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#1
12-26-2003, 10:48 AM
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I've got a 400 Pontiac W/E heads. Problem is I was carring 80 psi +/- 10 psi for the last 2 years. Now @ idle I'm barely making 10 psi.
 What went wrong? Car still runs great. I've changed oil, and other basic checks. I'm afraid it's time to go in the motor. Were do I go first? What to look for & would I be better off looking for a 455? Does anyone have a 455 they want to get rid of?
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#2
12-26-2003, 10:48 AM
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I've got a 400 Pontiac W/E heads. Problem is I was carring 80 psi +/- 10 psi for the last 2 years. Now @ idle I'm barely making 10 psi.
What went wrong? Car still runs great. I've changed oil, and other basic checks. I'm afraid it's time to go in the motor. Were do I go first? What to look for & would I be better off looking for a 455? Does anyone have a 455 they want to get rid of?
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#3
12-26-2003, 11:08 AM
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Sounds like you have an internal oil pressure leak. There are ways for the pros to check but the best way for you is to drop the pan and visually check the bearings.
As for 455 vs 400 its all a matter of choice. If you have to buy a 455 to rebuild it might be cheaper to go through your own engine. Good luck. |
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#4
12-26-2003, 11:08 AM
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Sounds like you have an internal oil pressure leak. There are ways for the pros to check but the best way for you is to drop the pan and visually check the bearings.
As for 455 vs 400 its all a matter of choice. If you have to buy a 455 to rebuild it might be cheaper to go through your own engine. Good luck. |
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#5
12-26-2003, 11:09 AM
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Sounds like you have an internal oil pressure leak. There are ways for the pros to check but the best way for you is to drop the pan and visually check the bearings.
As for 455 vs 400 its all a matter of choice. If you have to buy a 455 to rebuild it might be cheaper to go through your own engine. Good luck. |
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#6
12-26-2003, 11:11 AM
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LOOKS LIKE MY COMPUTER PULLED A BOO-BOO. It couldn't been my fault.
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#7
12-26-2003, 11:32 AM
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Are you sure the gauge is good? Have you checked pressure with a known good gauge?
__________________
George Hill '63 Star Chief, '95 Chevy P/U, lots of BMW motorcycles and cars |
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#8
12-26-2003, 01:38 PM
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I would do another oil change with a different brand filter.I Had the same thing happen to me.I was using a penzoil filter,went to the ac delco and oil psi came back up to normal.I think the filter was bypassing or defective,
The thick CLOUD of tire smoke ,the SMELL of burning rubber,and the CHEER of the crowd ....PRICELESS. $90.00 fine for an awesome burn-out,worth every penny http://www.theyman.com
__________________
The thick CLOUD of tire smoke ,the SMELL of burning rubber,and the CHEER of the crowd ....PRICELESS. $90.00 fine for an awesome burn-out,worth every penny... http://www.youtube.com/watch?v=iI7beXh7xW8 |
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#9
12-26-2003, 05:44 PM
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I haven't changed gauges yet. The reason why is because the gauge will read up to 100 psi w/30 weight oil. My instincts tell me to tear down. As far as oil filters I went from an ac/delco to a fram with no change.
I'm to the point of go tell she blows. Then I'll know what was wrong.
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#10
12-26-2003, 06:25 PM
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maybe a oil galley plug popped out of front of motor? possibly crud stuck in under the check ball in the oilpump. Better than a total teardown atleast.
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#11
12-26-2003, 10:02 PM
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Had the same problem in my 428.
Turned out it was the rod bearings going away. Wish I'd checked further then I did. Maybe then my crank, rod, and piston wouldn't have been toasted.
__________________
"Bye" "Bye" Rice Boy!!! |
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#12
12-27-2003, 08:57 PM
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Might be time to go in... If she,s got alot of miles, It,s Time.
--------------------------------------------------------- "GTO? "Get Tools Out!!!" ---------------------------------------------------------  
__________________
--------------------------------------------------------- "And he Asked, Who Owns This Car? With The Peace Sign, Mag Wheels, and the Four on the Floor?? --------------------------------------------------------- |
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#13
12-28-2003, 08:37 AM
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See the engine doesn't have alot of miles. As a matter of fact it's accually pretty fresh. The motor's about 5 years old, but doesn't have 20,000 miles on it. I've had NO problems with it up to this point. This wasn't a slow proccess, the oil pressure just descided to shot crapps. Is there another couple of places to hook up an oil pressure gauge? Just so I can see were the pressure drop is. I have it hooked up on the back side of the oil filter now, is there a better spot.
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#14
12-28-2003, 11:18 AM
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I also had a peice of blue sealer get into the copper line that goes to the gauge. I took the line apart and attempted to blow compresed air through it with no luck. I replaced the line and instant pressure.GOOD LUCK
The thick CLOUD of tire smoke ,the SMELL of burning rubber,and the CHEER of the crowd ....PRICELESS. $90.00 fine for an awesome burn-out,worth every penny http://www.theyman.com
__________________
The thick CLOUD of tire smoke ,the SMELL of burning rubber,and the CHEER of the crowd ....PRICELESS. $90.00 fine for an awesome burn-out,worth every penny... http://www.youtube.com/watch?v=iI7beXh7xW8 |
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#15
12-28-2003, 04:46 PM
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Is ther a guide line for oil pressure? Such as 10 psi per 1000 rpm? If so I still meet that.
So is it safe to wait? I guess what I'm wondering is if the engine is just breaking in and I may be over reacting? That and I've got alot of time and money in this and can't figure out what happened.
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#16
12-28-2003, 05:02 PM
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The best place to pull your oil pressure reading from is the plug on the drivers side of the distributer pad. That gives a true reading of the pressure in the engine. I personally don't like the pressure by-pass in the oil filter housing, nor do I like standard Fram filters, either.
Bill [This message was edited by WDCreech on December 28, 2003 at 07:11 PM.]
__________________
Bill 64 GTO, tube chassis w/606" IA tall deck, PG & a pro geared Fab 9". 2750 lbs. 8.2550@164.17-1/4, 5.2901@131.97-1/8, 1.1981-60-ft. 8/10/08 
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#17
12-28-2003, 08:15 PM
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I don't have a problem changing filters. 10 sec is alot better than a tear down. I'll get a new gauge set up tommorrow and try the spot by the dist. it may not get done tommorrow but I'll get the stuff together. Thanks for the input. I'll get back when I know more. Any thoughts on the 10 psi per 1000 rpm rule?
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#18
12-28-2003, 08:27 PM
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My 428 failed with only 2,000 miles on it.
Also check the oil pump by pass ball. If something get's in there it'll cause the pressure to drop also. Been there done that too. "Bye Bye Rice Boy"
__________________
"Bye" "Bye" Rice Boy!!! |
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#19
12-28-2003, 08:52 PM
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Try a new filter first, AC-Delco or the Fram HP2, don't use the short Fram. You have your pressure gauge connected to the stock location on the oil filter housing, this is the DIRTY oil side before the oil enters the filter and the line or sender whichever you are using may have plugged. Like i said try another filter, i understand that the K/N oil filter is excellent.
Robert Williams
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"Three may keep a secret, if two are dead" ~ Benjamin Franklin ~ |
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#20
12-28-2003, 10:14 PM
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Correct, 10PSI for every 1000RPM is all that is required.
Herb If it ain't broke, don't fix it!
__________________
74 Ventura 462/#13 heads/3350# 10.38 @ 128.89 MPH, N/A, Stock suspension, 275/60 Radial, Street legal, Tagged & Insured |
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