30w oil
 

was told the other day that one of the fellas was using 30w diesel oil in his car any pros or cons from what i read it has different detergents

Re: 30w oil
 

I use Shell Rotella 30W diesel oil; the previousowner mentioned that the zinc in the oil helps with the babbit bearings.

Re: 30w oil
 

Don't think Rotella has zinc any more. Its a moot point in an A as zinc was not an additive when the Model A was new. Zinc was introduced for the high compression engines of the 50's and 60's

Re: 30w oil
 

30W is fine for summer, I use 10W30 year around.

Re: 30w oil
 

Zinc is a type of extreme pressure additive to prevent/reduce cam lobe/lifter wear in engines with high valve spring pressure. It had nothing to do with Babbitt bearings. Not needed there.

Re: 30w oil
 

Note that the temperatures are in Centigrade (Celsius).

Re: 30w oil
 

Valvoline VR1 racing oil has zinc, get at NAQPA

Re: 30w oil
 

Hey Jynx, if you look for previous posts regarding motor oils you will find enough opinions to keep you busy for days. At the risk of being labeled a heretic I doubt that you could find a motor oil for automobiles that would not be adequate for a Model A.

Re: 30w oil
 

I agree with that. Engine oils in the day were not very good. Even the cheapest oil available today is light years ahead of anything they had back then.
I use what ever oil is on special at the shops - usually 20W50. With a 180F thermostat, the engine temperatures are high enough that it does fine.

Re: 30w oil
 

I use Walmart brand 20-W-50

Re: 30w oil
 

Rotella oil is fine for a Model A

Re: 30w oil
 

I agree with Synchro909. Oils today are so much better than in 1930 that anything would be better. We shouldn't get all wrapped around recommendations from 1930. They were fine for the technology of the day, but we've come a long way in lubrication!

As to viscosity, modern multi-viscosity oils mean you don't have to change oil between summer and winter. The chart posted by katy in post #6 shows the whole picture. I use 20W-50 myself in my old Fords and have never had a problem. 10W-40 would be fine also.

Re: 30w oil
 

Hello.


I am not sure if I have understood the core question correctly.

For vintage cars, a low viscosity can have the disadvantage that the shaft bearings leak leaking oil. Otherwise, a multi-grade oil is always better than a single range.

The most important is the API classification. Because of the non-ferrous metal compatibility. You should not go higher than "SC". Petrol engine oil API SC has anti-corrosion inhibitor, detergent cleaner, HD heavy duty additives. That is enough!

However, the oil still has to be changed many times (max. <1000 miles) because it runs without a filter and only then can the abrasion chips be taken out.

Re: 30w oil
 

From what I have read, not an expert.


One major reason for using multi grade oil is a large portion of wear occurs during motor warm up until the oil/motor is at operating temperature. Straight 30 weight thickens considerably at colder/cooler temps. A multi-grade like 10w30 will thicken to what a straight 10 grade oil thickens to at a cold temperature.


A lot of motors when the temp in late fall/early spring/winter do not warm up all the way unless using a thermostat or if partially blocking the radiator. So the straight weight 30 oil is thicker than ideal all at all times.


Use of a magnetic oil plug can catch quite a bit of the metallic bits that might be floating around in the oil, but if you are especially concerned about this the motor can be converted to an oil filter system. The figure most mentioned here is changing oil every 500 miles. Oil is cheap compared to chances of premature motor wear.

Re: 30w oil
 

The model A engine needs a certain amount of viscosity to cushion the bearings . Ford recommended 20w for winter and 40 w for summer . I use multi grade oil , but figure that a 10w whatever would be too thin to give the necessary viscosity for the older engines when warm . There is more to it than quick flow , in my opinion .

Re: 30w oil
 

used 15-40 the first go, now 10-30 synthetic

Re: 30w oil
 

Good evening!

These motors are unsuitable for low viscosity oils. The large installation tolerances require a thick liquid oil to maintain a hydrodynamic lubricating film in the crankshaft bearings.
In addition, a low-viscosity oil leads to increased oil consumption and the combustion residues in the combustion chamber got too much.

Re: 30w oil
 

My understanding of multi viscosity oil.


10W40 - has the viscosity of a straight 40 weight oil at higher/operating temperatures. Straight 40 weight oil when at low temps is much thicker viscosity, so does not flow/lubricate well.




Multi viscosity oil changes so it has the viscosity of a straight 10 weight oil at very cold temperatures, it is not the viscosity of a 10 weight oil at high temperatures which would be very thin.




So a 10w40 oil attempts to keep the same viscosity for both temperature extremes.

Re: 30w oil
 

You guys got that right! Use what every you want that will get you on the road.

Re: 30w oil
 

Please don't say "10 weight, 30 weight, etc. oil"! That 'W' stands for "Winter", NOT Weight!!

Re: 30w oil
 

I do understand the W for a 10W40 multi viscosity oil, 10W is for Winter.


I thought when you are talking about a single oil like the old SAE 30 ford oil, it was called weight. 30 weight, oil that is not modified. If not referred to as weight what is the proper term for it?

Re: 30w oil
 

Winter is a subjective term, depends on the particular region one lives in. When I think of winter I think of down to -30F or -40F.

According to: https://www.usclimatedata.com/climat...tates/usmi0220
It doesn't even normally get down to 10°F in Dearborn in the winter, so 20W is fine if one lives in that region.

Re: 30w oil
 

that is very old world thinking. just like the guys who tell you to use non detergent oils . why? if your engine is in good shape and bearings and rings tight, lighter oil flows better, and protects better than heavy oils with less chance of burning

Re: 30w oil
 

Gasoline engine oils from API SC upwards contain additives that attack non-ferrous metals (bearing bronze) and white metals in the plain bearing shells of the crankshaft and connecting rod. Therefore it is better to use API SC.

This has nothing in common with the viscosity!



But the large tolerances of old engines always need a relatively thick oil. Multigrade oil is good. But not with too low base viscosity! Every oil - even multi-range! - becomes thinner with increasing temperature. A multigrade oil only becomes "slower" thinner. Therefore, 10W-XX is less favorable for these engines than 20W-XX.

I worked as a consultant in the lubricants industry and have my own mix: SAE 25W-50 in class API SC.

Re: 30w oil
 

Before the addition of the"W" designation, oil was catagorized by its SAE number (usually abbreviated as No.). For example, S.A.E. 10 or No. 10, etc. The term "straight" was also used; as in "Straight 10".

As refining methods improved, it became possible to produce an oil that had identical hot viscosity as No. 10 oil, but would flow at a lower temperature than 10. S.A.E. created the "W", or "Winter" designation (10W, 20W, 30W, etc.) for these oils. You can find charts online that give the temperature ranges for each viscosity.

Re: 30w oil
 

mine has run happily on diesel grade 15-40, 15-40 synthetic and now 10-30 synthetic. modern oils are so much better that I don't really think it matters very much what you put in it

Re: 30w oil
 

Wear happens with cold, thick oil.


At no point in normal operation will a 0W-40 get thinner than the SAE40 - they are both the same viscosity when hot, which is when they are the thinnest.


They BOTH thicken as they cool.



A 0W-40 works better than a SAE40, because it thickens less when cold - they're both as thin as each other when hot though. The difference is that the 0W will flow better cold, giving the best of both worlds.



It's a somewhat moot point though - not too many people are going to pay for 0W-40 and dump it every 1000 miles though!


Ours usually runs a 15W-40, more for cost/availability than anything.


How many model A owners even drive enough miles for the oil to impact the engine longevity anyway??? ;)

Re: 30w oil
 

x2 - You did a much better job of describing what I was trying to say.

Re: 30w oil
 

This makes sense to me but I remember reading in the owners manual for my Jeep that 5w-30 is only recommended for sustained temps below freezing AND that using 5w-30 in higher temps would lead to an increase in oil consumption compared to the 10w-30 recommended for above freezing use.

If they both flow like SAE 30 when hot (which they should), why would oil consumption change?

Re: 30w oil
 

Shell Rotella SAE30

Re: 30w oil
 

most common sense answer ever, put into words all can understand.