is the oil pressure too low?

It has been a long time since I posted here. I have a 283 sbc out of a 66 chevelle installed in my '57 Willys CJ5. It has been completely rebuilt to stock with 305 heads, Edelbrock performer intake and carb, stock oil pump and pan, stock cam. I did not want a highly modified engine since the jeep has such a short wheel base and I am running the stock T90 3 speed tranny with a Dana 18 T-case ( I figured a stock 283 would do just fine for a jeep designed for an F-head 4 cylinder). I have about 1300 miles on it. The oil pressure gauge reads around 20 psi at fast idle (maybe a little more) and around 12 psi at warm idle (700 rpm). When driving at around 2000-3500 rpm the pressure reads anywhere from 25-35 psi. Are these pressures OK? I did a search and could not find out anything on the normal pressure (numbers varied a lot). I just changed the oil tonight and put in Mobil 1 10w-30 synthetic (used Castrol GTX for the break in). I wanted to put in a Wix filter but couldn't find one locally so I used a K&N filter. I don't hear any knocking or grinding coming from the engine and it seems to run well (other than fine tuning the Edelbrock)

Thanks.
Paul

First thing you need to determine is how accurate your gauge is. Is it mechanical or electrical? I just had a sender go out on my 27 and it started reading low, so I temporarily put a mechanical gauge right where the sender went on the block and it read 50-60 at idle. Replaced the sender and now it reads fine.

Just a thought.


Don

Mechanical gauge. It bounces around like it is working. Is there a normal operating pressure?

The guys on here who are really good at engines will be able to give you a better answer, but I am old school and like lots of oil pressure. I grew up stretching the relief springs in oil pumps so they would put out 80 pounds, so that is my education. Today, I understand the current thinking is that too much oil pressure isn't necessarily desirable........something about it blowing the oil past the bearings too fast. At least that is what we were told relative to marine engines when I was in that business. They told us 25-35 is absolutely fine at higher rpms, these days.

But I still get nervous when mine dips below 45 pounds. We'll see what some others say, who know more than me.

Don

check gauge but 20to30 off idle is fine for a stock mild build with stock oil pump long as it builds psi oil as rpm moves up

I will check the gauge tomorrow. I have to buy a gauge to check it with tomorrow.

I was hoping Pat would see this thread, he would know for sure. As for the gauge, I just bought one of the inexpensive mechanical gauges and it has the same (1/8 npt) thread (I think) as the place where the sender went. So I just put a nipple and coupling on it and screwed it right into the block. As soon as I fired the engine up it climbed right to 50-60 psi so I knew it was my sender. That is all you will have to do too.

Don

I checked AZ and AA and a local parts store. They only have pressure gauges to install in the dash. I think I may have to buy one from Summit and wait for it to get here. By the way, where is the oil pressure gauge take off from the engine?

you do not have to mount it just hook it up and look at it see what you have them you could mount it or tape it up on the wind sheild for a check .then take it off then hook old one back up then you can work out the dif of the two gauges

does the oil line ever get clogged up? The one that goes from the engine to the gauge. Also, I assume I should use some sealant tape when I put the connector back in the engine block (yes? or rtv?)

The stock idiot light sender on a 283 was set to illuminate at below 6 psi if memory serves me correctly. Yours is fine. as long as the lifters dont clatter, I would leave it alone. The only worry with the jeep is a steep uphill/down hill where the oil runs away from the pickup.....and oil pressure doesnt help that.

mike in tucson

Quote:

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Originally Posted by md85

I checked AZ and AA and a local parts store. They only have pressure gauges to install in the dash. I think I may have to buy one from Summit and wait for it to get here. By the way, where is the oil pressure gauge take off from the engine?

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No, you are missing the point. The gauge from Autozone and Advance IS the one you want. Although it is made to go in a dash the threaded part on the back where the line normally goes will screw into a standard pipe fitting, like your block has. Buy that one and use it temporarily and then if yours is bad you can put the new one right in your dash.

The oil sender on a sbc is right next to the distributor or sometimes on the side of the block near the back.

Don

I guess I was wrong. The oil pressure gauge is electric, or so it seems. There is a sender just next to the distributor. Perhaps it is going out..that starts the whole debate about electric versus mechanical.. It is a tight fit to the sender. pic of it during the build and installed.. I just spoke with someone who said 10 psi at idle and warm (especially in this heat) can be normal for a sbc. By the way..sender is for a Jeep as is the gauge..

http://i991.photobucket.com/albums/a...n/IMG_0888.jpg

http://i991.photobucket.com/albums/a...n/IMG_0817.jpg



By the way, I tried to post a pic but for some reason it only gives a link. Does it have something to do with the IMG code off or HTML off?

Pic of my jeep before body.....it looks like I dont have oil pressure sender or distributor in yet.
Attachment 50378
mike in tucson

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Originally Posted by robot

Pic of my jeep before body.....it looks like I dont have oil pressure sender or distributor in yet.
Attachment 50378
mike in tucson

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Nice jeep...got any completed pics?

Attachment 50379

This is different wheels and tires.....on my fourth set of tires in 2500 off road miles......

low O/P with engine on its nose your pick up is in the rear so probably not getting much oil to make O/P

That pic is probably a 45 deg slope...it doesnt look steep in the pic. Runs fine oil pressure at that attitude.....it's the steeper ones I worry about. It has a Mororso accumulator that operates via solenoid valve off the oil pressure sender but I have never used it. Usually, when you are dropping off a 5 or 6 ft vertical (90 degree) drop off, the engine is at an idle and not much is happening (except the pucker). I dont have the guts to go off the 10 ft verticals.....they put the xfer case in front wheel drive and gun the engine as it hits to pull the front out so it doesnt endo. Kenny Davis probably has the eggs to do the big drops. The little hill in the picture stops most amateur quad riders, by the way.

Stock sbc'sl, ie stock oil pump, won't run alot of pressure. 12psi warm at low idle and 30 to 35 running down the highway is perfectly normal. But I may be like you that warm idle pressure always bugged me. But I have 100,000's of miles on many of them with that kind of oil pressure.

by the way, is there only 1 port to check the oil pressure? I mean so I don't have to squirm in the tight place to remove the current sender.

Some older blocks have a plug above and to the left of the cam on the top front before the intake this will give you an O/P reading too if block is old enough to have it.

I don't know what is "normal" for a sbc but the one I had in my 23 idled at 45 and got up to 70 going down the road. One thing you might have is a mismatch between the sender and gauge. Gauges require a certain ohm rating on the sender, like 90-270 or something similar. If the sender is not what the gauge wants to see the readings will be off. Stick the mechanical one in there and test it, then you will know.


Don

Got some Brad Penn oil, 10w-40, and a new wix oil filter. Runs at about 40-ish while driving at around 2K to 3K. Think I will stick with the brad Penn for the Zinc ('66 283 sbc). Seems to be running fine with the current setup.