Oil recommendation: carb'd 5.0

[BLAKE]

Time for an oil change on the hot rod. I've run dino juice so far, but I'm open to switching to synthetic. What brand and weight would you guys put in a '91ish 5.0 with a Holley carb, decent cam, aluminum heads and forged pistons?

Built about 10 years ago and has maybe 10K miles on it.

[GrayStangGT]

This is what we have been running in older carbed motors, it comes in 20w-50 as well.

https://www.amsoil.com/shop/by-product/motor-oil/gasoline/z-rod-10w-30-synthetic-motor-oil/?code=ZRTQT-EA

[blandnuts]

When I switched from dino to synthetic blend I had just about every gasket blow out or leak. It had way more than 10k though.

[BLAKE]

This is what we have been running in older carbed motors, it comes in 20w-50 as well.

https://www.amsoil.com/shop/by-product/motor-oil/gasoline/z-rod-10w-30-synthetic-motor-oil/?code=ZRTQT-EA

Thanks, appreciate the recommendation.

When I switched from dino to synthetic blend I had just about every gasket blow out or leak. It had way more than 10k though.

Hah, well that's not what you want.

[JV106]

I don’t have a recommendation but I think your type of cam/lifters plays a big role in this decision.

[cool cat]

I would stay with whatever the factory recommended oil is, as long as its a good brand. What is the factory weight/viscosity for a roller motor, I am probably about to upgrade mine.

[Baron Von Crowder]

I have been using the motorcraft synthetic blend.

[Strychnine]

I don't have a specific preference, but I can give you this...
I handle tech for the fuels side of our business, so oil's not in my wheelhouse, but my counterpart who's our tech expert for our base oils said he's a Mobil 1 guy. He's been in lube oils for 30 years, mostly representing Lubrizol (they make the $$$ custom additive packages that all of the oil manufacturers need - additives make up 15-30% of engine oils by volume). If there's one person in the world I'd trust for an oil recommendation it's him.

[BLAKE]

Good stuff, thanks guys.

[mustang_revival]

I don't have a specific preference, but I can give you this...
I handle tech for the fuels side of our business, so oil's not in my wheelhouse, but my counterpart who's our tech expert for our base oils said he's a Mobil 1 guy. He's been in lube oils for 30 years, mostly representing Lubrizol (they make the $$$ custom additive packages that all of the oil manufacturers need - additives make up 15-30% of engine oils by volume). If there's one person in the world I'd trust for an oil recommendation it's him.

It's nice to hear something good about Mobile 1. It's all I've ran for the last 10 years or so and recently(4-5 years) there's been some bad articles / various feedback on it..

[johnboy]

I've used Mobil 1 oil and filters for all my cars and trucks for over 20 years. My 98 stang has 203k and has never been opened up, only clutch, pressure plate, throw out and rear main seal. I change at 5k and it is only about 1/3 of a quart low after filter drains.

[jw33]

Quaker State with a can of Slick50.

[svauto-erotic855]

If it has a slider cam stick with oil advertised as being for a diesel engine or any of the big brand names that say high mileage or racing on the bottle. If it has a roller cam get any premium 10w30 synthetic; I use Royal Purple because it is a real synthetic oil (unlike Mobil1) and it can be found at any Walmart.

I second using Mobil1 filters. They are top rate and I have yet to find a filter that uses thicker metal in their construction. I believe that the Wix XP line is also great and I use them the most.

Do yourself a favor and buy your oil filters in bulk from Rockauto; they cost less than half of what the store sells them for.

[Strychnine]

Not arguing, just discussing...

I use Royal Purple because it is a real synthetic oil (unlike Mobil1) and it can be found at any Walmart.

I'm assuming by "real" synthetic, you mean it's a Group 4 base stock?
Even though RP is a Group 4, there's going to be some Group 1-3 blended in there. It's hard to get pure Group 4 base molecules to carry the entire additive package - they need to blend in some lower groups for their solubility.

I'd be curious to know if you have any quantifiable reasons to be set on RP. IMO, the additive package is more important and it will be engineered to work precisely with whatever base stock is used. I think the high group stuff is really more about friction modifiers and minimizing losses in new engines that need every bit of help they can get to increase efficiency. Gonna go out on a limb and say that in a hot rod (like Blake's talking about) no one's going to notice a difference, but I'm open-minded on it. If it's just price / availability, disregard.

When I switched from dino to synthetic blend I had just about every gasket blow out or leak. It had way more than 10k though.

Hah, well that's not what you want.

Some background here. I'm not sure what the exact industry consensus is on this (I'll ask around some technical guys, not marketers), but here's why most people blame synthetics for causing leaks (really "synthetic won't cause leaks, but in some cases it can find them" would be more accurate)

When you make the base oils for lube oils there are different Group classifications. Don't worry about the nitty gritty, but the molecules in Groups 1-3 are fossil based (longer hydrocarbon chains form petroleum that are refined and hydrocracked down into the length needed). Group 3+ is "Gas to liquid" (shorter hydrocarbon chains from natural gas that are reacted into to longer chains, at an exact length). Group 4 and 5 are engineered from ethylene.

Fossil based stuff will have a wider range of lengths in it (the orange line in the graph), including some larger / longer chain molecules that can help "seal up" old gaskets, degrading seals, etc. The thought is that sometimes when there's a change to synthetic the new detergent package will have a cleaning effect and then the lack of longer chains will not seal up those voids as well - hence the leaks.


Mineral = Groups 1,2 for all intents and purposes
VHVI = Group 3 (this is the majority of engine oils)
PAO = Group 4




I'm not saying I agree or disagree with the "longer chains cover up seal issues better", but this is why people say that.

[BLAKE]

There's the Matt we all know and love. It ain't a thread without charts and graphs!