if one were running 30W and then changed to a heavier weight 50W should the oil pressure increase or does the pressure stay constant no matter what viscosity oil used.
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if one were running 30W and then changed to a heavier weight 50W should the oil pressure increase or does the pressure stay constant no matter what viscosity oil used.
Higher viscosity oil will result in higher oil pressure - often enough to blow a cheap canister oil filter. I could see 40W in summer for air cooled but suspect 50W is excessive (unless engine on last legs). Higher pressure may result in harder engine starting and lower fuel economy. Higher viscosity would result in less oil leaks!
A fair number of higher performance engines will use strictly 50 weight oil, think Valvolene racing oil. I just yesterday bought 2 gallons at $4.69 a quart for one of my engines...I have two engines that run on 50 weight....but.....not for normal street engines where it gets cold....it gets pretty warm here in the summer and 50 weight keeps the pressure up at idle on very hot days.....oil temps of 230 degrees or less. Thicker oil maintains better oil film on heavily loaded bearing surfaces, but does take more HP to run the engines. And makes for excessive oil pressure on cold engine starts....
If your oil pressure at idle speed of say 750rpm, engine at normal operating temp, and in good overall condition, drops below 10 psi or so, a thicker oil may be a proper consideration. Accurate oil temperature as well as accurate oil pressure should be known. If oil is too hot, (or too cold for that matter) that needs to be corrected before considering changing oils. Also, multigrade oils are recommended by most car makers, for good reasons...
If your oil pressure at idle speed of say 750rpm, engine at normal operating temp, and in good overall condition, drops below 10 psi or so, a thicker oil may be a proper consideration. Accurate oil temperature as well as accurate oil pressure should be known. If oil is too hot, (or too cold for that matter) that needs to be corrected before considering changing oils. Also, multigrade oils are recommended by most car makers, for good reasons...
this post is in reference to my Tiger Ford 260 (stock), 73K miles.
I am running Brad Penn 10/30W and at idle it is at 20 and on freeway it is a tad over 40. Would a heavier oil in the summer months kick the oil pressure up a bit, especially at idle.
I am running Brad Penn 10/30W and at idle it is at 20 and on freeway it is a tad over 40. Would a heavier oil in the summer months kick the oil pressure up a bit, especially at idle.
Bob, 20 PSI oil pressure in a V8 at idle seems about perfect, and 40 PSI runnin' down the road is fine also. Why do you feel that you need more pressure?
I dunno, I get anal about some things. Pressure sounded low but maybe its normal and im just looking for "problems".
Car runs great so I will keep the pedal to the metal. Cant afford a engine rebuild at this time, thanks.
Car runs great so I will keep the pedal to the metal. Cant afford a engine rebuild at this time, thanks.
Bob:
Friggin thing is PERFECT!
Stop worryin' and drive the thing....
10W20-30 in Winter, 10W-40 in summer. (or read your owners manual for the same info)
Friggin thing is PERFECT!
Stop worryin' and drive the thing....
10W20-30 in Winter, 10W-40 in summer. (or read your owners manual for the same info)
as long as you have ten psi for every thou rpm your running thats all you need that means 3000 rpm should be 30 psi. bill
The 10 psi per 1,000 rev's is correct. 40 PSI at freeway speeds is more than enough pressure.
Too much pressure will damage bearings. High pressure Oil squirting though passages and hitting the bearings will cause a score line to develop in the bearing where the oil hits it.
Too much pressure will damage bearings. High pressure Oil squirting though passages and hitting the bearings will cause a score line to develop in the bearing where the oil hits it.