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Oil pressure .....

Posted: Thu Jun 09, 2005 9:42 pm
by madrangie
It was suggested to me , to increase your oil pressure . You could either stretch the spring in the oil pump or put a small washer in under the spring . Now the second one is easy to do and quite quick . Now the reason i wanted to bring the oil pressure up a little is at idle i have next to no oil pressure . Sitting on a 100kph i have about 2 on the dial.

Can anyone tell me if this will have any adverse affects on the engine .

Posted: Fri Jun 10, 2005 8:40 am
by Philip A
What is proposed will do nothing for idling oil pressure. the pressure relief valve only opens when pressure is high =50PSI, to protect the filter.
If your oil light doesn't come on then don't worry be happy!!!
V8s don't need much pressure, and the only fix for low idling oil pressure is a new engine.
Regard s Philip A

Posted: Fri Jun 10, 2005 5:55 pm
by madrangie
Hmm what about a new oil pump first ? as the motor has only done 5k so far ..

Posted: Fri Jun 10, 2005 7:33 pm
by Philip A
WEEEELLL then
Did you not replace the gears and check the end float of the pump? Is the inside of the pump badly marked from metal bits from the cam?

Have you checked that your oil pressure gauge is accurate by putting a mechanics direct operating gauge on the sensor outlet? It sounds that your gauge does not have PSI calibrations even

The bad answer is that your cam bearings are worn and were not replaced in the rebuild.
But 3.5s only run about 15lbs at best on hot idle and the spec if I recall says 40lbs at 2500RPM. As long as you have the 40 lbs it is in spec. Do not be fooled by a red light flickering at idle. replace the sender before anything. Take it from a person who rebuilt an engine only to have the red light still on. AEEEEEGGGHHH
Regards Philip A

Re: Oil pressure .....

Posted: Fri Jun 10, 2005 9:58 pm
by Ralf the RR
madrangie wrote: Now the reason i wanted to bring the oil pressure up a little is at idle i have next to no oil pressure . Sitting on a 100kph i have about 2 on the dial.

Can anyone tell me if this will have any adverse affects on the engine .
1st thing, get another (calibrated) gauge on the thing. That will determine the next course of action.

2 on the gauge is 200kPa, which is about 30psi.
That's a little low, but probably OK.
(my 4.4 RR has 200kpa at idle and 300kpa at 100km/h)
Most V8 engines need flow, not pressure.

Since the engine is only 5K old, then there could be a number of problems.
Who rebuilt it?
Are they reputable?
Do they know what they are doing?

Problems could be:
Faulty pump.
Dodgy bearings.
Incorrect bearing clearance.
Incorrect bearing crush.
Faulty gauge/sender.

I'd get it checked out.
Your suggested fix only raises the bleed off pressure. That's not the problem (unless the valve is constantly open and bleeding a lot of pressure).

Posted: Mon Jun 13, 2005 7:17 pm
by Aquarangie
My 3.5 runs 20 psi at idle and about 35 psi at 100 km/h (about 2300 rpm). I had an issue with oil pressure and founsd that I had not torqued up the rocker gear bolts :oops:

Once I done this it was all good. There could be a multiple of symptoms that cause this, just a process of going through all the suggested problems as memtioned on this thread.

Good luck with it.

Trav