oil pressure still acting funny...
09-15-2012, 12:01 AM
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oil pressure still acting funny... About a month ago my oil pressure was fluctuating badly, and over 3500 rpm the pressure would fall off. First I put a manual oil press gauge on it and it did the same thing. So I dropped the pan and pulled the oil pump and had my dad(machinist/engine builder) inspect everything and the only thing he could find was the check valve in the oil pump seemed to be hanging up a little bit. So we put a new pump in it. Now it seems to be doing the same thing. When you slowly rev it up the pressure stays at 40 until its hits 3500rpm and then drops to 30 and then will slowly climb back up. I noticed that the oil press gauge line has air in it, is that normal? Could something be messed up with the oil port my gauge is connected to?
09-15-2012, 03:22 AM
#4
I'm with 93 vette on that one. With my meldon that thing really moves the oil also. I run extra quart in mine also. I have stock pan. When I put my aftermarket K member in I'm going with bigger oil pan also.
09-15-2012, 09:20 AM
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The pump is a HV and im running a 7qt pan with 7 qts of oil in it. Already changed the oil filter, its a mobil 1. And Im not running a windage tray. Ive been running this exact same setup for several years and it just now doing this.
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09-15-2012, 10:48 AM
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Well, when it did it the first time I changed the pump and while I had the pan off I said screw it and put my 24x conversion on it. I took it to the tuner and told them to watch the oil pressure, and they said it was fine the whole time on the dyno. Then I get it back home and I notice it doing it again. Its got me baffled as to what it is. Thats why I wonder if it has anything to do with the oil port that the gauge taps into?
09-22-2012, 01:52 PM
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Did you ever figure out your problem? Did you ever change the oil filter? I had a similar problem, and it ended up being a collapsed AC Delco oil filter. Now, I run nothing but KN oil filters.
09-22-2012, 02:12 PM
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It was doing this with a ac delco a while back then I switched to a Mobil 1 and did the same thing. so now I switched back to a ac delco and put a thicker oil it and the problem went away, I dont know if it fixed it or the thicker oil just masked the problem. But I haven't lost oil press since I did that.
09-22-2012, 02:16 PM
#16
Has the oil pump drive been inspected? The HV pumps tend to be hard on it.
On the dyno the car was probably a couple inches high in the rear from being on the rollers, as opposed to level on the ground or nose up accelerating.
Few years back I had some pressure issues at high rpm and I think it ended up being my slightly uphill curved street test spot. I put a different windage tray and a pan baffle in. The pan baffle I did because it was an extra $5 and I figured I was going to do all I could while I was there. This was a stock pan and all. I think the "issue" was the curve/incline of where I was testing combined with taking the stock oiling to near 7000rpm which is way beyond what GM designed it for.
HV pumps tend to have cavitation and such issues at higher rpm but since you say it starts at 3500 I don't think it is that yet.
Edit,
A HV pump and thicker oil is begging for oilpump drive issues.
On the dyno the car was probably a couple inches high in the rear from being on the rollers, as opposed to level on the ground or nose up accelerating.
Few years back I had some pressure issues at high rpm and I think it ended up being my slightly uphill curved street test spot. I put a different windage tray and a pan baffle in. The pan baffle I did because it was an extra $5 and I figured I was going to do all I could while I was there. This was a stock pan and all. I think the "issue" was the curve/incline of where I was testing combined with taking the stock oiling to near 7000rpm which is way beyond what GM designed it for.
HV pumps tend to have cavitation and such issues at higher rpm but since you say it starts at 3500 I don't think it is that yet.
Edit,
A HV pump and thicker oil is begging for oilpump drive issues.
09-22-2012, 02:23 PM
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Has the oil pump drive been inspected? The HV pumps tend to be hard on it.
On the dyno the car was probably a couple inches high in the rear from being on the rollers, as opposed to level on the ground or nose up accelerating.
Few years back I had some pressure issues at high rpm and I think it ended up being my slightly uphill curved street test spot. I put a different windage tray and a pan baffle in. The pan baffle I did because it was an extra $5 and I figured I was going to do all I could while I was there. This was a stock pan and all. I think the "issue" was the curve/incline of where I was testing combined with taking the stock oiling to near 7000rpm which is way beyond what GM designed it for.
HV pumps tend to have cavitation and such issues at higher rpm but since you say it starts at 3500 I don't think it is that yet.
Edit,
A HV pump and thicker oil is begging for oilpump drive issues.
On the dyno the car was probably a couple inches high in the rear from being on the rollers, as opposed to level on the ground or nose up accelerating.
Few years back I had some pressure issues at high rpm and I think it ended up being my slightly uphill curved street test spot. I put a different windage tray and a pan baffle in. The pan baffle I did because it was an extra $5 and I figured I was going to do all I could while I was there. This was a stock pan and all. I think the "issue" was the curve/incline of where I was testing combined with taking the stock oiling to near 7000rpm which is way beyond what GM designed it for.
HV pumps tend to have cavitation and such issues at higher rpm but since you say it starts at 3500 I don't think it is that yet.
Edit,
A HV pump and thicker oil is begging for oilpump drive issues.
09-22-2012, 02:36 PM
#18
What weight oil are you using now? The factory oil cooler is known to be a restriction although the black Moroso manufactured one is better in this regard than the later one. I took my oil cooler off and use a 1060 Napa Gold (Wix) filter. Wix makes a nice filter.
09-23-2012, 08:49 AM
#19
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You can't see the oil pump drive gear when you change the pump. Do you mean you removed the intake manifold and inspected the gear, too? Why do you need an HV pump, anyway?
09-25-2012, 08:18 PM
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He said the drive, so I thought he was talking about the rod going down to the pump. But I know for sure its not the drive now because the thicker oil would have made it worse if that was the case. Im running the HV pump because thats what my dad puts in all his engines and has never had a problem. Ive never had any issues with oil the past 3 years up until now for some reason, but the engine will be coming out this winter to find out whats really going wrong.