BBC oil pressure loss - Team Camaro Tech
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post #1 of 5 (permalink) Old Aug 29th, 08, 10:12 AM Thread Starter
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Kevin
 
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BBC oil pressure loss

Hey I wanted to check if anyone has had a similar problem before I tear into this early 454. The oil pressure drops around 50 MPH (no tach, must be around 3000 RPM.) If I slow down just a bit, it recovers and is fine once I find the speed it likes. I get around 45 psi until it drops. It seems worse under load. The engine is in my '73 4x4 GMC. It has a big truck pan, about 9 quarts total.

I thought about the oil pump filling up the valve covers and drainback not keeping up with it at speed, but that's a lot of oil in the top end! Dad says it could be the spring in the pump, I am also thinking pickup problem. I know the pickup is not welded to the pump. Anyone have anything similar happen to their rat motor?

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'69 X44, stock 350 (for now), TH350, 3.70:1 gear 8.5" 10 bolt, Auburn Posi.
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post #2 of 5 (permalink) Old Aug 29th, 08, 10:37 AM
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Laurence
 
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Re: BBC oil pressure loss

This might be of some interest...:
http://speedtalk.com/forum/viewtopic...t=oil+pressure

I have a similar issue I need to look into with my engine builder...and mine is a new build! Does the pressure drop right down or just dip 5-10 psi and come back up when you get off the go pedal?

..."you can never go fast enough"..driver,Two Lane Blacktop.
_____________________________________________
68 coupe/475ci/TH400/3.55 rear/Mark Jones motor: 850 Holley DP/Weiand stealth/9.2 comp/ Isky 280 mega cam/ 570+ hp/ 580+ Tq/brutal power!
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post #3 of 5 (permalink) Old Aug 29th, 08, 11:24 AM
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Dave M
 
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Re: BBC oil pressure loss

My guess is that you have a little too much oil in the pan and the crank is beating it into a foam. I've had the same problem on more than one BB in my time. Use caution but you can try running it one quart low and see if the problem goes away.

Dave Miller


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post #4 of 5 (permalink) Old Aug 29th, 08, 11:34 AM
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WES
 
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Re: BBC oil pressure loss

I had a 1969 had the same problem. Drained the oil put a flexable magnet in pan and found the pick up in the bottom of pan. All my p/u get tigged fron now on. WES
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post #5 of 5 (permalink) Old Aug 29th, 08, 12:23 PM Thread Starter
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Kevin
 
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Re: BBC oil pressure loss

Quote:
Originally Posted by Lol_uk View Post
Does the pressure drop right down or just dip 5-10 psi and come back up when you get off the go pedal?
It keeps dropping gradually until I slow down. It doesn't stop dropping if I keep going.

Quote:
Originally Posted by WES 1967 yenko clone View Post
I had a 1969 had the same problem. Drained the oil put a flexable magnet in pan and found the pick up in the bottom of pan. All my p/u get tigged fron now on. WES
That's what I'm thinking, a welder wasn't handy when I put this engine together.

Autosmiths, LLC
'69 X44, stock 350 (for now), TH350, 3.70:1 gear 8.5" 10 bolt, Auburn Posi.
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