Olds 455 - 10w-60 Engine Oils (Redline & Pennzoil Synthetics)

Joined
Feb 10, 2023
Messages
9
I have an Olds 455 engine. These engines only had 2 bolt mains and a cast crank. They are low RPM torque monsters (shifting at 5,200 RPM but making 550 Ft Lbs of torque) but they suffered from weak cranks and weak main block webbing. The cranks and bottom end would "flex" under heavy loads and RPM and wipe out main and rod bearings. In order to avoid spinning & wiping a main bearing or rod bearing, extra main & rod bearing clearance has to be built into the rebuilds.

So typically an Olds 455 rebuild will see .003" on the rods and .004 - .0045" on the mains. This allows the engine to live but requires one to run a 50 weight oil. It's common for these engines to see oil pressures of 15-20psi hot idle and 45-50psi hot cruise (180F+ oil temps).

I noticed I get better hot oil pressure with the Valvoline VR1 20w-50 oil than I do with Mobil1 15w-50. I looked up the specs:

VR1 20w-50 Viscosity Index @ 212F = 20.5
Mobil1 15w-50 Viscosity Index @ 212F = 18.0

I am considering trying Redline 10w-60 which has a Viscosity Index @ 212F = 25.9
It has the highest VI at 212F out of all the oils I found. Pennzoil 10w-60 is close with a VI @ 212F = 23.2

I would estimate maybe a 5-10psi increase in hot oil pressure with the Redline 10w-60. Any pros/cons with running that oil?
 
I have an Olds 455 engine. These engines only had 2 bolt mains and a cast crank. They are low RPM torque monsters (shifting at 5,200 RPM but making 550 Ft Lbs of torque) but they suffered from weak cranks and weak main block webbing. The cranks and bottom end would "flex" under heavy loads and RPM and wipe out main and rod bearings. In order to avoid spinning & wiping a main bearing or rod bearing, extra main & rod bearing clearance has to be built into the rebuilds.

So typically an Olds 455 rebuild will see .003" on the rods and .004 - .0045" on the mains. This allows the engine to live but requires one to run a 50 weight oil. It's common for these engines to see oil pressures of 15-20psi hot idle and 45-50psi hot cruise (180F+ oil temps).

I noticed I get better hot oil pressure with the Valvoline VR1 20w-50 oil than I do with Mobil1 15w-50. I looked up the specs:

VR1 20w-50 Viscosity Index @ 212F = 20.5
Mobil1 15w-50 Viscosity Index @ 212F = 18.0

I am considering trying Redline 10w-60 which has a Viscosity Index @ 212F = 25.9
It has the highest VI at 212F out of all the oils I found. Pennzoil 10w-60 is close with a VI @ 212F = 23.2

I would estimate maybe a 5-10psi increase in hot oil pressure with the Redline 10w-60. Any pros/cons with running that oil?

What are your Horsepower and Torque Numbers? What are your cam specs at 0.500 lift? Is this a roller or flat tappet camshaft? What cylinder heads are you using? Have you looked at what Amsoil has in there 20W-50 motor oils?
 
Hmmm,

I should probably say that i haven't even seen an Olds engine in probably 20 years, but there's a whole ton of stuff out there with cast cranks and 2 bolt mains that doesn't need 60wt oil... and i'm not sure i understand how opening the clearances up helps...

But it sounds like its built eighth e big clearances and you've done your research, go with it...
 
What are your Horsepower and Torque Numbers? What are your cam specs at 0.500 lift? Is this a roller or flat tappet camshaft? What cylinder heads are you using? Have you looked at what Amsoil has in there 20W-50 motor oils?

540HP and 560 Ft Lbs

Hydraulic Roller .587 Gross Lift - Duration @ .050 = 232/236

Aluminum Edlelbrock Heads

Amsoil 20w-50 - Viscosity Index @ 212F = 19.5 (which is lower than VR1)
 
Hmmm,

I should probably say that i haven't even seen an Olds engine in probably 20 years, but there's a whole ton of stuff out there with cast cranks and 2 bolt mains that doesn't need 60wt oil... and i'm not sure i understand how opening the clearances up helps...

But it sounds like its built eighth e big clearances and you've done your research, go with it...

Bill Trovato is the nations best Oldsmobile engine builder. http://www.btrperformance.com/about_us.html

He recommends the extra clearances to prevent wiping out the bearings. Only other way to tighten up the clearances is to run a forged or billet crank and to upgrade the 2-bolt mains with a girdle ($4,000 for parts and machining). With a forged crank and girdle, you can run tighter clearances but still not as tight as modern engines.
 
540HP and 560 Ft Lbs

Hydraulic Roller .587 Gross Lift - Duration @ .050 = 232/236

Aluminum Edlelbrock Heads

Amsoil 20w-50 - Viscosity Index @ 212F = 19.5 (which is lower than VR1)
Nice Camshaft and even nicer Cylinder Heads, how many quarts of oil is this engine holding?
 
One of the flaws is that the oil drain back holes in the heads are too small. At high rpms it can suck the pan dry but fill up the valve covers.

The Olds 455 has many flaws from the factory 😄

I have the 7 quart oil pan and restricted cam bearings. That limits the amount of oil going to the upper end and keeps the oil down down in the mains and rods, where it is more needed.

It is also INTERNALLY balanced vs externally balanced (factory). The internal balance helps to prevent crank flex and stress. I am also running lightweight forged pistons and forged Eagle rods.

If you run the factory .0025" - .003 on the mains, at my power levels, you are guaranteed to wipe out the main bearings in a short while. The reality is the factory Olds 455 engine had a VERY short life. It would spin rod and main bearings within a few thousand miles if racing the engine. Most Olds 455's that were raced did not live long without wiping out a bearing.

The guys that race Olds 455's today, run the larger clearances and the engines live a long life, even if raced hard. Bill Trovato explains all this in his book: https://www.amazon.com/How-Build-Max-Performance-Oldsmobile-V-8s/dp/1613250738


Olds 455.jpg
 
Last edited:
Pettrix, please reconsider those bearing clearances. When I was young, I owned a 442 with that engine, rebuilt it 4 times the first year, learning about oiling issues. The Old 455 has multiple problems mainly with poor oil return from the tiny return holes in the cylinder heads, which then flow though similar holes in the lifter valley corners. Next the oil gallery (high pressure oil passage) holes are also tiny, drilled from each end and not exactly lining up at the center.

I recommend tightening up the bearing oil clearances to minimum spec, drilling out the oil galleries one or two sizes larger, drilling out the oil return holes and using aftermarket heads for better oil return, adjustable rocker arm studs and air flow. Otherwise modify the "C" heads (best airflow of any Olds head) from a 1966 engine will work. Set the hydraulic lifters to 1/4 to 1/2 turn off the bottom to reduce excess oil flow to the heads. The 1/8" plate closing the end of the oil pump flexes and needs a heavier plate over it to reduce flex. Also, check the oil pump end clearance with plastigage. Cut the pump body down (I used a belt sander) to tighten these clearances. Debur the oil pump gears prior to final installation. The Toranado oil pan will give you an additional quart of oil.

The 2 bolt mains and cast-iron crankshaft don't hurt anything and are plenty strong. The only advantages that you will have, is that the existing connecting rods have "spit holes" at the cap flanges that oil these engines during idle conditions and there is a 0.030" oil gallery plug hole to spray oil at the timing chain.

And finally, the only headers that fit the stock exhaust ports well are Hooker 2". And these require you to cut off the air conditioning housing under the hood. Use 442 style exhaust manifolds if you like air conditioning.

I started with 20w50 oil and spin a rod bearing (loud squeal from the engine) within 5 seconds of turning the engine to 6500 rpm. I had oil pumped up from the valve covers into the air filter housing as soon as I looked under the hood.
 
VR1 20w-50 Viscosity Index @ 212F = 20.5
Mobil1 15w-50 Viscosity Index @ 212F = 18.0
Redline 10w-60 Viscosity Index @ 212F = 25.9


With the above info. Would Redline 10w-60 give the highest oil pressure at a hot cruise?
 
VR1 20w-50 Viscosity Index @ 212F = 20.5
Mobil1 15w-50 Viscosity Index @ 212F = 18.0
Redline 10w-60 Viscosity Index @ 212F = 25.9


With the above info. Would Redline 10w-60 give the highest oil pressure at a hot cruise?

Do you know what your oil temps are when you are driving this car? Dave at Redline said that his 20W-50 was not recommended if your oil temps were below 225 degrees.
 
That hot cruise oil pressure is fine. I'd stick to a 50 grade at most. But honestly I think I'd go down to a 40 grade. Wouldn't cause issues.
 
Do you know what your oil temps are when you are driving this car? Dave at Redline said that his 20W-50 was not recommended if your oil temps were below 225 degrees.

I have a probe in the oil pan. Typically see 180-210F on the oil temps.

What about the Redline 10w-60?
 
VR1 20w-50 Viscosity Index @ 212F = 20.5
Mobil1 15w-50 Viscosity Index @ 212F = 18.0
Redline 10w-60 Viscosity Index @ 212F = 25.9


With the above info. Would Redline 10w-60 give the highest oil pressure at a hot cruise?
it seems highly probable.

i'm assuming you changing it pretty often?
 
The 39 degree block is far better than the old 45/425 CID block. You did the right thing with your rod and main clearances.
Have a look at M-1 20w50 V-Twin. Vis@100C = 20.8

Edit; I think your cam is on the small side.

edit/edit... How come the seat angle on the heads is 60 degrees on the Olds and 45 on the BBC?
 
Last edited:
The 39 degree block is far better than the old 45/425 CID block. You did the right thing with your rod and main clearances.
Have a look at M-1 20w50 V-Twin. Vis@100C = 20.8

Edit; I think your cam is on the small side.

I do not think his cam is on the small side for the type of driving the OP is doing.
 
Back
Top