Pulsing oil pressure.... a bad sign? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Stainless · 06-19-2003, 05:27 PM

Hey all... something i've noticed on my oil pressure. When the engine is warm, and at low rpms (under 1000), the oil pressure pulses. I noticed it when I first bought the engine (olds 455), but now it seems to be getting worse. I don't know for certain when the motor was rebuilt, but there isn't a bit of grit or buildup on the rocker arms/valve covers, so I would guess not too long ago.

Usually, as you increase the rpm's, it smooths out, but now, it seems to be sticking around more.... also, it is fine when the motor is cold.... smooth at all rpms....

any thoughts????

Thanks!!
~Sean

crazy longhorn · 06-19-2003, 05:40 PM

If its not making any funny noises, I would suspect a sticky bypass valve in the oil pump. I have seen that on a BB Olds, that was fresh(that I checked clearances on assembly). The BB Olds is a runner, but the oiling system is the biggest issue to deal with. I ran a Melling hy vol pump, with a Toronado pan/ windage tray, & main restrictors. valve train geometry gets to be fun with the big cams also......but that big Olds will make a 4000 lb truck flat smoke the hides at 100mph pulling high gear on an auto trans.......(you know, I hope it goes straight!) crazyL

Stainless · 06-19-2003, 05:46 PM

No, there are no funny noises.... I suspect it has a high volume pump, it runs over the 3/4 mark on our chevy guages....

is the bypass valve servicable? Or time for a new pump?

might as well put on a chrome pan while I have it off right? chrome makes it faster?

thanks!

~Sean

*racedvl* · 06-19-2003, 06:03 PM

Chrome = Bad.

Let me tell you why.

The big reason is that it doesn't dissapate heat very good. Chrome becomes rusty very easy.
And cheap chrome is hard to seal. (leaks)

Chrome looks nice and all, but unless it's a air filter lid, it will not be under the hood of my truck. I am sometimes known as the ainti-chrome.

crazy longhorn · 06-19-2003, 06:31 PM

2nd that,I dont have much use for chrome!you wont see it under my hood either

The pump i had problems with , was the only one I didnt take apart & clearance,clean ,ect. you might replace it , if you arent sure of the history. The M 22 HV should be the pump to use on the Olds, & will have a bolt on pickup tube. I would check Moroso, or Milodon on the pan(6 or 7 quart should do you). Good luck,crazyL

Longhorn Man · 06-19-2003, 08:41 PM

Also, if your chrome pan has ANY chrome on the inside (some cheap ones do) and your pan smacks the ground, you can have chrome particles floating in your oil.
Not good.

How long has your oil been in there? I have seen oil that needed chainged do this.

Stainless · 06-20-2003, 07:28 AM

I just changed the oil last weekend.... less than 200 miles ago.... the only thing that's changed since the oil change was my oil pressure dropped a little... just a thinner oil I suspect.... (it still had the oil from when I bought the motor)...

~S

06-19-2003, 05:27 PM	#1
Stainless Registered User Join Date: Jan 2003 Location: N.Canton Ohio Posts: 59	Pulsing oil pressure.... a bad sign? Hey all... something i've noticed on my oil pressure. When the engine is warm, and at low rpms (under 1000), the oil pressure pulses. I noticed it when I first bought the engine (olds 455), but now it seems to be getting worse. I don't know for certain when the motor was rebuilt, but there isn't a bit of grit or buildup on the rocker arms/valve covers, so I would guess not too long ago. Usually, as you increase the rpm's, it smooths out, but now, it seems to be sticking around more.... also, it is fine when the motor is cold.... smooth at all rpms.... any thoughts???? Thanks!! ~Sean

06-19-2003, 05:40 PM	#2
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,403	If its not making any funny noises, I would suspect a sticky bypass valve in the oil pump. I have seen that on a BB Olds, that was fresh(that I checked clearances on assembly). The BB Olds is a runner, but the oiling system is the biggest issue to deal with. I ran a Melling hy vol pump, with a Toronado pan/ windage tray, & main restrictors. valve train geometry gets to be fun with the big cams also......but that big Olds will make a 4000 lb truck flat smoke the hides at 100mph pulling high gear on an auto trans.......(you know, I hope it goes straight!) crazyL __________________ 69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears....

06-19-2003, 05:46 PM	#3
Stainless Registered User Join Date: Jan 2003 Location: N.Canton Ohio Posts: 59	No, there are no funny noises.... I suspect it has a high volume pump, it runs over the 3/4 mark on our chevy guages.... is the bypass valve servicable? Or time for a new pump? might as well put on a chrome pan while I have it off right? chrome makes it faster? thanks! ~Sean Last edited by Stainless; 06-19-2003 at 05:49 PM.

06-19-2003, 06:31 PM	#5
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,403	2nd that,I dont have much use for chrome!you wont see it under my hood either The pump i had problems with , was the only one I didnt take apart & clearance,clean ,ect. you might replace it , if you arent sure of the history. The M 22 HV should be the pump to use on the Olds, & will have a bolt on pickup tube. I would check Moroso, or Milodon on the pan(6 or 7 quart should do you). Good luck,crazyL __________________ 69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears....

06-19-2003, 06:03 PM	#4
racedvl Account Suspended Join Date: Jan 2000 Location: Woodstock, IL Posts: 7,020	Chrome = Bad. Let me tell you why. The big reason is that it doesn't dissapate heat very good. Chrome becomes rusty very easy. And cheap chrome is hard to seal. (leaks) Chrome looks nice and all, but unless it's a air filter lid, it will not be under the hood of my truck. I am sometimes known as the ainti-chrome.

06-19-2003, 08:41 PM	#6
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Also, if your chrome pan has ANY chrome on the inside (some cheap ones do) and your pan smacks the ground, you can have chrome particles floating in your oil. Not good. How long has your oil been in there? I have seen oil that needed chainged do this.

06-20-2003, 07:28 AM	#7
Stainless Registered User Join Date: Jan 2003 Location: N.Canton Ohio Posts: 59	I just changed the oil last weekend.... less than 200 miles ago.... the only thing that's changed since the oil change was my oil pressure dropped a little... just a thinner oil I suspect.... (it still had the oil from when I bought the motor)... ~S



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