Re: Oil Pump Bypass Pressure Spring?
[Re: D_C]
#458101
09/03/09 03:43 AM
09/03/09 03:43 AM
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Joined: Aug 2003
Posts: 12,291
Kent, Wa
340SHORTY
Truck Nut
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Truck Nut
Joined: Aug 2003
Posts: 12,291
Kent, Wa
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what engine?
have you ever seen how thin 5w30 oil is when its hot?
if I lived in Cali, I would be running straight 30wt.oh darn I live in Wa and run 30wt...
Last edited by 340SHORTY; 09/03/09 03:44 AM.
I am truckless..
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Re: Oil Pump Bypass Pressure Spring?
[Re: RapidRobert]
#458103
09/03/09 11:31 AM
09/03/09 11:31 AM
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Joined: Feb 2003
Posts: 12,675
Columbia, CT
moper
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Oil pressure below the max output of any pump is controlled by bearing clearances. You can shim the relief, or replcae the spring, but it only affects the pressure that it bypass from. If the pump by pass is normally 75psi (which is where HV pumps typically are) then if it's only producing 50psi it's not in the bypass mode. So if you have 5psi at idle, you need tighter clearances or heavier oil. Std pumps usually by-pass around 50psi. Hp and HV pumps at 75-80psi.
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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Re: Oil Pump Bypass Pressure Spring?
[Re: moper]
#458104
09/03/09 12:06 PM
09/03/09 12:06 PM
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Joined: Mar 2005
Posts: 1,373
Rancho Cucamonga, CA
D_C
OP
pro stock
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OP
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Joined: Mar 2005
Posts: 1,373
Rancho Cucamonga, CA
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Thanks. Appreciate the replies and information. This is the Factory AMC 304 V8 in my '79 CJ5 Jeep. The oil, when Hot, is very thin, almost water-like. Still, I really like using Synthetic motor oil. I suppose I could switch to 15W50, but at $7/Qt: Quote:
Product Description
Mobil 1 15W-50 is the most advanced performance synthetic engine oil designed to provide the cleaning power, wear protection and performance reserve to keep engines running smooth and clean.
Features and Benefits
Mobil 1 15W-50 is formulated with SuperSyn, an extra high-viscosity synthetic fluid, plus extra anti-wear additive to provide extra protection for severe service applications.
Mobil 1 15W-50 is recommended for high performance vehicles including turbocharged and supercharged engines where a thicker oil film is desired.
Mobil 1 15W-50 is also recommended for older valve train designs that may benefit from a higher level of anti-wear normally not required for newer generation vehicles.
Mobil 1 15W-50 will also provide better anti-wear protection for higher valve spring tensions in certain racing engines.
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Re: Oil Pump Bypass Pressure Spring?
[Re: Dodgem]
#458106
09/03/09 02:28 PM
09/03/09 02:28 PM
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Joined: Mar 2005
Posts: 1,373
Rancho Cucamonga, CA
D_C
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OP
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Joined: Mar 2005
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Rancho Cucamonga, CA
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Yes, I plan to swap the oil out soon. Is there any "commonly available" synthetic motor oil, of heavier weight/viscosity, than 20W50 or single-weight? As for the Rocker-arm shaft possibility, the AMC V8 does not use "Shafts." Instead, pivot-posts and "Bridges" are used between each cylinder Intake/exhaust pair. 
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Re: Oil Pump Bypass Pressure Spring?
[Re: D_C]
#458107
09/03/09 03:40 PM
09/03/09 03:40 PM
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Joined: Jan 2003
Posts: 25,743
Rio Linda, CA
John_Kunkel
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Rio Linda, CA
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Red Line has 60 and 70WT synthetic racing oil.
The INTERNET, the MISinformation superhighway
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Re: Oil Pump Bypass Pressure Spring?
[Re: Dodgem]
#458110
09/03/09 06:03 PM
09/03/09 06:03 PM
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Joined: Mar 2005
Posts: 1,373
Rancho Cucamonga, CA
D_C
OP
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OP
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Joined: Mar 2005
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AMC (American Motors Corporation) AMC was an American automobile company formed by the 1954 merger of Nash-Kelvinator Corporation and Hudson Motor Car Company. At the time, it was the largest corporate merger in U.S. history, valued at US$198 million ($1.44 billion in 2006 dollars). When declining sales and the competitiveness of the United States auto market forced AMC to seek a partner in the late 1970s, the company formed an alliance with France's Renault. This lasted until March 2, 1987, when the Chrysler Corporation bought out AMC.  AMC V8 
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Re: Oil Pump Bypass Pressure Spring?
[Re: D_C]
#458111
09/03/09 09:53 PM
09/03/09 09:53 PM
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Joined: Jan 2005
Posts: 3,699
Newport, Mi
Evil Spirit
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Newport, Mi
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Quote:
Thanks. Appreciate the replies and information.
This is the Factory AMC 304 V8 in my '79 CJ5 Jeep.
The oil, when Hot, is very thin, almost water-like. Still, I really like using Synthetic motor oil.
It's probably not just the thin oil - AMC V8's have a history of low oil pressure from the aluminum pump body growing faster from heat than the steel gears, which opens up the clearences and lets pressure drop. Thick oil will probably help, at the expense of high oil pressure at start-up. 
Free advice and worth every penny...
Factory trained Slinky rewinder.........
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Re: Oil Pump Bypass Pressure Spring?
[Re: moper]
#458112
09/03/09 10:52 PM
09/03/09 10:52 PM
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Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
DaytonaTurbo
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Manitoba, Canada
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Quote:
Oil pressure below the max output of any pump is controlled by bearing clearances. You can shim the relief, or replcae the spring, but it only affects the pressure that it bypass from. If the pump by pass is normally 75psi (which is where HV pumps typically are) then if it's only producing 50psi it's not in the bypass mode. So if you have 5psi at idle, you need tighter clearances or heavier oil. Std pumps usually by-pass around 50psi. Hp and HV pumps at 75-80psi.
 If you're getting 5psi at idle that's got nothing to do with your bypass. However moper, my stock pump and my hv pump both bypassed at around the same pressure(75-80).
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Re: Oil Pump Bypass Pressure Spring?
[Re: D_C]
#458113
09/03/09 11:17 PM
09/03/09 11:17 PM
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Joined: Apr 2008
Posts: 1,285
Pacific NW USA
CompSyn
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Quote:
Thanks. Appreciate the replies and information.
This is the Factory AMC 304 V8 in my '79 CJ5 Jeep.
The oil, when Hot, is very thin, almost water-like. Still, I really like using Synthetic motor oil.
I suppose I could switch to 15W50, but at $7/Qt
Nothing wrong with 30-grade motor oil in a high performance application. As long as your not enderance racing for hours at a time or have really loose bearings, there's no reason to run a 50-grade motor oil.
50-grade motor oils made since in the sixties with the oil technology of that time, but today most oils are much more resistant against thermal break down and sharing effects.
Take advantage of today's technology, and the thinner more robust oils that can take a beating; free up some horsepower at the same time.
On a side note, the Mobil 1 5W-30 is an (SM) rated motor oil so it has low zinc and phosphorus. It's a decent oil if you're running a roller cam. But if your running a flat tappet cam, you may want to look for a higher zinc formula motor oil.
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Re: Oil Pump Bypass Pressure Spring?
[Re: Evil Spirit]
#458114
09/04/09 02:34 AM
09/04/09 02:34 AM
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Joined: Mar 2005
Posts: 1,373
Rancho Cucamonga, CA
D_C
OP
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OP
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Joined: Mar 2005
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Rancho Cucamonga, CA
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Appreciate the latest replies. Quote:
It's probably not just the thin oil - AMC V8's have a history of low oil pressure from the aluminum pump body growing faster from heat than the steel gears, which opens up the clearances and lets pressure drop.
Yes, I have heard about this (AMC engines) in the past. I also read that (at idle) an engine doesn't "need" very much oil pressure. As long as it doesn't drop to and linger around Zero, and climbs with RPM you're usually Ok.
Typically, it sinks to around 10-PSI, but the longer at idle and hotter it is (ambient) it can dip down to 5 PSI. Also, the lifters get a bit noisier.
The Oil-Pump is only around a year old. The box it came in indicated it was the High-Performance, High-Volume version, but typically, the Highest pressure I see is around 45-PSI (summertime.)
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Re: Oil Pump Bypass Pressure Spring?
[Re: D_C]
#458115
09/04/09 07:35 AM
09/04/09 07:35 AM
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Joined: Feb 2003
Posts: 12,675
Columbia, CT
moper
I Live Here
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I Live Here
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Posts: 12,675
Columbia, CT
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Im not an AMC guru...lol. But I know the brands with the oil pump in timing covers do have issues on a regular basis. Some of the noises you're hearing are because the engine was never designed to run what you want to, plus there wear that a rebuild doesnt help, like lifter bores and the clearances of the oil pump housing. So if you want to run thin oil, I think it has the protection the engine needs... but it might "just be noisey".
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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