SBC oil pressure.....

mrvette

Phantom of the Opera
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I have what seems to be a fresh engine in a motor home I been fixing on for almost 2 years....

so I took it on the road yesterday, and one of the things I noted is the bad news on oil pressure, or at least I think it's bad news....it goes to 40 psi when 'cold' but after a blast in 90f ambient heat and traffice back home, the oil pressure was down to 20 psi at idle...30 at 2k rpm....

problem, or ignore it?? put in some STP and foregetaboutit??

maybe that oil filter bypass thing the filter screws into??

engine smooth and quiet as a mouse otherwise....and it's clean in and out....

:bonkers:
 
I've always gone by the general rule -10 psi per thousand RPM....And I've read any more will cost you horsepower...

20 PSI should be fine-

Richard
 
I've always heard a SBC only needed 7psi to keep metal off metal. I would not sweat 20 pounds, especially at idle.
 
I've always gone by the general rule -10 psi per thousand RPM....And I've read any more will cost you horsepower...

20 PSI should be fine-

Richard

I've always heard a SBC only needed 7psi to keep metal off metal. I would not sweat 20 pounds, especially at idle.

Not really doubting what you guys say, but all other engine I have had run almost twice that psi....used to seeing say 50 psi at 2500 rpm....

I have heard it don't take much pressure to float a bearing, but this one is rather unique over the years....makes me nervous....

:fishing:
 
I've always heard a SBC only needed 7psi to keep metal off metal. I would not sweat 20 pounds, especially at idle.

I don't believe its the pressure that floats the shaft. I automated a small hydro unit years ago. The bearings were non pressurized oil "slingers". You could move those pelton wheels by hand. Once you got them going just a few inch/sec you could feel the friction diminishing. The motion of the oil film creates hydraulic lift.
 
On C-4 LT-1 engines the shop manual has the idle minimum oil pressure (hot) at 5 psi...(5W30 oil).
 
OK guys, I'll send you all the bill when/if it blows.....

:sweat::tomato::crutches:
 
I recently had some experience with oil pressure issues....

I have an 04 Tahoe, and as it has 135K miles on it, so I decided to do the oil change myself this time vs. going to the dealer where virtually all the work has been done on this truck before. I did the change and used a Fram oil filter. I know, some folks don't like those filters, but stand by. Shortly after that oil change, say 1500 miles or so, I noticed the oil pressure was below 40psi at about 2100 rpm, and much lower, sometimes under 20 psi at idle. Then I started hearing tapping occasionally, like lifters going bad. Finally, if the truck would sit for several days without being run, it'd take so long to build oil pressure, bells and whistles would go off for low oil pressure.

I did some research on the LS engine oiling system, and thought the oil pressure bypass spring or oil pump could be an issue. Called the dealer and they said they had seen oil pressure issues in the LS engines before, and that there were testing procedures they could do. I went this route because if it needed an oil pump, I don't have the time to do it myself so they'd have to do it anyway.

They call me and said "do you know you have an aftermarket oil filter on here?". I told them I did, and they recommended going only using an AC Delco filter. They did the oil change, and some other things like injection system flush and so forth. I'll tell you this. I haven't had a problem since. Oil pressure is as it was when it was new, and it doesn't matter how long the truck sits, oil pressure is nearly immediate.

So Gene, if this is new for the Clamper, could it be a filter issue, sending unit or guage??
 
Since we're already hijacking the thread, I will put a SuperTech (Wal Mart) filter on either of my Vettes before I'll put a Fram on there. After doing some research I found that there are really only about four companies that actually manufacture the filters and all these other brands you see are really just repackaged filters. The SuperTech is made by Wix, I believe, and Wix is the manufacturer of that brand, Purolator and several other name brands you see in the filter isle.
But given the option, I generally go with Baldwin. They're a major manufacturer but are generally commercial stuff. They make pretty much any filter you need but they don't sell them in all the parts stores. I had a commercial account for my business and used them on our equipment. I saw the quality they make so I would just buy what I needed for the maintenance on my cars as well as my work truck through them. Good stuff.
 
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