoline oil and 20F outside air temp breaking in the cam in the drive way at 2000 RPM, bang it split down the center, what a mess
As far as oil filters and bypassing, I like my motors to get clean oil, not with larger particle in it due to the filter bypassing 40% cold oil

When installing the
new hedders I had to raise the motor and looks like I dented the pan enough to have the pickup
make a witness mark on the bottom of the pan. Also had a thick layer of brown sludge where the pick
up sits (oil is Clean). Cleaned the pan and ready to put back together I hop it was just a combo of those 2.
No clue what the sludge was, not abrasive and no metal and yes I bent the pan back

How do you measure the bypass quantity?

Wix has stated that their race filters with internal bypass bypass 200 % more(40% vs,20% than the stock filters do, they have also stated that their stock bypass filter can bypass up to 20 % with cold oil at the lower air temps, below 40F.
No rumors or I think I heard kind of information from me!

Ok. You're not actually measuring, just using supplier literature. So the literature is saying that the valve is twice as big, so it can theoretically bypass twice as much. But in reality, it will only bypass the amount needed to control/balance the pressure differential dictated by the bypass relief. You will not actually know if, when, or how much oil is bypassed. Arguably, another good reason to not use a high volume oil pump and high viscosity oil.

I had a similar evasive pressure problem. Car would have pressure then lose it. Prime it with a drill and great pressure. Long story short it was a cracked pickup tube that finally broke off at the block (rb motor)

Same here except a hemi. Car would prime fine cold with a full pan of oil and be fine for quit awhile and hold 75psi until enough oil stayed in the top of the engine to get level below crack and would lose it's prime when the rpms were reduced.