oil pressure still acting funny...
09-25-2012, 09:49 PM
#21
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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.
09-26-2012, 07:41 AM
#22
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. ..... 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.
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. ..... 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.
Edit,
A HV pump and thicker oil is begging for oilpump drive issues.
09-26-2012, 11:50 AM
#23
The thicker oil might just mask issues.
If a shop told me they wanted to put a HV pump in a normal NA LT1 build I wouldn't use that shop for anything. They might have a place in a high power forced induction/spray setup with loose tolerances to be more forgiving as everything flexes and moves but on a normal street NA setup all they will do is create issues. They go into bypass earlier and at high rpm don't push any more oil through the bearings due to bypass so all it does then is heat the oil, place needless load on the drive and increase the likelyhood of cavitation.
If a shop told me they wanted to put a HV pump in a normal NA LT1 build I wouldn't use that shop for anything. They might have a place in a high power forced induction/spray setup with loose tolerances to be more forgiving as everything flexes and moves but on a normal street NA setup all they will do is create issues. They go into bypass earlier and at high rpm don't push any more oil through the bearings due to bypass so all it does then is heat the oil, place needless load on the drive and increase the likelyhood of cavitation.
09-26-2012, 08:47 PM
#24
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The thicker oil might just mask issues.
If a shop told me they wanted to put a HV pump in a normal NA LT1 build I wouldn't use that shop for anything. They might have a place in a high power forced induction/spray setup with loose tolerances to be more forgiving as everything flexes and moves but on a normal street NA setup all they will do is create issues. They go into bypass earlier and at high rpm don't push any more oil through the bearings due to bypass so all it does then is heat the oil, place needless load on the drive and increase the likelyhood of cavitation.
If a shop told me they wanted to put a HV pump in a normal NA LT1 build I wouldn't use that shop for anything. They might have a place in a high power forced induction/spray setup with loose tolerances to be more forgiving as everything flexes and moves but on a normal street NA setup all they will do is create issues. They go into bypass earlier and at high rpm don't push any more oil through the bearings due to bypass so all it does then is heat the oil, place needless load on the drive and increase the likelyhood of cavitation.
The pump has worked perfect for three years, "NEVER" had a problem until recently.
09-27-2012, 07:50 AM
#26
The normal NA mediocre engine with a 2-300 shot is not really that much power. If you are going to try and play at that level though you need to be accepting of possible compromises like say the HV pump eating the drive gear.
It is well documented that the HV pump does that, and for every guy who swears he needs a HV pump there is another making more power on a standard volume without the issues the HV creates.
If you want to treat your LT1 like it is a 70s engine then maybe have Daddy port some 202 fuelie heads for it a 3/4 racecam and then top it with a Holley double pumper.
It is well documented that the HV pump does that, and for every guy who swears he needs a HV pump there is another making more power on a standard volume without the issues the HV creates.
If you want to treat your LT1 like it is a 70s engine then maybe have Daddy port some 202 fuelie heads for it a 3/4 racecam and then top it with a Holley double pumper.
09-27-2012, 08:10 AM
#27
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Your killing me dude, what ive been saying is that I haven't had a problem with the HV pump for several years. I put a new pump in and still did the same thing, put ticker oil in it and it went away. Which means its not the drive gear because the thicker oil would make it worse if it was, right?
09-27-2012, 10:11 PM
#29
I lost oil pressure Completely. My oil pressure guage would do alittle dance like how you describe around 4-5k the pressure would dip down and then raise up. Much more serious then first thought of. 
10-02-2012, 05:22 PM
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Since I have the time and because I have never seen it mentioned on Tech, I’ll go for the long winded explanation along with a real life example. The PCV system: PCV stands for positive crankcase ventilation; this is a controlled vent for the crankcase. At idle or times of high manifold vacuum the PCV valve is normally closed. Manifold vacuum pulls a ball or “valve” against spring pressure to seal an orifice. In its closed state, manifold vacuum is sealed from the crankcase. The pumping action from the bottom side of the pistons at idle creates little pressure in the crankcase, that small amount of pressure is acting upon the oil in the pan. The oil pump is creating a low pressure which allows the oil to travel up the pick up tube. This is a recipe for good oil pressure @ idle and low speed driving. Now, the Situation rolls up on you in his 5.0….WOT ensures a good fight. WOT or wide open throttle severely drops the vacuum available in the intake manifold(though there is still low pressure), the spring in the PCV valve pushes the ball off its seat and allows the building crankcase pressure to vent into the manifold where the oil vapors can be combusted. Since there is still no measureable amount of vacuum in the crankcase the oil pump can easily draw the oil into the pick up tube. Now imagine if the PCV valve was to stick. If it was stuck closed the crankcase pressure would build, assuming you did not alter the PCV system by adding a valve cover breather; that pressure will be looking for a way out and it will find it either threw a seal or gasket; oil leaks? You’ll have them. As a side effect your oil pressure will rise by a small amount. What if the PCV sticks open? At idle and times of high manifold vacuum the crankcase will also see that vacuum. This can cause trouble if the conditions are just right, such as low pumping pressure from a low idle speed, low oil pressure at low rpm by design, or even a high volume oil pump. What happens is there is now competing vacuum sources on the oil sitting in the pan. Now if you got a radical bumpstick that has poor vacuum at idle you may never see an issue, but if you have good manifold vacuum that is active in the crankcase oil pressure will drop. Up until a few years ago I would never have believed this was possible without a vacuum pump (crankcase evacuation pump), but, and you probably guessed by now, here comes my real life example:
Back in 09 a guy at work had been doing a new car prep on a 2010 Town & Country minivan, most guys will let them sit idle in their bay while doing the prep to let the stickers and oils on the exhaust system burn off before delivery to the customer. After about ten minutes of idling this minivan started to squeal like a pig, as he poked around he could not identify the source of the sound. He reached through the window to shut it off and noticed that the oil pressure light was on. He then replaced the oil pressure switch, no change, so he doubled checked it with a manual gauge (BTW these motors have low oil pressure at idle by design, spec 6-10psi hot) and after ten minutes the oil pressure dropped to zero. Being he was a parts changer like most dealer techs he ordered an oil pump and pick up, performed the operation and viola same exact results. He then proceeded to call the engineering hotline, they told him the noise he was hearing was most likely a cam bearing wiping out or spinning and causing the loss of oil pressure. Sure enough it had a spun cam bearing and damaged the block. He got the OK to replace the shortblock(complete rotating assembly with oil pump factory assembled). Upon reassembly he decided to use a thicker oil; 10w30 instead of 5w20. Everything went smooth, fired it up and let it run while he cleaned up, then proceeded to hop in the drivers seat to pull the car out to the lot when I hear the loudest WTF ever. Yup, the oil pressure warning lamp was on again! Mgmt. decided to let someone else take over and since he worked next to me and I was familiar with the work that had been done guess who the lucky fella was… So the next morning I’m handed the RO, I started it and let it run for 15 minutes, humm no light, I go for a nice long test drive, no light. I parked it in my bay and let it sit idle, after about 8 minutes the light pops on. The first thing I noticed was that the weight of the oil changed the timing of the event and as it got hot it happened faster. The more I thought about I realized there was nothing left that was the same in the oil system, so I started to look at things that had not changed, heads and intake. I pulled the valve covers to make sure the drain passages were not blocked, nope their fine. The only thing left that had anything to do with the bottom end was the PCV system. I started the engine and let it run until the oil pressure dropped, then I pulled the PCV hose off…AH-HA, found it, the oil light went off and pressure returned to normal. I pulled the PCV valve from the valve cover and had a look-see, turns out there was a spring in there but no ball…a manufacturing whoopsie.
In the original post he mentioned that slowly raising the RPM he saw a fluctuation, high crankcase vacuum and a HV oil pump could cause this to happen.
To the OP if you are certain the gear is in good condition pull the PCV hose at the throttle body and see if the symptoms change.
Back in 09 a guy at work had been doing a new car prep on a 2010 Town & Country minivan, most guys will let them sit idle in their bay while doing the prep to let the stickers and oils on the exhaust system burn off before delivery to the customer. After about ten minutes of idling this minivan started to squeal like a pig, as he poked around he could not identify the source of the sound. He reached through the window to shut it off and noticed that the oil pressure light was on. He then replaced the oil pressure switch, no change, so he doubled checked it with a manual gauge (BTW these motors have low oil pressure at idle by design, spec 6-10psi hot) and after ten minutes the oil pressure dropped to zero. Being he was a parts changer like most dealer techs he ordered an oil pump and pick up, performed the operation and viola same exact results. He then proceeded to call the engineering hotline, they told him the noise he was hearing was most likely a cam bearing wiping out or spinning and causing the loss of oil pressure. Sure enough it had a spun cam bearing and damaged the block. He got the OK to replace the shortblock(complete rotating assembly with oil pump factory assembled). Upon reassembly he decided to use a thicker oil; 10w30 instead of 5w20. Everything went smooth, fired it up and let it run while he cleaned up, then proceeded to hop in the drivers seat to pull the car out to the lot when I hear the loudest WTF ever. Yup, the oil pressure warning lamp was on again! Mgmt. decided to let someone else take over and since he worked next to me and I was familiar with the work that had been done guess who the lucky fella was… So the next morning I’m handed the RO, I started it and let it run for 15 minutes, humm no light, I go for a nice long test drive, no light. I parked it in my bay and let it sit idle, after about 8 minutes the light pops on. The first thing I noticed was that the weight of the oil changed the timing of the event and as it got hot it happened faster. The more I thought about I realized there was nothing left that was the same in the oil system, so I started to look at things that had not changed, heads and intake. I pulled the valve covers to make sure the drain passages were not blocked, nope their fine. The only thing left that had anything to do with the bottom end was the PCV system. I started the engine and let it run until the oil pressure dropped, then I pulled the PCV hose off…AH-HA, found it, the oil light went off and pressure returned to normal. I pulled the PCV valve from the valve cover and had a look-see, turns out there was a spring in there but no ball…a manufacturing whoopsie.
In the original post he mentioned that slowly raising the RPM he saw a fluctuation, high crankcase vacuum and a HV oil pump could cause this to happen.
To the OP if you are certain the gear is in good condition pull the PCV hose at the throttle body and see if the symptoms change.
