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#1
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Oil pressure question
Does anybody have an idea of how much oil pressure to expect from a 440 with full groove mains? I have the high volume pump from Summit and crank is cut .010. Motor is relatively fresh with only just over 5K miles but used to carry about 20lbs at idle but lately has dropped to zero when hot at idle. If you bring the revs up a little like 1K you get 20lbs. On the highway at 3K it makes 40lbs. Maybe this motor is just breaking in? Seems like it should be making more pressure but this is the first time I used the full groove bearings so I'm not sure.
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#2
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Assuming
The clearances are correct, I'd say you need a better pump. My 10 under crank, Clevite bearinged 365 holds 20 at hot idle, and maxes out at 60 hot while driving. My pump is a high volume Melling.
I hope you are not using a Fram oil filter! |
#3
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What oil filter are you running? If it's a fram I would change that first to a Wix, Napa, or Purolator. The filter can cause low oil pressure just like you described. If that doesn't fix it or your already using that filter then you should check your bearing clearences, oil pump clearences, and relief valve.
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#4
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oil pressure
The Fram is what I am using. I will jetison that. The car was carring 20lbs at idle and 60 on the highway but then something changed. I do race the car a little but I don't even use slicks so I can't see how the motor can be hurt. I will get rid of the filter first. Funny thing is all this started after I changed the oil to synthetics. OK first the filter then a new pump if needed. Thanks for the info guys.
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#5
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up the idle to 1200
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#6
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Oh if you changed the oil to synthetics, then the drop in pressure is to be expected at idle.. However if you are using full grooved bearings, you probably could use a bigger pump, which is absolutely a cakewalk on a 440, since it is an external pump... but if you have 20lbs (when hot) at 1000rpm, then that is fine, and about where the idle needs to be set anyways...
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#7
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synthetics should only drop oil pressure 5 psi max from my experience.
also on BB Mopars, I thought all you had to do was change the oil pump discharge spring, which regulates pressure? |
#8
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#9
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yeah but with the springs and making it high pressure can actually hurt an engine, there's a difference between high volume and high pressure, for a street or drag engine you really don't want a high pressure, my dad made the misconception once, and screwed his engine up by using a high pressure way back when on the first engine he ever built way back when he was a wee little child lol... hp pumps use to be more of a dirtrack thing, and i don't even see them as much in dirtrack around here anymore, plus with a high volume there's more to it than just spring pressures it has alot to do with the i guess you call it ports? and the i guess you call it the impeller? it's like a high volume fuelpump compared to a regular pump, or a high pressure pump there's more to it than that..
i would try changing the filter, and go back with conventional oil, i'd go with a high-zinc oil such as valvoline or amsoil especially if it's a flat tappet cam... or at least add either comp cams or lucas engine break-in zinc additive. |
#10
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If I was having issues with low oil pressure, like zero at low idle, I'd keep the synthetic, as it may be the only thing saving your engine.
On a built 440, I bent a pushrod and burped a lifter. I estimate I went 2 to 3 miles with no oil pressure, until I realized it. All I had was oil out of the lifter bore splashing on the crank! If I hadn't been running synthetic, may not have survived! |
#11
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Quote:
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#12
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when i was talking about putting synthetic in my engine everybody here said don't do it... but i'd still run a zinc additive with the synthetic oil if i had a flat tappet cam especially.
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#13
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It flows much faster at startup, and it plain lubricates better, plus, it can handle loss of oil pressure situations much better. I think regular oil breaks down around 400 degrees, while synthetic can make it to 700 degrees.
Synthetics in your engine, tranny, and rearend can take .2 seconds off a quarter mile time! |
#14
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u foreal?? hows that?? i know that royal purple claims using their synthetic oil gives you a little more hp because of less friction in the rotating assembly/ less weight on it, what does it do to the rest of it?? also correct me if im wrong on the more hp..
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#15
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Quote:
20 rwhp. Because synthetic lubricate so well, as evidenced by components running cooler, you get more power from the engine to the wheels. There's been several articles on it. I'll try to find some. Want another .2 secs off your quarter mile? crack the rear of your hood about two inches up, so the air escapes from you engine bay easier. Otherwise, the front of the car acts like a giant wind break. Old racer trick! |
#16
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It is a flat tappet cam. I didn't get a chance to look at it yesterday but I will loose the fram filter today and let you guys know what happens. Thanks again, Bob
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#17
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yeah, i wouldn't run a fram on a go-cart, there's two filters i use, wix or k&n. wix is really the best for the money, i can get good deals on the k&n filters so that's why i run them every now and then, but if you want a reasonably priced filter go with a wix, puralator pureone is good as well, but wix is king..
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#18
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The more I read the more it sounds like I'm in for a bearing change. You guys like the full grooves or not?
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#19
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Quote:
before trying a high output oil pump? |
#20
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Yes full grooved bearings are great, as long as the tolerances are good, and you have the oil pump to support them...
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#21
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Quote:
To see the difference between mineral-based and synthetic fluids, we enlisted the help of Scott Crouse’s ’65 Mercury Comet. With a hot 347, World Class T5 manual transmission, and 4.11 geared 9-inch rear axle, it’s a rolling torture chamber for vital fluids. First we made a series of runs on the Westech Performance Superflow chassis dyno with 20W50 in the crankcase, Dexron III in the gearbox, and 75W90 gear oil in the TracLoc differential; the result was 408.3 horsepower and 405.1 lb-ft of torque. Then we drained the petro-chemicals and replaced them with man-made hydrocarbons from Royal Purple: 7 quarts of 20W50 synthetic engine oil, 6 quarts of Max ATF, and 2½ quarts of Max Gear 75W90. After a 5-mile jaunt to get everything up to the same temperature as the baseline test, we let it rip. The monitor read 418.4 hp and 411.2 lb-ft of torque, a gain of 10.1 hp and 6.1 lb-ft just by switching to synthetics: an impressive tribute to the reduced coefficient of friction. We’ve seen similar improvements on the engine dyno, and have noted reduced wear through the use of synthetics. They’re a bunch more expensive, but in our opinion, they’re worth it for cars you care about. For your $200 Pinto, stick with the 99-cent stuff. PS I think using 20w-50 probably cost them 5 hp as well!! PSS Want another 10 hp? Lower oil level in your oil pan by 1 quart. Less oil drag on the crank!! |
#22
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Notice they didn't specify that they kept the oil temperatures the same. 10hp is easy to gain on a dyno just by raising oil temperatures.
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#23
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Oh no! I will try the filter this morning. It has the high volume pump from Summit. May be the Melling according to my son. If the filter doesn't help I will look at the pump. I can't believe those bearings opened up with so little miles on them. The berings are definately a last resort but you wouldn't think the pump screwed up already also but I guess its possible.
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#24
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Well a major problem with the Fram filter, is that they get clogged so easily, then let all the oil through the bypass without filtering, which can ruin the bearings... also the symptoms you describe also show the bearing tolerances are loose, because the pump will be much more efficient at 1000 rpm vs 700 rpm, so it would stand to reason that the pressure jumps in that small of a change in rpms, especially if it is a little loose... If you already have a HV pump then changing it probably isn't going to help, though if you just have a high pressure pump, then it probably would...
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#25
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I run the Mopar Perf Hi pump (Black spring) with the Mopar Perf P4529190 oil filter. 80lbs at startup about 35 lbs at warm idle.
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#26
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You got a 904 cu in engine in a Cuda????!!!
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#27
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Ok I changed the filter to a Napa and opened up the pump to make sure it was healthy. It looked like new. I put a 1/16 shim behind the spring just for good measure. Oil pressure is great when cold but as it gets to 150 degrees it starts dropping. At 190 it makes about 5-10 pounds idleing in gear at 1000rpm. Nuts...
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#28
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Quote:
What type oil you running??? Wonder if there is a problem with the pickup?? Maybe get an oil cooler?? |
#29
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Oil is 15-40 Rotella. Its what I have been using till I tried synthetic Castrol 10-30. Thats when all this started although I'm sure it wasn't the oil. I've used synthetics before but not in this motor. Looks like the pan will come off next...
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#30
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Quote:
cudabob, you mean two tenths off quater mile by adding 20rwhp?? anybody know of a synthetic oil thats safer to run in an older engine?? i know amsoil, any other? |
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