oil pressure problems

[peypey's ride]

Ok, so here is the deal. I did an oil change 2 days ago. I always run Castrol Syntec. Well, Advanced had a sale on Valvoline Full Synthetic, buy one get one free. So I got that and a new filter. Now, before this, my oil pressure at idle was 18-20 psi. After I changed the oil, its between 0-10 psi at idle! ! No oil light either! I have plenty of oil pressure in higher rpms. I did notice a slight vibration when I would leave a light until the oil pressure came up. So, i picked up Castrol the next day and changed the oil again. The Valvoline was already pitch black-shitty oil!!! Now with the Castro isl in, its still doin the same thing, just no vibration. I have no leaks and dont burn oil. What do you guys think maybe the problem? I am thinking the oil pressure restrictor spring my have broken. Cause when I am on the gas, pressure is up to 75 psi, as soon as I let off, the pressure drops like a brick to 15 psi then slowly down to 10 psi. Let me know what you guys think.

 

[peypey's ride]

Well I have a spare oil pressure regulator I plan to swap in. I dont know if this is a sign of the oil pump going out or not. If the oil pump stops working, will I still be able to build pressure or not?

 

[ndsti]

The oil pump is driven off the timing belt, when it goes you will notice. Do you still have the balance shafts?

 

[peypey's ride]

No. I dont have the BS. Everything was fine til I did the oil change. I started the car and all of a sudden low oil pressure! I dont get it? What made it do it.

 

[toybreaker]

How, and where are you measuring the oil pressure?

If you're topping out at around ~75psi hot, that shows the regulator is at least trying to do it's job, and there's sufficient volume at higher rpm's.

What's your cold idle oil pressure?

Was the pressure relief valve ported when the balance shaft elimination was done?

Removing the oil pressure relief valve and inspecting it and the passageways for a blockage/damage/restriction may be a good choice. There may be something hanging the valve open/not allowing it to return all the way.

Did you do any other maintainance, anything at all?

The second part of your description sounds like contaminated oil.

Does the oil smell like fuel?

Do you still have the old filter? Cutting that open may provide some information as to the source/makeup of the contamination, as there will be residue in the filter media.

How are you venting the crankcase?