Oil Viscosity Recomendation

Pennzoil motor oil
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Originally Posted By: T_Bortz
85 Merkur XR4Ti
2.3L Turbo
Roller Cam
Rebuilt with "looser than stock" tolerances


For the 29th time, how are you going to use this car??!! It makes a difference. Is it a racecar? Is it a daily driver? Are you just going to drive it 10 miles on the weekends?

500hp out of a 2.3L engine is massive. I would probably run 20W50 if it were mine.

70 PSI at cold idle isnt excessive. I had a car that would run 110 PSI at cold idle on a 20 degree day, but settle down to 25 PSI hot. That seemed excessive, but it ran fine and nothing broke.
 
On your engine a simple 15psi and some supporting mods should put you at about 300hp.

And 500hp I really don't think you're pushing too hard... Most of your money is in the turbo and headwork, right?

I think Rotella T6 would do fine in your engine... Give it a try and let us know what your oil pressure looks like. What is factory spec @ idle/rpm for your engine? If your hot pressure is good, your cold pressure will be good. Normally it is hot idle that has the lowest pressure...

When you say looser... what was opened up? Big end bearings? Do you have the build sheet so we can compare with OEM tolerances?
 
Originally Posted By: T_Bortz
Oil pressure just seems way too high to me. 60ish psi at start-up and its been mid 80's here.


My Buick has 65 psi at cold startup and anywhere from 39-43 psi at full hot oil temps. Ambient is ~ 100F.
 
Same here, oil pressure in my M3 is 60+ psi on cold start... running 5W-40 oils. Don't know why you want to trust a bunch of internet strangers... why not listen to your engine builder OR do you not trust him? But trust him enough to rebuild the engine...
 
I have owned my 4Runner for 5.5 years, every morning it's SOHC 2.4L 22RE has 75-85 psi of oil pressure at idle on cold startup, it has the same with 5w30 as with 20w50, once it warms up it has about 20 with 5w30 or 30 with 20w50, the 10w40 that's currently in it has 25 at a hot idle. All of these oils are on the pump pressure relief at any engine speed over 2500 RPM at 82.5 PSI. I wouldn't worry a single bit about the high cold pressure as the hot pressure at idle is right about where I'd personally want it to be. I really don't think anything needs fixing here to run the 40 wt oil, a 0w40 or 5w40 may reduce the cold pressure, but what's the need really?
 
Well i've now tried 3 different weight oils and all 3 had the same pressure on startup (60-70).

15w40 put me around 25-30 warm idle, 0w40 put me just under 25psi at idle, i tried 15w50, but before it got fully warmed up i noticed a valve cover leak and shut it down. So i don't know what pressure it would have given me warmed up.

Here is the deal... it's not that i don't want to use 15w40, its that I don't feel like an HDEO is the right oil for this application. I think a good quality synthetic that can take the heat would be much better suited.

This is not a "race car" but it does get driven hard. And the oil is probably going to take an extra beating due to having a partially filled block. So i just want a good quality oil regardless of weight.

Now, that being said, the oil pump is driven off of the aux shaft/dizzy. And these motors are known for shearing gears/pins for the pump drive. This is why a HP or an HV pump is taboo in these motors, due to the added strees on these components.

So having excessive oil pressure, i feel that i am putting undue stress on these parts.

I do believe everyone that said don't worry about idle pressure especially now that nothing really made much of a difference.

So i am now thinking about the following oil options:

Mobil 1 15w50
0w40 M1 mixed 60/40 with Mobil 1 15w50
5w50 M1

Thoughts?
 
I've got a 1969 Ford Mustang with an original 302 V8 which is mildly modified. When I had it rebuilt 49K miles ago I broke it in on Castrol 10w30 and have been using it ever since. When I lived in the S.F. Bay Area, where the ambient summer time temperatures are fairly mild, the engine always ran with fairly high oil pressure and temps about 25% up the highly scientific stock Ford "L-H" gauge. Now I've moved to the eastern suburbs of Sacramento where the summer time temps frequently are 100*+. The car is heating up in those ambient temps, with the gauge sometimes getting to "H", and the oil pressure is dropping off as the oil becomes less viscous. I am considering switching to Castrol 10W-40 or 20W-50 to see if that will sustain higher oil pressure in the beastly days of summer. Would that be an answer to my problem or am I just looking at the same bearing wear problems that precipitated the rebuild?

Oh yeah, I have used Mobil 1 5w30 in all my newer cars but I've been told that older engines with looser tolerances don't like synthetics. Should I risk switching over to Mobil 1 10W-40 high mileage in this old girl?
 
Last edited:
Originally Posted By: RagTop69
I've got a 1969 Ford Mustang with an original 302 V8 which is mildly modified. When I had it rebuilt 49K miles ago I broke it in on Castrol 10w30 and have been using it ever since. When I lived in the S.F. Bay Area, where the ambient summer time temperatures are fairly mild, the engine always ran with fairly high oil pressure and temps about 25% up the highly scientific stock Ford "L-H" gauge. Now I've moved to the eastern suburbs of Sacramento where the summer time temps frequently are 100*+. The car is heating up in those ambient temps, with the gauge sometimes getting to "H", and the oil pressure is dropping off as the oil becomes less viscous. I am considering switching to Castrol 10W-40 or 20W-50 to see if that will sustain higher oil pressure in the beastly days of summer. Would that be an answer to my problem or am I just looking at the same bearing wear problems that precipitated the rebuild?

Oh yeah, I have used Mobil 1 5w30 in all my newer cars but I've been told that older engines with looser tolerances don't like synthetics. Should I risk switching over to Mobil 1 10W-40 high mileage in this old girl?


Double post and a threat hijack.

If your coolant temp is getting to the H range on the gauge perhaps addressing the overheating is more prudent than addressing the oil viscosity.
 
Originally Posted By: T_Bortz
Well i've now tried 3 different weight oils and all 3 had the same pressure on startup (60-70).

15w40 put me around 25-30 warm idle, 0w40 put me just under 25psi at idle, i tried 15w50, but before it got fully warmed up i noticed a valve cover leak and shut it down. So i don't know what pressure it would have given me warmed up.

Here is the deal... it's not that i don't want to use 15w40, its that I don't feel like an HDEO is the right oil for this application. I think a good quality synthetic that can take the heat would be much better suited.

This is not a "race car" but it does get driven hard. And the oil is probably going to take an extra beating due to having a partially filled block. So i just want a good quality oil regardless of weight.

Now, that being said, the oil pump is driven off of the aux shaft/dizzy. And these motors are known for shearing gears/pins for the pump drive. This is why a HP or an HV pump is taboo in these motors, due to the added strees on these components.

So having excessive oil pressure, i feel that i am putting undue stress on these parts.

I do believe everyone that said don't worry about idle pressure especially now that nothing really made much of a difference.

So i am now thinking about the following oil options:

15w50 Mobil 1
0w40 Mobil 1 mixed 60/40 with 15w50 Mobil 1
5w50 Mobil 1

Thoughts?


Out of those options, Mobil 1 0W-40. You could also use Mobil 1 Turbo Diesel Truck or Mobil 1 5w30 HM
 
Looks like 'ole Delo is just chopped liver around this T6
wink.gif
 
FWIW, i changed out to Mobil 1 15w50 today. Took the car for 2 nice long rides and oil pressure seems decent. 60lb-ish on startup, 25psi at hot idle, 50psi cruising.

I guess we will have to see if this oil holds up now...
 
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