73 roadrunner oil

[Stw72]

Need help inherited a 73 roadrunner with 340 in it an I don't no jack #$%^ bout cars what oil should I put in it.

 

[V.R.D]

if you run it hard i.m.o i would use 20w50 brad penn green oil

 

[Stw72]

Ok thanks someone told me stp but I'm going with wat u say.

 

[69hemibeep]

Part of it depends on the climate you live in. That said you need an oil with zinc phosphorus in it to protect the cam and lifters. Some guys will recommend heavy oils but its a waist of horse power trying to push that stuff between wear surfaces as wide as two sheets of paper and it drains back to the pan slower. OK let me have it about 50W oil LOL

 

[V.R.D]

straight weight oil is for top fuel engines .

the brad penn oil has zinc and sulfur like the old Kendall oil did

 

[V.R.D]

Ok thanks someone told me stp but I'm going with wat u say.

don't use stp it is way thick and is over kill with the oil's made today have got the best temp burn off protection

 

[Russ69Runner]

Like they say it depends on what part of the country you live in. Temp for summer and winter. Running a zinc additive in mine.

 

[Stw72]

live in the heart of Texas. Its lil on the warm side you could say. How bout castrol 20w 50

 

[69hemibeep]

20w-50w would work, multi weight is a good all around oil.

 

[TOMRR]

This works for me, I use the 20/50 in my 440

 

[Roadtrip]

Some also depends on the clearances in the engine. I only use my car in summer months between 55-90 degrees and run 10w/40. I use Lucas hot rod oil

 

[MoparDan]

Need help inherited a 73 roadrunner with 340 in it an I don't no jack #$%^ bout cars what oil should I put in it.

I'd do 10W40. 20W50 is too heavy

 

[69hemibeep]

Does anyone know just how smart a multiweight oil is? I'm sure it goes by ambient temp for the thin cold side and engine temp be thicker. Although Ive never known hot oil to act thicker I'll play along. How does it know and is 10w-40w just a ballpark figure? Ive never questioned it.

 

[MoparDan]

Oil weight is a term used to describe the viscosity of an oil, which means how well it flows at a specific temperature. The Society of Automotive Engineers (SAE) assigns a viscosity number, or weight, to oil based on its flow at 210 degrees F, which is roughly the standard operating temperature for most motors. Viscosity is the resistance to flow at a given temperature.
If you would like to know how the oil companies do it here is a link to good information. https://www.machinerylubrication.com/Read/29502/base-oil-viscosity