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Old 07-09-2010, 09:47 PM
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oil pressure

i recently put a crate engine into my 1984 camaro z28. the engine is a 383 stoker from blueprint engines. it was a deluxe style engine so the only thing i needed to put on was the accessories, fuel line, water and oil sending units, spark plugs, wires, etc. when i first started the engine everything was fine. after 2,000 miles is when the thing started acting goofy. i have an electric oil sending unit using auto meter sport comp gauges. at first start up i had steady oil pressure at around 75lbs at cold idle and it would drop to around 50ish when warm. now when i start it, it hits 75, and then it drops to about 10. it doesnt change when i put it in gear and when i drive except when i let off the gas, it spikes at 50 and when i give it gas, it goes right back down to 10. PLEASE someone help me out! i am a little new at this, but i know im not an idiot when it comes to cars.
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Old 07-09-2010, 10:15 PM
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Quote:
Originally Posted by Camaro820
i have an electric oil sending unit using auto meter sport comp gauges. at first start up i had steady oil pressure at around 75lbs at cold idle and it would drop to around 50ish when warm. now when i start it, it hits 75, and then it drops to about 10.
I would immediately plumb a mechanical gage to check the accuracy of the electric unit.
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Old 07-10-2010, 12:19 AM
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i did that too. it was the same except the gauge was reading higher.
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Old 07-10-2010, 12:37 AM
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What brand of oil filter are you using??

Another possibility is that the oil pump pickup has come loose from the pump.
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Old 07-10-2010, 10:54 AM
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the pickup could have very well came loose. i had the wrong harmonic balancer on and the car vibrated badly. and im using a purlator filter.
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Old 07-10-2010, 04:28 PM
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Was the pump pre-installed with the pick up tube?
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Old 07-10-2010, 04:54 PM
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I had the same symptoms once, the pick-uo had broken the bolt-on leg/retainer(race pan pick-up) and came out of the pump, found it laying in the pan at disassembly. Was fine until it was shut off after the drive home from the races, then lack of suction apparently let it fall away from the pump. Start it the next day, good cold pressure for a short bit then very low, 5-10 lbs. Shut it off, give it a few minutes for complete drain back, and it would repeat the scenario when started again.

After verifying the filter was fine came to the conclusion pick-up had somehow come off, wasn't expecting it because of the bolt-on brace....pump will pull oil for a bit as the whole body sits 1/2 way down into the oil at rest, soon as it pumped some up into the galleys the pan would then be too low to feed the pump without the pick-up. Got lucky and it didn't hurt a thing, fixed the pick-up(they get brazed to the pump now!).

I came to the conclusion that the solid motor mounts retain some vibration back into the whole assembly compared to rubber dampened stock type mounts, a friend has since also had the same thing happen with solid mounts in a similar street/strip car. Don't know for sure if I am right, but it makes sense with the facts on hand.

In my case it took 2000 miles for it to break both legs of the pick-up brace bolted to the pump, friends took 4-500 miles or so, his was a stock pick-up with no brace.

Sounds like you are going to have to get in there and take a look.
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Old 07-12-2010, 09:24 PM
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yes, the pump was pre-installed. i did call a local performance shop and i did ask what kind of oil filter i should use and they told me that i should use a high flow oil filter. would that honestly make me have low pressure?
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Old 07-12-2010, 10:23 PM
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We went through a period recently where Fram oil filters and perhaps some other brands would restrict the flow of oil through the filter, but It sounds like you have a different problem. Drop the pan and have a look.
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Old 07-14-2010, 09:35 PM
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dropping the pan is something that i really dont want to do. really not in the mood to lift the engine up. what aggravate me is that this is a brand new engine from people who are supposed to know what they are doing. i called the manufacturer because the engine is still under warranty. they told me that their techs were busy and they would call me back. which of course they didn't and this is the second time this has happened. i also noticed what looks like baked oil coming from the front where the intake meets the head. never touched the bolts to the intake. i am no fool when it comes to engines but i am also no pro. could that have a play in low oil causing a vacuum leak? i am more than half tempted to send the motor back to the company. i seem to be having more problems with this engine than it's worth. what would anybody else do?
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Old 07-14-2010, 09:46 PM
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Quote:
Originally Posted by Camaro820
dropping the pan is something that i really dont want to do. really not in the mood to lift the engine up. what aggravate me is that this is a brand new engine from people who are supposed to know what they are doing. i called the manufacturer because the engine is still under warranty. they told me that their techs were busy and they would call me back. which of course they didn't and this is the second time this has happened. i also noticed what looks like baked oil coming from the front where the intake meets the head. never touched the bolts to the intake. i am no fool when it comes to engines but i am also no pro. could that have a play in low oil causing a vacuum leak? i am more than half tempted to send the motor back to the company. i seem to be having more problems with this engine than it's worth. what would anybody else do?
Start w/a fresh filter. So as to not queer your warranty, I would make them give me a recommendation- in writing, if possible- if this doesn't help.

If you open the engine up, do NOT be surprised if they simply refuse to do anything. You have to be firm on this w/them, this is no time for being an agreeable sort- I'm NOT recommending you be heavy-handed w/them, but in the same light, you've got to be forceful enough to get results.

The squeaky wheel gets the grease- call them twice a day (4x, 10x?)- until they give you some direction.
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Old 07-14-2010, 10:03 PM
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You will have to pull the pan..Read the written warranty closely.. Probably get a statement from a licensed mechanic and take lots of pics. Sounds like a bearing problem.

The commercial re builders I deal with require the above. Also keep track of time. If it goes to court. Many states will re-reimburse you far all expenses..

I have been a professional witness against several rebuild shops. Customer tends to win over a shop.. Biggest problem then is collecting...

Just had one yesterday. A new SBC that had no oil pressure (10 psi). No oil to the lifters.. My shop inspected the engine and the rear cam bearing was not installed correctly. Leaving the annular groove exposed. Nasty internal oil leak..
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Old 07-14-2010, 10:05 PM
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Quote:
Originally Posted by Camaro820
what would anybody else do?
I know this is after the fact and not helpful at this point, but maybe next time you could start with a bare block and build it yourself. That's what I would have done. TRUST NOBODY.
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Old 07-14-2010, 10:08 PM
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What do you mean, "Leaving the annular groove exposed"?
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Old 07-14-2010, 10:29 PM
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Cam bearings in a SBC have an oil groove in the block behind the bearing. This is why the cam bearings in a Chevy can be installed with oil hole in several places. The cam bearing has to be installed with the groove centered on the backside of the bearing.. The rear bearing mount has no set stop and the bearing can be installed too far forward or back. Too far forward leaves the oil groove open, too far back and the rear cam plug hets bearing..
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