Oil for boosting oil pressure in 1950s V8

Joined
Mar 19, 2022
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I rebuilt my 1959 Ford FE 352 engine last year. I opted for a melling standard output oil pump and standard bearing clearances. Thus engine has hydraulic flat tappet lifters. I've run Amsoil Z-Rod 10w-30 but I have alarmingly low oil pressure, 10psi hot idle, and 25psi going down the road at 2000 RPM. Oil pressure is measured at the oil filter adapter which is obviously the closest to the oil pump. Cold pressures are 45psi 650RPM idle, and 60psi at 2000.

I wish the oil pan were easier to remove and I'd simply install a high volume oil pump, but that is a bit of a challenge while the engine is in the car due to very tight cross member clearances.

Is the Z-Rod 10w-40 much thicker, or should I opt for the wicked expensive 20w-50?

I'm not completely sold on using a boutique oil for this application, I just have an Amsoil account and put 6 qts of Z-Rod on my last order. I'm open to other options. I could just Rotella 15w-40 or something similar. I put roughly 2000 miles a year on it, and was planning on a biannual oil change with the Z-Rod, but could do something else.

What do you guys recommend? This thing isn't a hot rod and will never see over 4000 RPM.
 

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Joined
Aug 25, 2018
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South Carolina
I personally don't consider 10 psi to be "alarmingly low" oil pressure. If it was mine, I'd send it and not think twice about it. I don't see a problem there.

Your rod and main bearing clearance will determine the oil grade. For a mild engine and typical street use and oil temp = 200-240°F....

.0034-.0039" = 50 grade
.0028-.0033" = 40 grade
.0022-.0027" = 30 grade
.0016-.0021" = 20 grade
 
Joined
Oct 9, 2004
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Cincinnati, OH, USA
I rebuilt my 1959 Ford FE 352 engine last year. I opted for a melling standard output oil pump and standard bearing clearances. Thus engine has hydraulic flat tappet lifters. I've run Amsoil Z-Rod 10w-30 but I have alarmingly low oil pressure, 10psi hot idle, and 25psi going down the road at 2000 RPM. Oil pressure is measured at the oil filter adapter which is obviously the closest to the oil pump. Cold pressures are 45psi 650RPM idle, and 60psi at 2000.

I wish the oil pan were easier to remove and I'd simply install a high volume oil pump, but that is a bit of a challenge while the engine is in the car due to very tight cross member clearances.

Is the Z-Rod 10w-40 much thicker, or should I opt for the wicked expensive 20w-50?

I'm not completely sold on using a boutique oil for this application, I just have an Amsoil account and put 6 qts of Z-Rod on my last order. I'm open to other options. I could just Rotella 15w-40 or something similar. I put roughly 2000 miles a year on it, and was planning on a biannual oil change with the Z-Rod, but could do something else.

What do you guys recommend? This thing isn't a hot rod and will never see over 4000 RPM.
Valvoline VR1 20W50 isn't that expensive, and would be a good choice for it. Rotella 15W40 seems to be a really good classic car oil too. A zinc additive won't hurt, either, I've used Rislone and Comp Cams with good results, just don't go too crazy.
 
Joined
Dec 26, 2005
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Upper Midwest
Why not try some store brand 15w40? Cost effective and probably solves your dilemma.

just my $0.02
This of course is the correct answer, just as it was when a similar question was asked recently. If you want to see if a higher grade oil increases the pressure then it doesn't matter which brand you try. Cheap and dirty test.
 
Joined
Feb 25, 2019
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Texas
Cheapest 15w-40 would help but 15w-40's tend to be around the high 14cst mark on average at 100c while 10w-40's are around the low 16cst mark. 20w-50's hover around 19 on average. I think an hdeo or gtx classic 20w-50 would be good.
 
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Just for grins.......... Is the oil filter adapter installed correctly with all the correct o-rings, seals etc??? "If" it was bypassing, this might cause your problem. Do you have the original oil filter canister/filter? Just a thought.
 

Fabulous50s

Thread starter
Joined
Mar 19, 2022
Messages
240
Were the cam bearings replaced?
Yes, and clocked correctly for FE engines. All bearings are new. Block steam cleaned, all oil gallery plugs removed and rodded/steamed and tapped and threaded plugs installed.

Oil pump is a 5 lobe rotor style. I inspected it prior to installing it in the engine.

Just for grins.......... Is the oil filter adapter installed correctly with all the correct o-rings, seals etc??? "If" it was bypassing, this might cause your problem. Do you have the original oil filter canister/filter? Just a thought.

Oil filter adapter and holes in the block were modified for increased oil flow as consistent with first generation FEs.

I have several 390's.
The rule of thumb was 10psi per 1000 rpm with the shop manual saying 35-55psi at 2000rpm.
I'd try off the shelf 15w40 and 20w50 and see what that gets you.
These stock motors don't need HV pumps when properly assembled.

That was my reasoning for going with the standard output Melling as well. I did all the oiling mods typically dine to FEs but didn't restrict the passages to the rocker shafts as some guys do.

I've built a few Euro engines, but this is my first mid century V8.
 

Fabulous50s

Thread starter
Joined
Mar 19, 2022
Messages
240
Cheapest 15w-40 would help but 15w-40's tend to be around the high 14cst mark on average at 100c while 10w-40's are around the low 16cst mark. 20w-50's hover around 19 on average. I think an hdeo or gtx classic 20w-50 would be good.
What is the cst number for Rotella 5w-40 @100C?
 
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