Oil Pressure Issues
Thread Starter
Intermediate
Joined: May 2015
Posts: 31
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From: New Jersey
Oil Pressure Issues
Hey everyone, so the other day I blew an oil line that ran a mechanical oil pressure gauge under the hood in my '76 and the oil pressure hit 0. I found a cap and put it where the line originated from so I could have a fix that would work until I buy a new line for the gauge, however; my oil pressure is now reading just above 20 psi (25-30 area) when I idle after driving for a while. It gets up to about 60 when I get on the pedal. If I'm cruising it reads right above 40.
Anyone know what I should check first? I replaced the oil and it's full. I was just wondering if this was a normal range for a '76.
Anyone know what I should check first? I replaced the oil and it's full. I was just wondering if this was a normal range for a '76.
Last edited by Jong76; May 17, 2015 at 01:35 PM.
Intermediate
Joined: May 2012
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From: Over The Hills And Far Away
If you lost all the oil and it ran dry, you could have done some damage to the main/rod bearings. Does it make a "tapping sound"? How much is the oil pressure down from before the blow out?
Le Mans Master
Joined: May 2002
Posts: 5,086
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From: Lebanon Township New Jersey
The oil pressure readings now are normal. When you broke the line that connects to the oil pressure gauge, of course the gauge reading will drop to zero immediately. That doesn't mean that your engine suffered from low oil pressure unless it ran long enough to lose several quarts.
Thread Starter
Intermediate
Joined: May 2015
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From: New Jersey
I thought It did for a second, but I turned my Jeep on and it sounds the exact same mechanical wise.
And I know I lost a decent amount, but I also caught it fairly quickly after it happened.
And I know I lost a decent amount, but I also caught it fairly quickly after it happened.
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Team Owner
Joined: Jan 2006
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From: Crossville TN
If your engine has the stock Chevy oil pump, it will read fairly low at idle.... 10-15 psi. When you raise the rpm's, the pressure will increase. From your description, your oil pressure readings are normal for a Chevy oil pump.
P.S. I would be surprised if your idle oil pressure previously read 40 psi (if you have a Chevy oil pump).
P.S. I would be surprised if your idle oil pressure previously read 40 psi (if you have a Chevy oil pump).
Thread Starter
Intermediate
Joined: May 2015
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From: New Jersey
I can't be certain that it is a factory pump.
But in regards to the "ticking" could it be as simple as low oil? I mean, my dipstick reads good, but that still leves the noise. I just changed the spark plugs, and she doesn't like starting already, and idles slightly rough. Could it just be a spark knock from improper detonation? I put Autolite Platnums in it, anyone got any experience with these?
But in regards to the "ticking" could it be as simple as low oil? I mean, my dipstick reads good, but that still leves the noise. I just changed the spark plugs, and she doesn't like starting already, and idles slightly rough. Could it just be a spark knock from improper detonation? I put Autolite Platnums in it, anyone got any experience with these?
Intermediate
Joined: May 2012
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From: Over The Hills And Far Away
"If" you ran the oil pan dry, and drove the car with no oil pressure, you may have done damage to the motor, you may have damaged the main/rod bearings witch would give you a tick (soon to be a knock) and also "clearance" the bearings giving you lower than normal oil pressure. Did you have the noise before the lose of oil? Does the noise get louder with increased rpm? What is oil pressure at idle now vs before? What is your oil pressure at cruise speeds now vs before? How many miles are on the motor?
Thread Starter
Intermediate
Joined: May 2015
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From: New Jersey
Yes, it gets louder as the rpms go up. And the oil pressure was typically at 40 before at idle, 60+ under load. It's at 20 at idle, and 50+ under load now. But if it's the factory pump, that appears to be the normal range.
But I've heard about people getting a tapping sound from the spark plugs not operating correctly too. I put platinum spark plugs in there if it makes any difference. Changing them out soon.
But I've heard about people getting a tapping sound from the spark plugs not operating correctly too. I put platinum spark plugs in there if it makes any difference. Changing them out soon.
Race Director
Joined: Dec 1999
Posts: 11,096
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From: Sierra Foothills CA
"If" you ran the oil pan dry, and drove the car with no oil pressure, you may have done damage to the motor, you may have damaged the main/rod bearings witch would give you a tick (soon to be a knock) and also "clearance" the bearings giving you lower than normal oil pressure. Did you have the noise before the lose of oil? Does the noise get louder with increased rpm? What is oil pressure at idle now vs before? What is your oil pressure at cruise speeds now vs before? How many miles are on the motor?
I wish I could tell you otherwise, but I also suspect you've hurt your engine. Normal oil pressure with a stock pump may not be relevant in your case. Example- when I went through the 427 in my '69 my engine builder put in a higher pressure pump than stock and we relieved the drain back holes in the lifter valley to facilitate quicker drain back to the pan. If anything like that was done to your engine, stock pressures and the old 10 PSI per 1000 RPM levels won't matter to you. What does matter is that the pressure has dropped significantly compared to what your norm used to be. There's a reason for this and it's probably what is described in the post I quoted. Yes, it gets louder as the rpms go up. And the oil pressure was typically at 40 before at idle, 60+ under load. It's at 20 at idle, and 50+ under load now. But if it's the factory pump, that appears to be the normal range.
But I've heard about people getting a tapping sound from the spark plugs not operating correctly too. I put platinum spark plugs in there if it makes any difference. Changing them out soon.
But I've heard about people getting a tapping sound from the spark plugs not operating correctly too. I put platinum spark plugs in there if it makes any difference. Changing them out soon.
Last edited by Les; May 18, 2015 at 07:18 PM.
Thread Starter
Intermediate
Joined: May 2015
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From: New Jersey
Yeah, I'm leaning the same way you guys are, but I like to live by "expect the worst, hope for the best." So I'm hoping it's the spark plugs just tweaking out.
On the bright side, if it's the main bearings and rod bearings, I have an excuse to put new pistons in it while I'm at it right?
What do yall think of this kit I found? Good kit or nah?
http://www.northernautoparts.com/par...FYwXHwodb54AVw
And yeah, I got a few friends who can help.
On the bright side, if it's the main bearings and rod bearings, I have an excuse to put new pistons in it while I'm at it right?
What do yall think of this kit I found? Good kit or nah?
http://www.northernautoparts.com/par...FYwXHwodb54AVw
And yeah, I got a few friends who can help.
Thread Starter
Intermediate
Joined: May 2015
Posts: 31
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From: New Jersey
So I investigated the ticking more and took a video, that it won't let me upload. But i had a buddy with me at the time that suggested a blown exhaust gasket. Any opinions on that?
Race Director
Joined: Dec 1999
Posts: 11,096
Likes: 990
From: Sierra Foothills CA
I say that tongue in cheek because, unfortunately, they have nothing to do with one another.