New 440 build oil pressure
- Thread starter Sonny
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Me personally - I would be a bit concerned about this. I don't like to see less than 20 at idle with a hot engine. For me, I would step up to 15W-40 Diesel Oil to see if that raises it any. I agree the shimming the oil pump relief spring would only affect max pressure relief and do nothing for below that. Even my old, stock 64 383 back in the 60s ran at least 20-25 at idle and about 45-50 going down the road. Idle at 12 and 35 at 40 mph may be enough to avoid any engine issues but it strikes me as being unusual for a 383/440.
Sonny
It’s all fun til the rabbit gets the gun.
Any harm in going to a high vol pump? What concerns me is I live in Florida and getting low pressure at 50 degrees outside and engine temps at 170. How low will it go when it’s 95 outside and engine is 190.
On second thought, maybe I’ll bump up to 15-40 oil in the spring. I just need to get comfortable with it
On second thought, maybe I’ll bump up to 15-40 oil in the spring. I just need to get comfortable with it
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A pressure reading is nothing but resistance to flow. The pump will produce a given volume. Internally there are many leak paths in the motor. If the pump has enough volume to overcome the leaks then we have pressure. Lower rpm produces less volume. The relief spring can only raise pressure if the pump produces enough volume. Thicker oil only increases resistance, slowing flow. Bearings and other internal components need flow to keep parts cool. These parts also need a hydro-dynamic wedge of oil to keep the parts from rubbing on each other. Hotter environments require a thicker oil. At a given operating temperature you are still looking for the same basic flow rate. Its simply a function of oil temperature vs oil viscosity. Oil that is to thin will flow out from between the components to quickly, possibly compromising the hydro-dynamic wedge. This all being said. Assuming the internal clearances are with in spec for the type of build. Assuming the oil is at proper running temperature for your climate. If pressure is low, pump volume needs to be increased. Very possible the lifter bores are sloppy causing excessive leak paths. Thus low oil pressure. If oil temp is within reason, which at this time of year shouldn't be an issue. Thicker oil is not the answer. 5w30 is fine. Unless you are going to hammer on it your pressure should suffice. Also to mention not all gauges are accurate. I had a Stewert Warner that read 30psi which was in reality 60psi.
Doug
Doug
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BSB67
Well-Known Member
No harm. But if it was mine, I would put some effort into understanding why. I would start with double verifying the correctness and accuracy of your gauge, then, 2) pull the current relief valve, or entire pump and verify that the valve is not hung-up and is operating smoothly. 3) contact the builder and get the bearing clearances.
Do you know if it has a new Melling pump, or the factory original pump? Do you know what the oil pressure use to be? If you have the previous pump, maybe try that one.
LOUIS AMSLER
Member
I have a book on '63 Ramcharger wedges. It has reprints of the service bulletins, one of which states that it's ok if the oil light comes on at idle (!) if it goes out in neutral or higher. Those things had a 50K warranty, believe it or not, so I guess you don't need to worry about it.
BSB67
Well-Known Member
Right. But the the 63 Ramchargers had a reason for low idle oil pressure.
miller
Well-Known Member
Pretty sure, in my 64 book, says oil light switch kicks in at 8 lbs.
I call my 440 oil pressure too low, running both a gauge and light. Though, not sure, but real possible my 1/2" pickup tube has some effect on that. Warmed up, mine idles with 25 lbs, tops at 45-50 lbs. Once I get to it, kick it up 10 lbs.
I call my 440 oil pressure too low, running both a gauge and light. Though, not sure, but real possible my 1/2" pickup tube has some effect on that. Warmed up, mine idles with 25 lbs, tops at 45-50 lbs. Once I get to it, kick it up 10 lbs.
moper
Well-Known Member
All great bits of advice.
Sonny
It’s all fun til the rabbit gets the gun.
Just wondering. There are 2 plugs behind the intake. One has the low pressure light sender and I put the fitting for the aftermarket oil pressure gauge in the other. Is that the best place for it?
PRHeads
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I always ran 20/50 in my stuff.
My 383, which retains the original 100,000 mile std volume pump, with the addition of a MP high pressure spring has 80psi going down the track, and about 40psi hot idle @1100rpm.
On a fresh build I wouldn’t want to see 12@ idle and 40-45 going down the road...... but I am pretty old school in that regard.
What oil filter do you have on it, and exactly which 10/30 are you running?
I don’t see the harm in trying to either shim the relief spring or replacing it with the high pressure one.
It’s certainly possible the spring is either slightly softer than it “should” be, or perhaps it’s installed length is longer than spec.
If changing the spring pressure had little to no affect on the higher rpm pressure, then you know the capacity of the pump can only deliver “x” pressure into the amount of downstream leakage your motor provides.
My 383, which retains the original 100,000 mile std volume pump, with the addition of a MP high pressure spring has 80psi going down the track, and about 40psi hot idle @1100rpm.
On a fresh build I wouldn’t want to see 12@ idle and 40-45 going down the road...... but I am pretty old school in that regard.
What oil filter do you have on it, and exactly which 10/30 are you running?
I don’t see the harm in trying to either shim the relief spring or replacing it with the high pressure one.
It’s certainly possible the spring is either slightly softer than it “should” be, or perhaps it’s installed length is longer than spec.
If changing the spring pressure had little to no affect on the higher rpm pressure, then you know the capacity of the pump can only deliver “x” pressure into the amount of downstream leakage your motor provides.
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Sonny
It’s all fun til the rabbit gets the gun.
Using a wix filter and VR1 10w 30 racing oil.
steve from staten island
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I went with a Sealed power pump also and now that I'm having my 383 rebuilt, i will be asking my guy what kind of pump he will use.
I always thought low oil pressure could be because of excessive main and rod bearing clearance, either the way it was set up or high millage wear.
I assembled my original 383 myself and used plastic gauge to check clearance's, mine were within factory specs as best i could tell and the engine spun over with little effort. Maybe to much little effort. My oil pressure was kind of on the low side or so i thought. Im having this engine done by a shop with a excellent reputation and i will talk to the rebuilder soon about this subject.
In the meantime Happy New Year!!!!
In my experience bearing clearance made very little change in oil pressure. The current motor has had 2 different cranks. The 1st had journals -.001". Replacing the bearings with -.001" to tighten clearance did zero as far as pressure. Tightening the line bore dimension did nothing. The new crank is dead on standard. The aluminum rods were swapped for steel with a tighter big end dimension. During this time bearing clearance ranged from .0043" down to .0024". With all these changes, there was no change in pressure. The valve train area can create bigger internal leak paths causing excess flow. Thus low pressure. I agree with Dwayne. Try the spring or shim. if pressure remains the same, the pumps flow capacity is maxed out.
Doug
Doug
PRHeads
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I also think it’s too cheap and too easy to not try some 20/50 and a Wix race filter(51515R).
I’d actually do the spring(MP P4286571), the 20/50, and the race filter all in one shot.
And, if that provided satisfactory results....... for the next oil change I’d start using Driven Hot Rod synthetic 15/50 as my normal fill for that engine.
I’d actually do the spring(MP P4286571), the 20/50, and the race filter all in one shot.
And, if that provided satisfactory results....... for the next oil change I’d start using Driven Hot Rod synthetic 15/50 as my normal fill for that engine.
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Sonny
It’s all fun til the rabbit gets the gun.
Spoke to my engine builder. He too was not concerned. Said I could go 10/40 if it bothered me, but those numbers we correct for stock tolerances.
BSB67
Well-Known Member
Good. If you believe that, I would not waste my time checking or changing anything.
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