What do you guys think about running straight 30w motor oil in our 5.2s?

 

What's the weather like where you live, cause the point of running multiweight oil is to help it on cold starts, but if the temp never gets too cold where you live it might be ok.

 

Its getting nicer of late. But it was down in the single digits for a while. Reason I ask it cause my grand father has used straight 30 weight for years and years and has been getting 40 miles to the gallon on his Crysler New yorker with a 318 in it.

(He has developed a second set of butterflies that allow the engine to keep compression while the car is coasting and not needing fuel, restricting the amount of fuel that it consumes while coasting.)

 

Thats really hard to believe that a 5.2 can get 40 mpg, but assuming it's true, I seriously doubt it has anything to do with the oil. If you live in an area with single digit temps, there's no way you would want to run single weight oil. When the engine gets up to temp it won't know the difference between 30w and 10W30 or any other mutiweight with the second digit 30. The W in multiweight oil stands for "winter" and refers to the viscosity at cold temps.

 

actually the W stands for weight as in 5w has 5 weight base stock,10w is 10, 15w is 15, etc. so it flows like the weight of oil it is at low temperatures. oil additives keep the oil from thinning when hot so it flows like a 30,40 or 50 weight oil at warm temperatures even though it is 5,10 or 15 base stock. have seen 20w20 and 30w30 motor oil,never could understand how that would be any different than a straight weight oil. unless it was just a marketing thing to make it sound like something different?

 

Actually the W does stand for Winter or Weather.

http://www.upmpg.com/tech_articles/motoroil_viscosity/

 

"Its getting nicer of late. But it was down in the single digits for a while. Reason I ask it cause my grand father has used straight 30 weight for years and years and has been getting 40 miles to the gallon on his Crysler New yorker with a 318 in it.

(He has developed a second set of butterflies that allow the engine to keep compression while the car is coasting and not needing fuel, restricting the amount of fuel that it consumes while coasting.)"


I wish I could get 40 mpg's on my 318, that's almost as good as a prius or a corolla and very very hard for me to believe. I'd recheck your math on that.
If he is truly getting 40 mpg's on his 318, he needs to market his research because he has doubled or more than doubled the MPG's of his motor and if he can do that with a 318, no telling what he could get out of a 4 banger. The EPA would love it. Neither him nor his family would ever have to work again, I'd let him know to contact someone about his fuel saving innovation.

 

actually he has and has an ad in the paper. so far he has installed around 20 or 30 of them. The only trouble is that fabrication is based on the vehicle and takes a long time to make and calibrate. He is 84 and doesnt have the strength to work all day anymore. So he does about one per week.

The only reason i mentioned it is cause he runs straight 30 year round and still gets that mileage so i dunno if it such a bad idea.

i trust his math beyond anyone elses as he has worked on cars since he was twelve.

if you are interested i can talk to him about making one for anyone who would like one.

 

its really not that farfetched seeing as how his 318 is in a car not a truck and being 84 he doesnt have a lead foot in the least.

 

Yeah but my dad drives a nissan sentra with a 1.8L inline 4, has a very very light foot, and gets about 35-36 mpg highway, its just really hard to believe any 5.2L V8 could get 40 mpg unless its was going down a hill with the wind and missing half the fuel injectors