Too much oil pressure?
 

I have a newly rebuilt 455 with Butler Super Duty oil pump 80 psi pump at Cruise I'm seeing like 60 PSI, 30 at idle and if I give it a little gas it's it's going immediately to 80. Running RP 20-50 in FL about 75 deg.

Was thinking should only see 80 at like wide open throttle with the engine cold or something (not something I'd do). Just seems like a lot of pressure for not a lot of load.

This may be a dumb question...

Gauges are new Autometer so pretty sure I'm getting accurate readings.

I would say all seems normal to me. you're also using heavier oil (50wt)

Seems ok, that's about what mine does.

Why are you running 20/50?

What kind of cam?If roller run 10-30 syn.Tom

No kidding on the oil. With those kinds of pressures I'd have no problem stepping down to 10-30 or even 5-30.

Was running 10w30 Mobil one...but then talking with butler they were running 20w50...I think was a bit ago. Making that change made a dramatic difference in pressure.. just got me worrying. Maybe should split the difference & run Delo 15w40 diesel oil like I put my my truck :)

You do not need that kind of oil viscosity for that oil pressure, as may have posted.

A normal 10W30 oil may put you right there on a hot summer day.

Being as you are in Florida you could get by easily with a 5 weight oil
5W-30. I would try 10weight oil first.

Tom V.

If a roller cam run the moble 1 10-30

Shouldn't that be dictated by bearing clearance, not cam actuator?

You don't need to worry about the oil pressure you have,, it sounds right and will not be an issue. I wouldn't recommend going to 10-30, Butler built the motor and told you what was best to use.

It was suggested to me to go to 10-30 on my roller 455 motor, I have been running 15-40 which Kaufman recommended for years in my motor. All it did was help with lifter collapse, etc. and ended up costing me a bunch of money. Oil is recommended based on build and clearances. Follow what your builder said.

yes bendutro,
Although i can't comment on the cam actuator.

Generally speaking, a tight bearing clearance will need thinner oil. Especially on a cold start.
Allot of the hi-end euro stuff run tighter clearance. A thin synthetic is recommended.

oville, from the build sheet, whats the rod, main, and piston clearance?
Was the 20-50 a break-in recommendation?

I hope your also running the needed HD oil pump drive shaft ?

I would run 10w30, maybe even 5w30. Pumping 20w50 is way too thick. That strains the cam/oil pump drive gears.

Royal Purple pour ratings are excellent so I wouldn't sweat the 20w-50 too much.

Mine is very similar. I have 40 at a hot idle, and it will jump to 80 psi when you touch the gas and pretty much stays there in all conditions except idle.

Mine is set up with .002" main bearing clearance, .0015" rod bearing clearance. I've had everything from 10w-30, to 15w-40, and Amsoil 20w-50 in it and the oil pressure is always the same no matter what oil viscosity I run.

The engine builder that did mine recommended a 20w-50 Viscosity. I use Amsoil because it's pour rating is as good or better than most of your 10w-30 oils on the market. Been fine for 20+ years, half of that life was spent in Ohio. Now living in the desert climate of Arizona so I prefer more viscosity.

a 80 lb pump is hard on dist gears no matter what oil.With 20-50 it is really hard.Watch the dist gear if a bronze or poly gear.The factory used a big dist gear with all 80 lb pumps for a reason even with a iron gear.Tom

I wonder if its a good idea to have the oil pump constantly in bypass? There some power wasted and undue stress on the oil pump gears, oil pump shaft, cam gear etc.

As said a couple different ways above - oil viscosity should be determined on what pressures you are seeing during running. I shoot for 55 to 60 pounds hot oil pressure at 2,500+ RPM and will adjust the viscosity to get there. Cold starts dictate where the first number needs to be. A little high at startup says you should drop the first number. I was running 10w30 in the new blue GTO engine. Hot running pressure was right where it needed to be, but cold was somewhat high at fast idle. Next oil change adjusted to 5w30 and the cold pressure dropped 10 pounds while the hot stayed where it was. I have nothing against 20w50 weight oil, and run it in the drag car because that's what my bearing clearances want.

Just put together an engine for a friend and main and rod clearances were a little larger than what we wanted, but sometimes you get what you get with today's bearings. Broke the engine in with 30 weight, and hot running was 52 so we will be going to a 10w40 on next oil change to get the number up a little.

Butler recommends 80 psi pumps in all large journal or long stroke engines (above 4.21"). Here is a link to an article in Hot Rod where they explain why: http://www.hotrod.com/articles/hppp-...-observations/

I must be wrong we run 20/50 in everything haven't had any problems yet.

My 400 is exactly the same. 30 to 40 at idle, 80 on the highway.

About all the 80lb oil pump is going to do for you is to rob some power from the engine and put additional stress on the cam gear, distributor gear, and timing set.

More time should be spent by the engine builder to make sure the clearances are correct, and that you take steps to keep the oil pick-up tube covered at all times (get a better oil pan).

Even on really high HP applications we use the stock Melling pump with 60lb spring in it, zero issues to date at any power level, even full race stuff pushing some of these heavy cars into the 9's at the track year after year after year.

The Pontiac oiling system is excellent, or at least good enough for these engines w/o any additional help, and there is no need for more pressure considering the film strength of modern lubricants.....IMHO......Cliff

i agree with cliff & others that say too thick of oil is not good for an engine, high oil psi does not mean it is lubricating better. flow = lubrication or an oils ability to keep parts seperated by a film, & flow increases cooling. pressure at the bearing entrance does not equal flow. 20/50 oil is usualy used for all out race engines with bigger bearing clearances that allow that oil to flow properly. street engines, which the majority of these cars here have, are not built like a race engine, bearing clearances are on the tighter side, useing 20/50 oil in your street engine is just causing extra stress on cam/dist gears & oil pump drives but more important is causing more wear especially at start up & robbing a little power.

having 40psi at hot idle is simply not needed, general rule of thumb is 10psi for every 1000 rpm. why would you want or think you need more psi than that? more psi is not better in this case. the most important thing for oil to do is to lubricate & cool the engine & it does that by flow. more flow= more lubrication & cooling... a thinner oil, within reason, is how you get more flow. psi does not = flow. period.

i love reading these oil threads, so many misonceptions & flat out misunderstandings about things like zddp, oil weight, psi, etc etc. proper oil weight, as mentioned by a few people above, is dictated by bearing clearances & pressures when running, not what someone tells you without taking in to account the engines purpose or the climate its operated in. just because a "mechanic" or anyone says you need to run this oil or that weight because thats what his grand daddy told him 40 years ago does not mean its true. & if someone says use 20/50 oil for a street car, regardless of the engines specs or climate the engine operates in, they are probably just a little out of touch on todays oils & what different engines need.

butler builds all kinds of engines from 400hp street engines to 1000hp+ race only engines, i highly doubt they all need 20/50 oil... i have a butler stroker kit in my 500+hp STREET engine, my local builder who did the short block builds all kinds of engines from 350hp street engines to 1500+hp blower engines, from drag race cars to truck pulling & circle track & is one of the most reputable engine shops in the area... funny he suggests 10/30 oil for my engine, & only uses thicker oils in dedicated race applications. he must be crazy!

save the thick 20/50 oil for race applications & use a more appropriate thinner oil for your street car. a 400hp engine driven on the street is not a drag race engine & does not need race only oil & 40psi at idle.

In the article posted, butler claims "the amount of time it takes pressure to climb to 60 psi or more can put the bearings at risk on a quick-revving, high-performance engine.".

FWIW...One of the reasons Ferrari and other fast revving engines use lighter oil. 0W-40 is gaining a ton of traction. Flows like a banchi when cold and has the 40 weight properties when warm. I am a huge fan of synthetics. More consistent oil pressure across the board.

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Unless you put together your own engine, own dial bore gauges and know every clearance in your engine, don't just guess and put any old oil in. Listen to the builder.
That being said not all 10-30 20-50 5-40have the same pour values either. 4 different 20-50 oils by different manufacturers can have a different pour value, which will alsoeffect how it gets thru the motor cold.
Do what works and has been working for ya. my .02

Yep I mentioned that. Seems people still stick to the old 20w-50 is too thick scenario without looking at the oil properties and additive packages. They've come a long way since the 1960's.

When I break an engine in I see the same thing and just went through this in the last couple weeks with a Pontiac engine. When I broke my engine in, cam run in etc...., I did it on 10w-30 break in oil. It still had 40 psi hot idle oil pressure. I changed it to a 15w-40 with a bottle of EOS for some more run in time on the street. Oil pressure still the same. When I switched to 20w-50 Amsoil synthetic, the oil pressure doesn't change.
Quite frankly, even my engines here with stock oil pumps have a hot idle oil pressure readings of at least 30-35 psi. I've never had any engine idle hot with 10psi or less unless it had an internal problem that needed a remedy, lol. Usually the culprit was worn cam bearings, or the engine was just flat worn out. They will run without issues like that, because I've done it, but I'm not going to sit here and tell someone it's okay or it's normal, because it's not. There is an underlying issue as to why that's happening.