Low oil pressure
Thread Starter
Melting Slicks
Joined: Nov 2001
Posts: 2,659
Likes: 7
From: Katy (Houston) TX
CI 7-8 Veteran
Low oil pressure
Wanted to run this buy you guys/gals and see if you can tell me what the problem is. After just starting engine (or when it hasn't gotten too hot) the oil pressure seems to be just fine (middle of the gauge). But when it gets a litte hotter or when I've been on the highway for a few minutes the oil pressure drops to nearly 0 on hard acceleration and at idle.
I was thinking maybe rings???
[Modified by tshort, 3:35 PM 5/13/2002]
I was thinking maybe rings???
[Modified by tshort, 3:35 PM 5/13/2002]
Instructor
Joined: Oct 1999
Posts: 139
Likes: 0
From: So. Miami
Re: Low oil pressure (tshort)
I'm pretty sure worn rings would not cause a pressure drop--they are not on the "pressure" side of the lube system. Bearing on the other hand....worn bearings would affect pressure. Pressure relief spring too????
Safety Car
Joined: Apr 2002
Posts: 3,551
Likes: 0
From: No link, No dupe
Re: Low oil pressure (tshort)
I have to agree with 7tea1, regarding the bearings being bad. Bad rings would only make the engine smoke, and reduce power. Could be a problem with the oil pump, but wouldn't it make bad pressure all the time? Do you hear a ticking when the engine is at idle with near 0 pressure? If so, that may indicate that the gauge is accurate, and there is a problem.
Le Mans Master
Joined: Apr 2000
Posts: 5,202
Likes: 10
From: cincinnati ohio
St. Jude Donor '09
Re: Low oil pressure (tshort)
If your oil pressure is acually droping to or near zero, the lifters, and everything else that is controlled by oil pressure is going to start makin' a lot of noise :smash: I would first hook up a known good mechanical guage and take it from there :cheers: Rings have no effect on oil pressure
[Modified by yellow 72, 7:41 PM 5/13/2002]
[Modified by yellow 72, 7:41 PM 5/13/2002]
Race Director
Joined: Aug 1999
Posts: 11,114
Likes: 669
From: SE Pennsylvania
St. Jude Donor '03 thru '26
Oldtimer
Re: Low oil pressure (tshort)
I agree with Yellow72, I'd check the gauge cause it would be tapping like crazy if the oil pressure was dropping to zero at times. Plus the engine would have to be pretty bad shape to have no oil pressure. When you start the engine, does it give out with a chorus of bearing noises? It would if it had been run for any length with zero oil pressure.
Thread Starter
Melting Slicks
Joined: Nov 2001
Posts: 2,659
Likes: 7
From: Katy (Houston) TX
CI 7-8 Veteran
Re: Low oil pressure (killain)
No funny bearing noises at start up. That's the funny thing, at start up it sounds real solid and strong. But after a good run on the highway there is a lot of ticking and definite loss of power. But the loss is only for a short time. Once it cools a little and I'm just cruising at 30-50 mph the ticking seems to fade away and power comes back. The guy I bought it from told me it had solid lifters (which might explain the ticking) but I don't completely trust the things he told me anymore.
It doesn't ever really RUN at zero pressure. It will drop to zero for a very brief moment but then come back.
It doesn't ever really RUN at zero pressure. It will drop to zero for a very brief moment but then come back.
Advanced
Joined: Feb 2001
Posts: 84
Likes: 0
From: hanson ma
Re: Low oil pressure (tshort)
I had the same problem until this weekend. Good pressure on start up but minimal after warm up. Excessive main and rod bearing clearances. Swapped in a new crankshaft. Now have 70lbs at start up and 45 lbs when warm. Good luck.
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Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Re: Low oil pressure (tshort)
Wanted to run this buy you guys/gals and see if you can tell me what the problem is. After just starting engine (or when it hasn't gotten too hot) the oil pressure seems to be just fine (middle of the gauge). But when it gets a litte hotter or when I've been on the highway for a few minutes the oil pressure drops to nearly 0 on hard acceleration and at idle.
I was thinking maybe rings???
I was thinking maybe rings???
:cheers:
Olivier
Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Re: Low oil pressure (tshort)
Wanted to run this buy you guys/gals and see if you can tell me what the problem is. After just starting engine (or when it hasn't gotten too hot) the oil pressure seems to be just fine (middle of the gauge). But when it gets a litte hotter or when I've been on the highway for a few minutes the oil pressure drops to nearly 0 on hard acceleration and at idle.
I was thinking maybe rings???
I was thinking maybe rings???
:cheers:
Olivier
Thread Starter
Melting Slicks
Joined: Nov 2001
Posts: 2,659
Likes: 7
From: Katy (Houston) TX
CI 7-8 Veteran
Re: Low oil pressure (drives61)
Yeah, I've been using 5w-50 and I think I'll switch to 20w-50. Also, when it is full of oil, the pressure is a lot better. But as soon as it is about 1/2 to 1 quart low is when the pressure really drops off. I just put some more oil in it and the pressure is a little more constant at around 35psi.
Burning Brakes
Joined: Dec 2000
Posts: 795
Likes: 0
From: Madison MS
Re: Low oil pressure (tshort)
I agree with the above posts.....excessive bearing clearances. I had the same problem. My engine has over 100k miles on the bearings and it would run 35-40 lbs cold but once warm, the pressure would drop to almost nothing. I tried running a little heavier oil, and that worked, but only marginally. I pulled the pan and replaced the oil pump with a high volume pump under the assumption that if I pumped more oil to the top of the engine, the pressure would in turn go up. It worked. I now have 60lbs cold and never less than 40 lbs with 10w40 oil. The pump swap was a 1 day job. Wouldn't have taken that long but I replaced the timing cover gasket and the front and rear main seals.
Hope this helps.
dl
Hope this helps.
dl
Thread Starter
Melting Slicks
Joined: Nov 2001
Posts: 2,659
Likes: 7
From: Katy (Houston) TX
CI 7-8 Veteran
Re: Low oil pressure (dladd74roadster)
As usual, thanks a bunch for the help. I've been considering putting in a 383 stroker kit and this makes me want to do it even more. Guess when I've got the money saved up I'll go thru with it.
Le Mans Master
Joined: Jul 2001
Posts: 9,622
Likes: 16
From: absecon nj
Re: Low oil pressure (drives61)
i agree with drives61 sounds like the pick up fell off especially when you accelerate and you said it does it more when your a 1/2 quart to 1 quart low.Id check it now to be sure while your at through a new pump in and check th bearings while you got the pan off.
Race Director
Joined: Oct 2000
Posts: 14,994
Likes: 79
From: central FL, near the beach.
Re: Low oil pressure (virtue4u)
I WORKED at NADA. We had a great test. Sit in car with door wide open. Nail it for 1 second, listen for knocks. Repeat. No knocks, car passes test.
