oil

[scooder]

Hoop,
I've read your bit a couple o times now, what's not clear from your posts is the difference between the 0w 5w 10w and so on. To be clearer here. It wants say 50 "grade" when hot it still wants the same "grade" when cold. So why is there different W grades for 50 grade oil? If 0w is the 50 when cold in a 0W50 oil, then what is 5w with 50 grade? And 10W and 15W and so on, they can't all be the cold grade of 50 can they? One of them is right all the others can't be? Can they?
In the charts posted above the grades are clearly marked viscosity. So thin to thick?
I'm no oil expert, but it does definitely say viscosity!
Please enlighten me, I like learning stuff, but I question a lot. Thats how I learn.
Martin.

[Jack E/NJ]

Engine Oil Viscosity Chart
Numbers indicating what viscosities are like in the winter at the north pole.
0 gasoline
5 kerosene
10 diesel fuel
20 sewing machine oil
30 maple syrup
40 cornhead grease
50 crankcase sludge


Jack E/NJ

[Hoop]

Scooder, 0w, 5w, etc. refer how cold the oil can get and still maintain the desired viscosity. Simply, 0w can stand more cold than 5w.

For other stuff, if folks are interested, go on-line and start reading. No use in my trying to rewrite what is already there. Try to think logically about what the oil companies and auto makers want to do with oil. Some of the things guys post do not make sense.

[30-9]

Originally Posted by Hoop

Scooder, 0w, 5w, etc. refer how cold the oil can get and still maintain the desired viscosity. Simply, 0w can stand more cold than 5w.

For other stuff, if folks are interested, go on-line and start reading. No use in my trying to rewrite what is already there. Try to think logically about what the oil companies and auto makers want to do with oil. Some of the things guys post do not make sense.

With this logic in mind - 10-30 in winter and straight 30 or 20-40 in summer is ideal. I think

[40cpe]

This is an informative discussion. I was told about 25 years ago, before synthetic oils were popular, that the ingredient that the oil companies put in oil to make it multi-grade displaced lubricants. The greater spread between the "W" number and the highest number, the less lubrication in the oil. e.g. 10W-30 has more lubrication than 10W-40, etc. Maybe things have changed since then, but I try to use the highest "W" number for my climate and maintain the grade oil recommended by the manufacturer. For what other reason would there be so many "W" ratings? Why not make all multigrade with a 0 "W" rating?

[JSeery]

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Ok, from my recent reading! The w number ends up being the weight/grade of the oil, the addvatives allow it to perform as the higher number. Over time the oil can degrade toward the w weight/grade. This is mainly do to factors that are not encountered with a flathead (such as extremely high temperatures).

[rotorwrench]

As usual, contentious comments are all over the place and that is normal. These engines actually have fairly close tolerances when they are in properly overhauled condition. They are a carbureted engine so the oil gets more contaminants than our modern computer controlled cars. This only means that they have to have short schedule oil changes like every 2,000 to 3,000 miles or so due to more impurities and bypass type filtering if there is any filter at all (like the older engines). As to SAE viscosity ratings, they were designed for SAE 20 to 30 ratings for average cold to normal conditions. The only reasoning for higher viscosity would be as a fix for worn bearings with low oil pressure readings or looser tolerances for more power output.

The same things hold true for the modern multi-viscosity oils. The W is for winter operation or cold weather. An SAE 10W/30 rating is now the all year average oil by the OEM specs. Warmer weather can use 10W/40 or even 20W/50 but I would only use the 20W/50 if I had higher piston clearances for forged pistons or an extremely worn engine. The polymer plastic stuff that they put in the oil to give the higher viscosity breaks down faster on engines with carburetors so it still has to be on a tight schedule for oil changes, maybe even tighter than the straight grade viscosities.

Most of the 5W/?? or 0W/?? oils are so the modern cars will get all the advantages (crank windage) for mileage that the governments set forward. Same with skinny tires mounted on newer vehicles. They do every trick in the book to make them pass the standards. I would only use these oils in modern fuel injected engines. I still use SAE 10W/30 in all my modern 4-wheeled vehicles and 10W/40 in really hot weather.

Any oil is better than none but some are definitely more appropriate than others depending on ambient temperatures, area conditions, and how the engine is being operated.

[Alan O'Connell]

It states in the owner's manual that you should use SAE 40 between the temperatures of 100 degrees and 30 degrees. I live in Massachusetts and the temps in the summer are no higher then the mid nineties and the spring and fall are in the 40's and 50's. those three seasons will be my driving time. So I suppose I should use the recommended oil. I'm thinking that today's oil is probably better, though, because the technology for refining it is better and we have had 80 years to experiment and learn.

[Diavolo]

Just listen to Hoop. That being said, here is what I use to judge if an oil is the right thickness. After the engine is warm, I see oil pressure at idle and at 3000 rpm. At idle, if it's at least 6 psi for ~600 rpm, it's good. If it's at least 30 psi at 3000 rpm, it's good. If it's pegged when HOT at either point, it's too thick or something is wrong. If it's not at least these numbers, go to a heavier grade until you get at least 10 psi/1000 rpm.

Got this from bobistheoilguy and that's how I do it for everything now.

[Ronnie]

Here is the info

[big job]

And then on the flip side of the coin, In the commercial world I use rotella 15-40
in a 1950 F6 V8 salt sander. It may run 24hrs straight, and then it may idle for
5 or so hours "we never shut trucks off in storms" oil gauge needle runs little past
the center all day & night and idling. My 65 yr question on these 48-52 oil gauges
how come being a 80lb gauge and (30lb) is in the middle? don't cha think it should
be 40lbs???? but a test mechanical gauge reads 45lbs so why the 30??????

[flatheadmurre]

Originally Posted by big job

And then on the flip side of the coin, In the commercial world I use rotella 15-40
in a 1950 F6 V8 salt sander. It may run 24hrs straight, and then it may idle for
5 or so hours "we never shut trucks off in storms" oil gauge needle runs little past
the center all day & night and idling. My 65 yr question on these 48-52 oil gauges
how come being a 80lb gauge and (30lb) is in the middle? don't cha think it should
be 40lbs???? but a test mechanical gauge reads 45lbs so why the 30??????

Being a few years old and bimetal based that aint to bad...and you can calibrate them.
There are 2 settings of a KS meter to adjust it.

[flatheadmurre]

Originally Posted by Alan O'Connell

It states in the owner's manual that you should use SAE 40 between the temperatures of 100 degrees and 30 degrees. I live in Massachusetts and the temps in the summer are no higher then the mid nineties and the spring and fall are in the 40's and 50's. those three seasons will be my driving time. So I suppose I should use the recommended oil. I'm thinking that today's oil is probably better, though, because the technology for refining it is better and we have had 80 years to experiment and learn.

Just one little problem with the oil of today...its not designed to be superior to the engine only...its designed to be enviromental safe...not clogg up catalytic converters...give you a magic mileage...and other non engineering political BS.
And some of the oilwells had very low sulphur contents giving a clean oil to start with...not sure if any company today own the entire process of their oil.
I use a 15/40 from a farmsupply company here has the highest zddp i found in a non special oil today.

[Bored&Stroked]

flatheadmurre brought up an important point - the ZDDP content for our flat tappet cams. Almost ALL of the modern oils we see are for late model engines, with catalytic converters and roller cams. The friction reducing compounds have been stripped out of them.

So, regardless of the oil viscosity you run (and brand), make sure you have high enough ZDDP compounds for flat tappets (1200 or so) - or put in an additive in (especially during initial fire and break in).

I use Brad Penn - Penn Grade 1 break-in oil (30w) and their multi-viscosity Penn Grade 1 afterwards. They have the right levels of ZDDP and other additives for high-performance flat tappet cams.

[paul2748]

A lot of people have stated the "magic " number of 1200 for flat tappet cams. Look at the oil in the 80's - 600ppm of ZDDP (Pennzoil 10-40). Assume earlier years had a lot less. Where does this magic figure come from?

[flatjack9]

Everyone is still thinking overhead valve. When the flathead was introduced, they never heard of ZDDP.

[JSeery]

ZDDP is related to high valve spring pressure on flat tappet cams in OHV engines, not much of a concern in a flathead.

[flatheadmurre]

Originally Posted by flatjack9

Everyone is still thinking overhead valve. When the flathead was introduced, they never heard of ZDDP.

Originally Posted by JSeery

ZDDP is related to high valve spring pressure on flat tappet cams in OHV engines, not much of a concern in a flathead.

So why wouldnt we take advantage of a product that gives us a longer life of the cam and tappets ?

To avoid metal scuffing we have a few different aproches.

1. get an oilfilm in between...thats fine with a bearing that can contain the pressurised oil...not as easy with a tappet first slammed into the lifter and then dragged sideways...it can sure use a bit of help here.

2. we start adding somthing else the metal can slide on without scuffing beside the oil....all kinds of fancy metals has been tried here, This is the aproach ZDDP is taking.

3. Chemical additives affecting the metal.
Ok we dont want scuffing...what can we do to avoid it besides keeping metals from hitting each other ?
If we add something that lets the metal transform instead...its not magic...if we have some chemicals bond to the metal letting the high spots hitting each other fold over and become a smoother and harder surface instead of wearing off.
This is the aproach of an additive like X1r.

So will the engine run on a non dergent singlegrade oil with a minimum of additives ?
Sure it will !
Its a wonderfully forgiving engine.
The additives of your choice is to get an extended lifespan and less maintenance...

[JSeery]

Most modern oils contain ZDDP. Additional ZDDP should not need to be added above what is already in the oil for a flathead (if you select an oil with it in the first place}. But some additonal additive is most likely not going to hurt unless you over do it. If the ZDDP level is to high it can become harmful.

[Bored&Stroked]

When Do I Need ZDDP the Most: The time when I'm most concerned about the levels of it in my oil is during the initial break-in of a new engine, with a new flat tappet cam and lifters. The first 15 - 30 minutes of run-time have a whole lot to do with overall camshaft/lifter life.

Having a good break-in oil with high levels of ZDDP and other additives is a very smart thing to do. I use the Penn Grade 1 30W break-in oil. After that, I'll still run a oil with higher levels of ZDDP - as it surely won't clog your catalytic converter that you don't have on your flathead - so why not use it!