Moparts
Easiest way to lower oil pressure?
Posted By: Dart 340
Easiest way to lower oil pressure? - 03/24/10 04:14 PM
I need to lower the oil pressure in my 340.
It runs at 90 psi cold and 60 hot(2000 rpm). I changed to 10-30 oil to get these numbers, it
was higher before.
The engine was built for the strip and I just
dont need this much pressure. I get an occasional
6000 run, but not much above that often, and not
for extended time.
Would I be better off replacing the pump or trying to lighten the relief spring?
Posted By: topside
Re: Easiest way to lower oil pressure? - 03/24/10 04:21 PM
Easiest? 5W-20.
You're sure the gauge is accurate?
Posted By: Dart 340
Re: Easiest way to lower oil pressure? - 03/24/10 04:33 PM
Yes, the gauge is good. It's had both mechanical and
electrical gauges showing the same thing.
I found a fram filter will lower it 10 psi from
the wix that I am running now but that's not a
perfect option either.
Posted By: MoparforLife
Re: Easiest way to lower oil pressure? - 03/24/10 05:08 PM
Leave it alone. If you feel that you must have less pressure use a lighter oil. Personally I don't feel that you have a problem.
Posted By: HitIt
Re: Easiest way to lower oil pressure? - 03/24/10 05:55 PM
I agree. 60lbs hot is the sign of a healthy engine in my eyes. I'd only be a little concerned if it got over 100 when hot at a higher rpm like 4k. What is it doing then?
Posted By: stumpy
Re: Easiest way to lower oil pressure? - 03/24/10 06:01 PM
I'd be tickled to death with those pressures. Why mess with success. Stay as far away from the Fram filter as you can unless you like redoing your motor.
Posted By: Dart 340
Re: Easiest way to lower oil pressure? - 03/24/10 06:09 PM
Quote:
I agree. 60lbs hot is the sign of a healthy engine in my eyes. I'd only be a little concerned if it got over 100 when hot at a higher rpm like 4k. What is it doing then?
I just hate having to wait for it to warm up
before giving it some r's, and I was considering
using some Rhoades lifters and I think that high
of pressure at idle will defeat their working
benefit.
Posted By: stumpy
Re: Easiest way to lower oil pressure? - 03/24/10 06:13 PM
Why would you think that? If this is a new engine the pressure will go down with some run time.
Posted By: Dart 340
Re: Easiest way to lower oil pressure? - 03/24/10 06:48 PM
That pressure seems to high for the Rhoades to be
able to bleed down at lower rpms I am thinking.
Anyone have experience with Rhoades and bleed down
pressures?
It has about 2500 miles on it now I think.
Posted By: HealthServices
Re: Easiest way to lower oil pressure? - 03/24/10 06:51 PM
Does it sound like a mechanical cam? Meaning lifters ticking? If so it working.
Posted By: Mr.Yuck
Re: Easiest way to lower oil pressure? - 03/24/10 06:56 PM
spin a rod bearing, that'll do it. Really I don't see that too high. My old 440 ran at 80 (10-40) when 1st fired and 50ish when hot.
Posted By: AndyF
Re: Easiest way to lower oil pressure? - 03/24/10 07:04 PM
That does seem a little too high to me. My guess is that the engine was rebuilt with a HV pump rather than a standard volume pump? Only way to really fix it is to change pumps but that is a bunch of work on a small block.
Posted By: Anonymous
Re: Easiest way to lower oil pressure? - 03/24/10 08:07 PM
Lots of Melling SB pumps have the hole the relief valve is in about .100 to shallow thus making crazy high oil pressure--I bet it is a melling and has nothing to do with anything else in the engine--changing oil will not do it--swapping pumps will.
Posted By: RapidRobert
Re: Easiest way to lower oil pressure? - 03/24/10 09:00 PM
Quote:
swapping pumps will.
w you and Andy. main problem is that high of (cold) psi can burst a filter, lesser evil is it's a waste of power and wears cam gear/inter gear/shaft/bushing faster than normal for no good reason. If you are willing to pull the pan, rework that pump or swap it depending on your time constraints
Posted By: BSB67
Re: Easiest way to lower oil pressure? - 03/24/10 11:14 PM
You don't need to run lower oil pressure, those numbers are fine.
Posted By: smokkem
Re: Easiest way to lower oil pressure? - 03/24/10 11:25 PM
no you don't, unless it's blowing out of the breather
Posted By: dOoC
Re: Easiest way to lower oil pressure? - 03/24/10 11:34 PM
NO real EZ way to lower pressure on an A engine(like on a B-engine) ... but the benefits are not only saved HP on running the pump less ... but also less oil flying around hitting the crank and rods PLUS less oil on the cyl walls.
Posted By: MoparforLife
Re: Easiest way to lower oil pressure? - 03/24/10 11:57 PM
Quote:
NO real EZ way to lower pressure on an A engine(like on a B-engine) ... but the benefits are not only saved HP on running the pump less ... but also less oil flying around hitting the crank and rods PLUS less oil on the cyl walls.
For the type of driving it wounds like this vehicle will be doing he will NEVER notice any difference.
Posted By: dOoC
Re: Easiest way to lower oil pressure? - 03/25/10 12:14 AM
Quote:
Quote:
NO real EZ way to lower pressure on an A engine(like on a B-engine) ... but the benefits are not only saved HP on running the pump less ... but also less oil flying around hitting the crank and rods PLUS less oil on the cyl walls.
For the type of driving it wounds like this vehicle will be doing he will NEVER notice any difference.
His type of driving ? .. it is a race car. Now if he does not care about his ET ... I will stand corrected.
Posted By: RUNCHARGER
Re: Easiest way to lower oil pressure? - 03/25/10 01:50 AM
Put a pan heater on it, plug it in for an hour before you start it. After some use the pressure will come down a bit anyway. It is a bit high.
Sheldon
Posted By: deansrr
Re: Easiest way to lower oil pressure? - 03/25/10 02:03 AM
Posted By: RC91
Re: Easiest way to lower oil pressure? - 03/25/10 02:08 AM
It sounds like you have half groove main bearings with a high volume high pressure pump. I have seen small block blow out the filter or the gasket on the right angle adapter with that kind of pressure. Full groove mains will drop the pressure down to 60 cold, 30 hot, plus feed more oil to the rod bearings.
Posted By: Posest
Re: Easiest way to lower oil pressure? - 03/25/10 03:00 AM
My last three engines that I rebuilt have all run 80+ cold, pushing 100# when revved a little. They drop down to 50-60# hot. The teen I built has about 15K on it now and still runs 40# hot. My 340 and 408 are still on the high side but will come down in time and miles. I think that you will be fine.
Posted By: MoparforLife
Re: Easiest way to lower oil pressure? - 03/25/10 09:01 AM
Quote:
Quote:
Quote:
NO real EZ way to lower pressure on an A engine(like on a B-engine) ... but the benefits are not only saved HP on running the pump less ... but also less oil flying around hitting the crank and rods PLUS less oil on the cyl walls.
For the type of driving it wounds like this vehicle will be doing he will NEVER notice any difference.
His type of driving ? .. it is a race car. Now if he does not care about his ET ... I will stand corrected.
He states this: "I get an occasional
6000 run, but not much above that often, and not
for extended time."
So go figure. that kind of pressures he won't make a noticeable difference. People are racing and driving with that kind of pressure all the time. In the real world there are a lot more variables that will come into play that will change things a heck of lot sooner than that. Including driving consistancy.
On a good warm day you will be glad that you have a little extra to work with. that pressure will take care of itself and is not excessive to the point of being harmful. Nor will the pressures in this case contribute to a gasket or filter blowing out if quality parts and careful assembly proceedures have been used.
Posted By: Dart 340
Re: Easiest way to lower oil pressure? - 03/25/10 02:48 PM
I guess the second part of my question had to do
with pressure and usage of Rhoads lifters. If I
understand correctly, they bleed off oil at lower
rpms. Will they still function correctly at the
pressures I am seeing?
Posted By: HitIt
Re: Easiest way to lower oil pressure? - 03/25/10 03:28 PM
I'd ask Rhodes directly if it were me.
Posted By: MoparforLife
Re: Easiest way to lower oil pressure? - 03/25/10 03:52 PM
If your lifters were not bleeding down your engine would not run or it would be missing do to valves being held open.
This from the Rhoads sight: Q. Can a high volume or high-pressure oil pump be used with Rhoads Lifters?
A. Yes. As the bleed off is a function of rpm a high volume/pressure pump can be used without any problem at all.
Posted By: Dart 340
Re: Easiest way to lower oil pressure? - 03/25/10 04:11 PM
Cool, there we have it.
THanks.
Quote:
If your lifters were not bleeding down your engine would not run or it would be missing do to valves being held open.
This from the Rhoads sight: Q. Can a high volume or high-pressure oil pump be used with Rhoads Lifters?
A. Yes. As the bleed off is a function of rpm a high volume/pressure pump can be used without any problem at all.
Posted By: 70Cuda383
Re: Easiest way to lower oil pressure? - 03/25/10 07:00 PM
while the numbers sound a tad higher than normal, I wouldn't be concerned. high oil pressure when cold and having to wait till it warms up to beat on it?
You should wait for it to fully warm up anyway before beating on it. cold parts fit looser than warm parts, and beating on a cold engine might be bad for the piston skirts.
I like to wait until my oil pressures start to drop, indicating that the oil is warmed up and the rest of the engine is at operating temps...before I beat on it.
Posted By: RapidRobert
Re: Easiest way to lower oil pressure? - 03/25/10 07:47 PM
Quote:
I guess the second part of my question had to do
with pressure and usage of Rhoads lifters. If I
understand correctly, they bleed off oil at lower
rpms. Will they still function correctly at the
pressures I am seeing?
From what I understand your choice of viscosity is what affects the controlled bleed down rate of Rhodes (& similar) type lifters as in thinner will bleed them down faster and in effect tame down more a wild cam than a thicker oil would and that there is a more recent brand of (Rhodes type bleed down) lifters that are much quieter than the been around forever Rhodes' but are slightly less effective. Cant remember the brand.
Posted By: terzmo
Re: Easiest way to lower oil pressure? - 03/25/10 08:30 PM
numbers are fine...I run 20/50 and get a bit higher pressure at normal operating conditions than you do..same at cold...
I dropped My oil pressure by using thinner oil plus got My engine to run cooler by adding a 7 blade steel clutch fan...it ran hot in traffic. Had a 6 blade alum flex fan and it did not do the job.
Posted By: ohiodemon
Re: Easiest way to lower oil pressure? - 03/25/10 10:40 PM
leave it alone.
(love the banna)