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Discussion Starter #1
My 632 CID pump gas engine has a Melling standard pressure/high volume oil pump. Even when the engine reaches full operating temperature, the oil pressure is at about 32 PSI during idle, and climbs to 79-80 PSI by 2,500 RPM and stays there until the throttle is let off. This is with 10/40W oil. Is that a bad thing? I welcome anyone to comment, but I especially hope to hear from you guys who are professional engine builders.
 

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Your clearances are likely tighter which would bring the pressure up somewhat.
You tried a 10/30W ?
 

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Discussion Starter #4 (Edited)
I'm just a halfast bracket racer, mine is 25psi hot at idle.
No you're not Bob. Not as far as I'm concerned. And your opinion and veiwpoints are very much appreciated. I'm mostly curious about the 80 PSI reading above 2,500 RPM. I suppose that a high reading is better than one that's too low, but I'm wondering if there's anything negative or deterimental about oil pressure being that high. I know that high oil pressures are said to cause more wear and tear on the distributor gear, but I'm wondering if there's any other possible negatives or if it's really anything to worry about.

Gee the function of this webpage is sure giving me trouble today. I dunno if it's just my particualr internet service though. :mad:
 

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Discussion Starter #5
Your clearances are likely tighter which would bring the pressure up somewhat.
You tried a 10/30W ?
I haven't tried 10W30 oil, only cuz the engine manufacture (World) recommends 10/40 & 20/50 oils to be used. And I know that atleast one other World customer on here claimed that he found the bearing tolerances on his engine to be very loose. But that's all I have to go by, since I cannot say that I checked the tolerances on my own engine before I installed into the car.
 

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I think you're fine. Be happy it holds that good with a std volume pump. I like oil pressure. Makes me feel good!

JIM
 

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I have the HV Melling pump and when hot it idles at 40 with 20/50. So I'd say you're ok.
 

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My 632 CID pump gas engine has a Melling standard pressure/high volume oil pump. Even when the engine reaches full operating temperature, the oil pressure is at about 32 PSI during idle, and climbs to 79-80 PSI by 2,500 RPM and stays there until the throttle is let off. This is with 10/40W oil. Is that a bad thing? I welcome anyone to comment, but I especially hope to hear from you guys who are professional engine builders.
Put some 10W30 in there and try it

If its a Roller use Valvoline Synthetic or Royal Purple
 

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Hi Billy until the big boys chime in I had 40-50 at idle with 15-40w and dropped down to 10w30 and have 30-35 at idle 60-70 on the throttle. It is a HV pump though.
 

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Someone posted this link a while ago and it is a very interesting read. Ever since I read it, I have been using 5w-30 in all my cars and they are running fine.
http://ferrarichat.com/forum/showthread.php?t=136052
I posted this a month a ago. This goes against most common beliefs that thicker is better. But test and science does not agree. Word of mouth says go thicker, but you do not hear many manufactors saying go 40 weight out the gate or its manditory you switch to 40 weight.I even looked at the old chevy books. Now I do take into account the new oils do not having enough zddp, that may have changed but the weights have not. When going with that 40-50 weight, that extra pressure that you believe is coating is nothing but resistance and making your pump work harder. Remember, you want quicker flow, not thicker slower flow. If you get 90-95% of most engine damage and wear at start up. The thicker oils take longer to reach ideal viscoisty than some of your smaller weights. Now thats facts. I tried the 15w-40 Rotella during the ZDDP craze, dumped it after running it a short period of time and went back to 10w-30 with a ZDDP additive. Be careful of viscosity drag with the thicker oils as well. I know this goes against most of what you have been taught for years.:thumbsup:
 

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Someone posted this link a while ago and it is a very interesting read. Ever since I read it, I have been using 5w-30 in all my cars and they are running fine.
http://ferrarichat.com/forum/showthread.php?t=136052
YES YES Excellent read, i have read this many times and it is extremely insightful. :yes:

0W30 is all i am running now, oil pressure is great at idle 25-35 and 70+ @ WOT with a melling HV pump.

I like how the article explains Flow Vs Pressure and the misconceptions that go along with it.
 

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Discussion Starter #17
Thanks guys. I have the melling HV pump. It's a HV pump, but not a hi-pressure one. I've heard that World products uses wide bearing clearances, so maybe that is why they recommend the heavier oils. I dunno. I'll keep in mind what was stated here, but from what I'm hearing, the 80 PSI at higher RPM isn't so much any problem. that's the info I needed. ;)
 

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I got one for you.....

Take a milkshake that is frozen, and suck it through a straw.
Then take the milk shake after sitting about for about 30 minutes and suck it through the straw. You noticed it took more pressure to suck it through the straw in its thicker form than when it was in its slightly less solid properties state. No a milke shake is not oil but, listen to the concept I am conveying.
 

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Discussion Starter #19
I got one for you.....

Take a milkshake that is frozen, and suck it through a straw.
Then take the milk shake after sitting about for about 30 minutes and suck it through the straw. You noticed it took more pressure to suck it through the straw in its thicker form than when it was in its slightly less solid properties state. No a milke shake is not oil but, listen to the concept I am conveying.
No argument there. I wonder about the possibility of foaming or aeration of the oil in engines with longer strokes and more of a potential for windage? I have a windage tray in my oil pan, but with a 4.75" stroke, I'm sure that the crankshaft produces hurricane type conditions in that oil pan during high RPM operation.

So I wonder if the lighter weight oils can or will aerate easier. Aeration of the oil as you know can kill bearings.
 

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Thanks guys. I have the melling HV pump. It's a HV pump, but not a hi-pressure one. I've heard that World products uses wide bearing clearances, so maybe that is why they recommend the heavier oils. I dunno. I'll keep in mind what was stated here, but from what I'm hearing, the 80 PSI at higher RPM isn't so much any problem. that's the info I needed. ;)
=
Billy
Regardless of what you were told you have the Hi pressure spring in there if you have an 80lb bypass
 
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