[oville]

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...

[oville]

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

[74Grandville]

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

[4dblnkldude]

Seems ok, that's about what mine does.

[64speed]

Why are you running 20/50?

[tom s]

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

[Will]

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

[oville]

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

[Tom Vaught]

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.

[tom s]

If a roller cam run the moble 1 10-30

[bendutro]

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

[torqhead]

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.

[Blued and Painted]

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?

[steve25]

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

[TedRamAirII]

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

[Formulajones]

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.

[tom s]

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

[TedRamAirII]

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.

[lust4speed]

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.

[grivera]

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/