another oil pressure problem

4montecarlo · Jan 19, 2007

i put a 87 ho 302 into my stang to drive this winter
the motor had 140k on it and all i did was put it in and run it with a
hp or hv pump out of my old 302
everything was good, I had about 80 psi cold start, 60 psi cruise on highway, and 30 pis warm idle
than all of a sudden, the mechanical gauge started to flicker prob half of the time while driving it, i still had my good pressure, but it moved very rapidly.
Over the 2 weeks, i havent done much, but the pressure has dropped to 20 on warm idle, and 40 on cold startup and 30 on highway cruse.
Also on startup now, it takes prob 10 sec to get pressure, its similar to when you change oil and filter, and you have to wait on the filter to fill with oil, unless you prefill it.
So this weekend, i finally have some time to check it out, what should i look for?
and i have a ford racing mechanical gauge, so i think the pressure # are accurate.
I was thinking about checking the oil pump ds first, but after that, what else should i check w/o tearing that much apart? Do an oil change, its a wix filter, not a fram.
thanks
matt

JimBowy · Jan 19, 2007

consider trying another gauge before doing much else....
at this point you still enough "enough" pressure at idle to be safe....

4montecarlo · Jan 19, 2007

well the stock gauge is showing the highs and lows to match the autometer gauge, so i believe it is accurate. but this i emailed autometer, they suggested to use air pressure to test the gauge, so i will add that to the to-do list this weekend
and due to having some pressure is the reason i have been able to drive th car still
thanks
matt

OWENMUSTANG · Jan 19, 2007

If you still have the stk oil pump drive, i'd say you have your 1st suspect...
filter is another one..

why do you need a hv/hp oil pump?

4montecarlo · Jan 20, 2007

thats what was on the motor when i purchased the car, it is either a hv or hp, not sure which, i dont have the part number and i didnt buy it, so its not the stock oil pump, but still could be the problem
matt

4montecarlo · Jan 22, 2007

well changed oil filter, no better
pulled out the dizzy and i ordered an oil pump primer to spin the oil pump with a drill
how can i tell if the shaft is just wore down? and why would it happen just so suddenly?
thanks
matt

Ren da Noob · Jan 22, 2007

ShowNGo93 · Jan 22, 2007

The oil pump ds usually will not wear to create low oil pressure, they usually twist like pretzels after installing HV or HP oil pump..you'd probably have no oil pressure if that happened.
Try the oil pump priming tool, be sure to spin it COUNTERCLOCKWISE, that'd be a good start to see if the guage is reading the same as when its running..Be sure to do a cold prime and if you can, reinstall the dist. and run the car until warm, pull dist. and do a warm oil prime with the drill. See where you're at then...

barrylee66 · Jan 22, 2007

that happend to me on the interstate pulled over and was 2 quarts low. I am sure you checked that already.

THE WIZARD · Jan 23, 2007

You could have cracked the block. That would cause the shaking oil pressure.
If all else fails pull the motor & pull pan and check for cracks near mains.

4montecarlo · Jan 26, 2007

well got the oil pump primer and went to work with my drill
upon startup, i had 80, within secs oil pressure dropped and begin swinging
the movement was not as quick as it is with the car running but still movement was very obvious
i would assume its all in the pump than, since thats all thats moving, any other ideas?
thanks
matt

AKRON HORSEPOWER · Jan 26, 2007

4montecarlo said:
well got the oil pump primer and went to work with my drill
upon startup, i had 80, within secs oil pressure dropped and begin swinging
the movement was not as quick as it is with the car running but still movement was very obvious
i would assume its all in the pump than, since thats all thats moving, any other ideas?
thanks
matt

I have only found 2 ways that it does that 1 cracked block,2 junk stuck in the spring in pump. In your case I would think junk in spring. Just something 2 check.

bama 5.0 · Jan 27, 2007

you couldive washed out the bearings. if you arent runnin a 7 qt oil pan a hv pump will suck a 5 qt pan dry very quickly.

4montecarlo · Jan 31, 2007

hm, well this weekend, i changed the oil and problem went away
i put some cheap oil in just to see if something was stuck that would come out with a oil change, watched the oil drain, no chucks or large particles of any kind, so i though it was a waste, but when i cranked it back up, i had 80 psi. since i have had the same pressures i used to have before whatever happened. could the oil have gone bad? the usual amount i dump came out when drained the oil pan, the oil only had about 1500 miles, and it looked dark, but not burnt or anything?
well, thanks for the replies
matt

lone sailor · Jan 31, 2007

Keep us informed of your ongoing oil pressures. It could still go back to being relatively low with no warning.

4montecarlo · Apr 11, 2007

yup, it happened again, prob had less than 1000 miles since oil change
this time the oil had brown streaks in it, and had a faint sent of gas
i assume i am getting gas into my oil and diluting the oil
so, the question is how am i getting gas in my oil? I kind of assume the cylinders are getting washed down with gas, how can i verify that? or i think i read that the fp regulator might be going bad if oil smelled like gas?
thanks
matt

RI lx · Apr 12, 2007

cracked oil pick up tube,or improper clearence between pick up and pan or failure of the pick up to pump gasket.

85ascMcLaren · Apr 12, 2007

Are U FI or Carb. If carb, your mech. fuel pump may be leaking. dumping gas in the oil, but if that were the case, your crankcase would load up fairly quick with gas and you would smell it out the exhaust as well.....

Jason

4montecarlo · Apr 12, 2007

fi
my friend said he could smell gas from my exhaust, but i dont smell anything while the car is running
RI lx - but why would putting fresh oil in the oil pan return proper oil pressure
i still think the oil is getting contaminated with something as i drive i
thanks
matt

RI lx · Apr 13, 2007

I don't know, just thowing out suggestions as to what could be the problem.

I thought when you originaly posted about changing the oil solving the issues, you came back and said it started happening again.

fluctuating presure sounds like the pump is cavitating, which could be caused by a crack in the pickup or a leak at the pump/pickup interface causing it to suck air. Or, the pick up could be too close to the pan, alowing the suction to flex the pickup enough to touch the pan and block oil flow, then release and so on...there could be crap (old gasket material) in the pan that is blocking the screen that flushed off in the oil change only to be sucked back up later.

Any of the other suggestions could be the cause as well, I'm no expert.

another oil pressure problem

4montecarlo

JimBowy

4montecarlo

OWENMUSTANG

4montecarlo

4montecarlo

Ren da Noob

ShowNGo93

barrylee66

THE WIZARD

4montecarlo

AKRON HORSEPOWER

bama 5.0

4montecarlo

lone sailor

4montecarlo

RI lx

85ascMcLaren

4montecarlo

RI lx

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