oil presure??

npca-daner · Post by **npca-daner** » Wed Mar 17, 2004 8:01 am

Hello everyone- It has taken eight months, but hopefully this weekend I can get my "good" Patrol back on the road. The problem was that although it ran perfectly, it had only 2-3 pounds of oil pressure at higher rpm's after driving for a few minutes. It seemed to have better pressure at idle. I rebuilt the bottom end and hopefully this will solve the problem, BUT, I had this panic attack last night that maybe it wasnt the bottom end after all....The only other thing I can think of is that there may be a pressure release valve misfunctioning. Is there some sort of pressure release valve on the motor? (I had replaced the oil pump.) Any help, comments or witicisms would be appreciated.

npca-pudde · Post by **npca-pudde** » Wed Mar 17, 2004 3:51 pm

looking at my motor service manual..there is an oil pressure regulator on the oil pump...might need to check that before its installed...its on page 60 to 63 of the motor service manual. if by chance you dont have that book or cant get it off the net,let me know,ill scan the pages and email em to you....paul

npca-gary · Post by **npca-gary** » Wed Mar 17, 2004 7:23 pm

Daner, I had the same problem. Not quite that low though.. To make a long story short. I found that the oil pump was loose and was pumping most of the oil pressure right back into the oil pan. Removed the pump and "freed up" the pressure relief valve.( was sticking and not working properly.) Added another washer in the end of the relief valve,adding more pressure to the spring. Removed the bottom plate of the pump and carefully honed the plate flat removing all marks. Replaced the pump, tightly. I also replaced the Main Bearings. I have a lot of oil pressure and the engine sounds a lot quieter.

npca-daner · Post by **npca-daner** » Thu Mar 18, 2004 9:11 am

Gary/Pudde-thanks for the advise, I've done pretty much the same modifications as Gary to my oil pump and replaced the main bearings and turned the crank. I'll make sure to double check that the new oil pump is mounted correctly and that the pressure relief is working. The only other thing that I'm worried about is that someone modified the oil filter and it looks like a hack job.

npca-4x4xjonx4x4 · Post by **npca-4x4xjonx4x4** » Thu Mar 18, 2004 1:01 pm

What oil pressure is normal for the Patrols?

npca-riverpatrol · Post by **npca-riverpatrol** » Fri Mar 19, 2004 10:42 am

According to the owner's manual from my '66: "If the engine is under the proper temperature oil pressure guage indicates 3 - 4 kg per sq. cm. (42.0 - 57.0 lb/sq. inch), and by increasing the revolution of the engine the pointer of the oil pressure guage moves slightly."

npca-daner · Post by **npca-daner** » Fri Mar 19, 2004 10:51 am

I think we've had the "normal oil presssure" conversation somewhere in the past, I cant remember what Nissan calls for as far as oil pressure goes, but I'd say that you should be getting a minimum of about 10psi when hot, at idle, anything less and you may be starving some of the bearings of oil. At higher rpm's(highway speed) you should be getting a minimum of 20psi, it would seem to me that anything less at high rpm's would be hard on the motor and you may spin a bearing. this has been my experience with inline 6 motors, in chevys, patrols, and landcruisers. You can always cheat a little and go with a thicker oil to boost oil pressure, but I'm not sure if that actually helps the motor or just reassures the person looking at the oil pressure gauge...

npca-fud · Post by **npca-fud** » Fri Mar 19, 2004 2:40 pm

My 64 ran at around 60psi with new oil pressure sending unit, new oil pump, new gauge and fully rebuilt motor running a valvoline 50/50 synthetic blend. At very low rpm's it would not drop below 50psi. 10-20 psi and I would be seriously worried. Oil pumps run less than $200 new, sending unit around $50 and gauge is about $40 so why not just spend a few bucks and make sure the motor is well lubed under all conditions? Or perhaps $300 is less than you paid for your truck....

npca-4x4xjonx4x4 · Post by **npca-4x4xjonx4x4** » Fri Mar 19, 2004 7:12 pm

Wow... thats high oil pressure I would think. Mine runs about 30-40psi, and my motor has less than 50,000mi on it! Is your PC infected? Get a FREE online computer virus scan from McAfee Security.

npca-pudde · Post by **npca-pudde** » Fri Mar 19, 2004 8:48 pm

according to engine service manual...idle at temp is 7lbs...and 50 to 57 at higher speeds. mine is a different story...90 plus at high rpm's...and at idle..ive got 40 to 50.i use mobile1 15/50..original engine never been rebuilt...paul