no oil pressure after changing head gasket!!! why??

[terryd001]

got it in and now boom 50-60psi and the chattering simmered down. gonna finish putting everything back together tomorrow. sounds like its running a lot better. thanks for the help everyone

[91CoupeMike]

http://www.dragstuff.com/techarticles/vacuum-pumps.html

[jyro]

from that page

http://www.dragstuff.com/techarticles/vacuum-pumps.html

"How does running a vacuum pump affect oil pressure?
I don't personally believe that a vacuum pump affects oil pressure that much from a physics point of view, because if you have atmospheric pressure in your pan or more or less pressure, it's still the same throughout the motor. It's a balance regardless of how you look at it on both intake and outlet sides of the oil pump. Normally racers won't experience any issues with oil pressure fluctuations or changes when using a vacuum pump on a wet sump engine."

[91CoupeMike]

"How does running a vacuum pump affect oil pressure?
I don't personally believe that a vacuum pump affects oil pressure that much from a physics point of view, because if you have atmospheric pressure in your pan or more or less pressure, it's still the same throughout the motor. It's a balance regardless of how you look at it on both intake and outlet sides of the oil pump. Normally racers won't experience any issues with oil pressure fluctuations or changes when using a vacuum pump on a wet sump engine."

Yeah I read it, so with all he has to say, I should be able to add a vacuum pump to my car without any modifications and it could pick up some power, said low tension rings aren't needed but if you have them you'll see lager gains

[racrguy]

Yeah I read it, so with all he has to say, I should be able to add a vacuum pump to my car without any modifications and it could pick up some power, said low tension rings aren't needed but if you have them you'll see lager gains

You answered your own question above.... You had a vacuum line hooked up to the crankcase, when you got it to idle you lost oil pressure. Remove the vacuum and it idled and had good pressure. If what the guy said in the link is right, don't you think it wouldn't have made a difference in your pressures?

Don't ask for an explanation, get one, then find something to the contrary and ignore your own evidence that proves what I said was accurate.

I don't have a problem with you, but when you post shit like that it grates my nerves.

[91CoupeMike]

Whoa man I wasn't arguing with anything, I posted a link up.

My car was surging when it was losing oil pressure, like stumbling and falling at its face if you tipped in pressure would resume. I'm not for sure if that was due to the vac line or not because it was actually like that when it was tuned. I wasn't thinking correctly before, mistake.

The car actually ran fine like that, but I wasn't aware that crank vacuum is actually a good thing. With a pump I would have 10-15 in at wot as well, right?

I think you guess think I'm trying to be "corrective" I'm not in anyway, maybe it's just my way of inquiring because if I am wrong then correct me, and if I don't understand, help. Lol

[racrguy]

Whoa man I wasn't arguing with anything, I posted a link up.

My car was surging when it was losing oil pressure, like stumbling and falling at its face if you tipped in pressure would resume. I'm not for sure if that was due to the vac line or not because it was actually like that when it was tuned. I wasn't thinking correctly before, mistake.

The car actually ran fine like that, but I wasn't aware that crank vacuum is actually a good thing. With a pump I would have 10-15 in at wot as well, right?

I think you guess think I'm trying to be "corrective" I'm not in anyway, maybe it's just my way of inquiring because if I am wrong then correct me, and if I don't understand, help. Lol

The reason your car was running like shit was because it was getting unmetered air. What you would do is run a vacuum guage where you could see it, run the car through the top of the RPM range and check crankcase vacuum, and run a popoff valve if need be to keep it from building too much vacuum.