I had an oil pressure problem with the 455 I installed recently. After break in I changed the oil to 10-40 Napa with a Napa Gold oil filter. I was experiencing about 50 psi during cruise and 30ish during idle before the change. The oil pressure then dropped to 40 during cruise to 20 during idle. I thought the motor was going away. I changed the oil agin with the same brand of oil and filter. No improvement. I also ran a magnet into the oil pan to look for metal. There was zero. I called my builder and he immediately asked what type of filter and oil I was running. He suggested a K&N filter with Valvoline 20-50 and a bottle of Lucas. I changed the oil and filter to his recommendations and voila! The oil pressure is a solid 45 to 50 psi at all levels of temperature and rpm. Now the valvetrain is as quiet as a mouse to the point I found I have slight header leak that I couldn't hear before. I am posting this so others don't freak out like I did. Quality counts.

 

Or maybe viscosity counts.

20W50 will give you higher pressures than 10W40.

I am tempted to say "Duh." but I won't.

- Eric

 

I would take the "duh". As long as my motor is ok. No offense taken. I think the problem was caused by the substandard oil filter. I put in the good oil for good measure. I should have stressed that in the post. I have found that a higher weight oil while initially will give you higher pressure, it will not maintain it. As it warms up as you know it gets thinner, (20-50) . The oil pressure problems I had were from the bad filter, not from bearing issues that can't be coverd up by adding Lucas. Once again I should have stessed that in the post.

 

The filter will also make a difference. I've never run a k&n but have run into higher pressure levels with a wix.

 

I don't have any experience with NAPA oil but I can tell you that their oil filters are excellent. WIX makes the oil filters for NAPA and the only other brand in the same league (in my opinion) is Purolator.

 

I never had any problems before with Napa either. Maybe I got one built on a friday in china.

 

In the boating world (bigger boats with diesel engines) NAPA filters and Chevron Delo oils are highly regarded.

 

I wasn't stating that the wix filter was bad, I was stating it maintained a higher pressure.

 

Honestly, I think it would be reasonable to try to change one factor and see whether that makes a difference.
It would be easier and cheaper to change the filter, since it will only cost the price of a filter and a quart of oil.
I wouldn't hurry to do it, but when you get a chance, it might clear up any questions to put on an identical NAPA filter and see whether it affects the pressure.

Objective data are always very welcome here, where we can spend weeks debating something like this, but put it to bed in minutes by actually testing our assumptions.

My bet is that it changes little if at all, but, hey, I've been wrong before.

- Eric

 

as was said WIX makes the NAPA filters. if you look at the WIX number it is the same as a NAPA Gold except that the NAPA filter is painted black and has one or two additional numbers added to it. I agree with Eric that you should try to change the filter alone and see what happens. also what filter and oil was in it during break in and what are the spec differences between them?

 

It occurred to me to just change the filter and see what happens, but I was going with the better oil anyway so I changed it too. I may have gotten a crappy filter. I haven't had any problems with Napa in the past. What I should do is throw that old filter back on it and see what's up.

 

Sure, if you've still got it - thats the easy way!

- Eric

 

I have seen defective oil filters before from all brands. The worst I have seen has been Fram and a/c delco. The best filters that I have used have been wix and napa (which is wix).

Your oil pressure sounds fine. I prefer to use 20-50w oil with a zinc additive.

 

Well, the oil filters were cut open before I could get them back. New motor inspection and all. The main reason I posted this anyway was the fact you should use the best you can afford. I think I got a defective filter. I took the car out last night. Oil pressure is 50 psi when hot and at speed, 30 psi at idle. Just the way it was before all this started. Round and round I go, where I stop is exactly where I started. LOL!