Just put Delo 400 15w40 in my '69 Bird

[James408]

I just replaced the Royal Purple 15w40 in my Pontiac 400 with some Delo 15w40. I made some interesting observations. The RP only had maybe a hundred miles and three months on the oil. After hearing so many good things about Delo 15w40, curiosity got the best of me. One observation I made, oil pressure with the Delo was closer to the conventional 20w50 I have used than the RP 15w40.

RP at 850 hot idle was about 16 psi. The RP
at 3000 was 59 psi.

Delo at 850 rpm hot idle was about 18 psi. 1000 rpm the Delo was 20 psi, 1500 rpm 40 psi, 2200 rpm 60 psi.

The Valvoline all climate 20w50 I use to run had 20 psi at hot idle of 850 and would reach 60 psi by 1900 rpm.

I have to say, I was so used to running a 20w50, I still worry about using the lighter oil. But the Delo does not seem to be that different from the 20w50, only a few psi.

I am not knocking the RP 15w40 because my motor's valvetrain seemed quieter and smother with the RP 15w40. Should I stick with the Delo?Car still runs like a scalded ape!!!

 

[Norm Olt]

Uh, about $4.??+ per quart closer, but does it make any difference, really...?

I'm sure there are always incremental gains to be made in almost every category: i.e., reduce the car's weight = more hp per lb. = greater performance = quicker 0-60, maybe?

But, just how much?

Better protection for 300 miles? Are these oil pressure readings really relevant or well within the normal parameters for an engine in this state of tune?

Not to worry about your OCI, eh? What kind of filter do you use?

Cheers!

 

[James408]

Hey Norm, how are you doing? I did not understand what you were trying to say with your reply.

I use a Napa Gold 1258 oil filter.

 

[James408]

Ok Oil dudes, I'm I too concerned about the oil pressure differences between the Delo and RP. To me this shows that the RP is thinner than the Delo but the motor seem to run smoother with the RP. I know that I am obsessing but what do you think?

Generally, is a synthetic in the same grade as a dino, thinner? Does the oil pressure being higher at an earlier RPM with the dino improved protection?

 

[JonS]

Are you wooried about pressures that are too high? Maybe go to a 10w-30 or even a 10w-40 to get lower pressures. Ever tried a straight 30 weight? Chevron makes a Delo 30w.

 

[James408]

Jon, thanks for replying. No, I am not worried about the pressure being too high. I just want to know if getting oil pressure up earlier in the RPM range(60 psi at 2200 compared to 60 psi not coming in until 3000) has a bearing(excuse the pun) on engine protection? I would never consider a 10w30 on this motor.

 

[rg144]

quote:

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Originally posted by James408:
To me this shows that the RP is thinner than the Delo but the motor seem to run smoother with the RP.

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I checked the VOA section. RP is 15.0 and Delo 14.5 at 100c. Of course no telling if that is exactly what your bottles were at.

quote:

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Generally, is a synthetic in the same grade as a dino, thinner?

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Being synthetic doesn't matter. The 40 refers to viscosity of the oil at operating temp. And it applies to a range of viscosities (you can check them here on BITOG link ). Castrol Syntec at 12 is as thick as they come in 30wt yet is a synthetic.

quote:

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Does the oil pressure being higher at an earlier RPM with the dino improved protection?

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That question has been debated before if you want to do a search. But just to note, some run 0w20 in Ferrari's with good result. The idea is low pressure does not mean low oil flow, in fact the opposite since there is less resistance to thin oil. Then they look for 10psi increase per 1000 rpm's IIRC. It works for them. I doubt it would in your '69.

 

[nickmckinney]

quote:

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Originally posted by James408:
Jon, thanks for replying. No, I am not worried about the pressure being too high. I just want to know if getting oil pressure up earlier in the RPM range(60 psi at 2200 compared to 60 psi not coming in until 3000) has a bearing(excuse the pun) on engine protection? I would never consider a 10w30 on this motor.

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Good rule of thumb for American dinosaur iron is 10PSI for every 1000RPM with a 15PSI idle minimum.

You are well above that so don't even worry, the oil changing any smoothness in that motor is probably in your head (I do the same thing myself)

 

[99]

Simple. Royal Purple is a racing oil per se, so it's more fluid than the comparable Diesel oil you have in there now. The Royal Purple is designed to go through the engine without alot of horsepower killing "drag". The HD Diesel oil is not racing oil, therefore it is thicker and creates more "drag" within the engine. That's how Royal Purple and the magazines can get more HP and Torque out of a engine by simply switching the oil. There's nothing wrong with running the diesel oil.....but you knew that 4 or 5 threads ago.

The 10psi per 1000 rpm rule is for stock, low performance engines in my opinion. For oil psi on a high performance engine, I like to see absolutely no less than 20 hot. 30 is a good place to be. Most any quality performance pump these days can obtain this and then some at idle. My 509 has ~45 at a 1100 hot idle with a Moroso pump. At 7200 it's at ~100. My personal take on oil psi and volume is you can never have enough. Sure it costs a little more power to pump it, but it's negligible when you have a ton of HP and torque to make up for it.

[ June 09, 2005, 09:16 PM: Message edited by: 99 ]

 

[James408]

Thanks guys for your replies. I feel better about my oil selection. I going to stick with the Delo and see how it does.