Oil recommendation for "hot rod" Pontiac

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CheezWhiz

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Hi all,

Wanted to get some thoughts from you, I have a 65 GTO with a 505 CID aftermarket Pontiac engine, aluminum heads and a mild solid roller (242 @ .050 on the intake). The builder prefers a 15w40 such as the Napa, Valvoline, or Rotella. The lifters are Isky "EZ Roll" which means they have a bushing instead of a needle bearing.

The car will see significant street use. I have the idle set at about 1000 RPM now to try and keep the roller lifters happy. I spoke with Isky and they said they'd prefer to see me run a 10w40 to keep the lifters happy, I guess they want to make sure the oil gets to the top end especially on cold startup.

Am I just splitting hairs here, and is either a 15w40 or 10w40 going to be fine? What do you think?

Thanks,
Steve
 
not much difference betweeen 10w40 and 15w40.

Id run a 15w40 dual rated diesel oil they usually have more zinc than a pcmo 10w40
 
I do have an oil pressure gauge, seems to get about 20 PSI at hot idle and go right up to 60 quickly with 10w40. Has a 60 PSI bypass pump and won't go over 60 PSI no matter how high I rev it, but I am probably looking at 6300 RPM shift points at max.

Is zinc a concern with the roller cam? Isky didn't seem to concerned about the zinc levels.
 
Originally Posted By: CheezWhiz
I do have an oil pressure gauge, seems to get about 20 PSI at hot idle and go right up to 60 quickly with 10w40. Has a 60 PSI bypass pump and won't go over 60 PSI no matter how high I rev it, but I am probably looking at 6300 RPM shift points at max.

Is zinc a concern with the roller cam? Isky didn't seem to concerned about the zinc levels.


Correct...you have a roller cam. No huge lift and flat tappet problems....you rolled away any zinc/oil issues...LOL
 
So here's the thing. With a carbureted engine, a double pumper, and a lot of hot-rodding, am I better off just running cheaper oil and changing it every 1500 miles or so? Part of me feels like generic 10w40 changed every 1500 miles would be better than high-end oil changed less frequently.

Maybe once I get a wideband in and really nail down the mixture that will be less of an issue, but right now I am conservative on the tune (i.e., rich and not too much timing).
 
If you think fuel dilution is going to be an issue....use a good 15w40 and change out often. Only a UOA will tell how much fuel dilution is present, but with the amount of $$$$$$ you have invested....a fifty buck preminum oil change is cheap insurance.
 
Originally Posted By: LargeCarManX2
If you think fuel dilution is going to be an issue....use a good 15w40 and change out often. Only a UOA will tell how much fuel dilution is present, but with the amount of $$$$$$ you have invested....a fifty buck preminum oil change is cheap insurance.


That's exactly what I'm thinking. If it were a "regular" car, you can cheap out on oil, but a cool car like that, saving a few bucks on oil would be the last of my worries. (You could always save the used stuff and either put it in an old beater if you have one or give it to someone who does, like me).
 
Cool! I like it when people stick with the original engines instead of just swapping in a Chevy.

What are the valve spring specs?

I don't know if a 15w40 will do any better than a 10w40 at resisting fuel dilution. The 15w40 will not thin out as much at low temperatures where viscosities are very high anyway, but above 160F, both oils are going to behave like 40-weights. Can you get Brad Penn 10w40 in DC? Or I suggest a 50/50 blend of Valvoline VR1 10w30 and 20w50.
 
Oh, I am fine with using a quality oil, nbd. I thought the main reason to get a better oil was for it to last longer, I didn't want to throw $ out the window if I was going to change really frequently but if there are other benefits besides longevity I will stick with a quality oil.

Engine is a "Pontiac," but it's an aftermarket block. Kind of like using a World or Dart block in a Chevy. Not sure on the spring specs, but I imagine they are pretty mild - it is a "street roller."

Also, in Spokane now! I can definitely get the NAPA 15w40, which is one of the oils my builder recommended. I would expect the Valvoline to be available locally too.
 
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Why a high mileage oil? Maybe it wasn't clear, but it's a brand-new engine, less than 1000 miles.

I am not sure about synthetic, at present I have some minor oil leaks. If I can get those taken care of I will consider synthetics, but for now I'm looking for dino oil.
 
Originally Posted By: CheezWhiz
Why a high mileage oil? Maybe it wasn't clear, but it's a brand-new engine, less than 1000 miles.

I am not sure about synthetic, at present I have some minor oil leaks. If I can get those taken care of I will consider synthetics, but for now I'm looking for dino oil.


I wonder if you would consider a syn blend like Maxlife?

Seriously, fix the leaks and run M1 0W-40. It's spec for my 370 ci/425hp motor and for a ton of expensive German machinery. It'l make that Poncho sing!
 
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Certainly the plan is to fix the oil leaks, but that may be more difficult than you'd expect. The aftermarket block has a lowered pan rail, and a lot of folks have issues getting it to seal. I have some work to do on my PCV system and possibly install a vacuum pump, but for now I am focusing on doing my 1000 mile oil change with a good dino oil. I may try s blend and see how it goes.
 
Originally Posted By: CheezWhiz
Certainly the plan is to fix the oil leaks, but that may be more difficult than you'd expect. The aftermarket block has a lowered pan rail, and a lot of folks have issues getting it to seal. I have some work to do on my PCV system and possibly install a vacuum pump, but for now I am focusing on doing my 1000 mile oil change with a good dino oil. I may try s blend and see how it goes.


Dino or Synthetic....it will leak the same. I alway's went 500 miles on a break in oil and changed it out. But that was decades ago, guess break in time on oil has doubled as well....LOL!
 
Seems to me good HDEO is also cheap. Walmart is showing Shell Rotella T at $12.97 for 1 Gallon. I would run HDEO and change often for dilution reasons.
 
We changed the oil after a dyno session, and once again after about 250 miles in the car. This will actually be the third oil change coming up and the first oil that will see over 1000 miles.

I keep waffling between the HD 15w40 and a 10w40, the only real reason for the 10w40 would be to get oil to those solid rollers sooner. I should probably run the Rotella, Napa, or Valvoline 15w40 as recommended by the builder this oil change and just keep an eye on the lash. If the lash opens up at some point I can revisit the oil weight issue.
 
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