Is this normal

roofman · Post by **roofman** » Tue Oct 11, 2011 5:41 pm

Hi guys i aint posted for a while so i kinda feel cheeky with a question

....My oil pressure has slowly over a period of 6 months been dropping and now ime down to 20 psi on normal road rpm's,i have a 90 Rangie with a 3.5 and all though i have no knocks or taps i thought ide better have a looksie..after taking the pump apart and stripping the relief and cleaning ime not happy with the scoring on the cover but need to ask you chaps 1st before my hand goes near my back pocket...Does this look normal or could it be the reason for reduced pressure????
also does a stiffer spring increase pressure on the relief so would a shim under the big nut increase oil pressure???
cheers
Brian

EDIT....how can i insert an image from my documents[/url]

Alley Kat · Post by **Alley Kat** » Tue Oct 11, 2011 9:25 pm

Brian, if you hoik the pic onto Photobucket or something, you can copy the link code they give, and paste into a post here. It'll look something like this-

Code: Select all

[img]http://www.somewhere.com/yourpic.jpg[/img]

hth
cheers
Bill

DaveEFI · Post by **DaveEFI** » Tue Oct 11, 2011 10:43 pm

Before you go mad, would be worth checking the pressure with a known good gauge. Just in case yours is dying.

kiwicar · Post by **kiwicar** » Wed Oct 12, 2011 10:48 am

Hi
If you can spare the time you can always resurface the oil pump face of the cover with a piece of wet and dry and a flat surface takes a while but costs you about 50p for the paper.
But as said above check it is the pump at fault.
Best regards
Mike

Ian Anderson · Post by **Ian Anderson** » Wed Oct 12, 2011 1:50 pm

The old favourite - 20/50oil?

Ian

Post by **katanaman** » Wed Oct 12, 2011 2:33 pm

all of the above really plus if you are having oil pressure problems no amount of shimming is going to bring the pressure up. Its a relief valve so if your never making the pressure in the first place it cant increase pressure. You could block it off all together and it would make no odds.

What mileage is on the engine? What oil are you using and when was it last changed?

roofman · Post by **roofman** » Wed Oct 12, 2011 6:01 pm

thanks for the replys guys but i think ive licked the problem..i took the relief apart and cleaned the valve with a bit of wet n dry then replaced it with a couple of washers for good measure...i then milled the face by a thou or two and returned it to true flat which just about removed the scoring. checked the gears which were within spec and replaced with a good packing of vasoline,what i did find on removal was 2 cover gaskets

which was not good..Anyway removed dissy and after an oil change and filter (10/40) i brought the pressure up with a modifed stem and drill,replaced dizzy and fired the motor up...RESULT..50 at 3000 and a nice drop down to 25@ idle (hot)...With reference to "check the gauge 1st" post,good advice which i did with a good known air supply and it seems spot on give or take 1-2 psi either side..
thanks again
Brian

RoverP6B · Post by **RoverP6B** » Wed Oct 12, 2011 8:54 pm

Hello Brian,

The 10w40 oil that you are using is the incorrect viscosity for the RV8 when running the camshaft driven oil pump.

The correct grade is 20w50.

Ron.

DaveEFI · Post by **DaveEFI** » Wed Oct 12, 2011 9:52 pm

RoverP6B wrote:Hello Brian,

The 10w40 oil that you are using is the incorrect viscosity for the RV8 when running the camshaft driven oil pump.

The correct grade is 20w50.

Ron.

From my BL SD1 workshop manual:-

To August 1983 - 15w40

From August 83 - 10w40

IMHO, far too much emphasis is put on oil pressure. It's the flow rate through the bearings etc which matters.