Another question about oil viscosity
 

Ok, as a little background, I just bought my first A just last fall. It is a 29 Tudor. I know nothing about the engine, except I did clean the pan and valve chamber, and it starts and runs really good with no smoke, and I don't think it has any really bad noises. I have not been around an A since I was 20 years old, and that was 55 years ago. I was a pro mechanic from 1964 till 1985. I am familiar with the splash oiling system in the old Chevys, and since the last 30+ years I am a pro OPE mechanic, I am certainly familiar with splash oiling of small air cooled engines. Which put out about the same HP per cubic inch as an A. My question (finally). is about the best viscosity to use, to protect the mains especially. I have been reading all the old posts here, and see that it sorta runs from 30w to 20w50 with STP added. I don't use this car in the winter in the winter, and will never be started with temps below like 50 degrees F. If I did want to use it in colder weather, I have a good pan heater that heats the oil in the pan up nicely in a couple hours. Also My attached garage never gets below freezing even in below zero weather. Anyway back to my concern, would to thick of oil not flow down the holes to the mains fast enough to provide proper lube? I have always kinda liked using STP in old engines, but they have always been pressure lubed. Right now I have 15w40 oil and one stp in it, but I have a fairly large stash of oils, including 10w30 5w30 full synthetic, and more 15w40 and more STP. I am not going to drive it long distances or high speeds. Mostly just around town with top speeds 35/40 mph, and max 10 miles .

Re: Another question about oil viscosity
 

10-30. 10-40, or 20-40 is all you need
STP or not.

Re: Another question about oil viscosity
 

Ford's original recommendation was 20 wt in the winter and 40 wt in the summer. So, your should be fine with 15W-40, plus you'll be prepared if for some reason you should want to start it up in cold weather.

Oil is one of those topics of endless discussion, debate, and pontification (e.g., thermostats, antifreeze, filters, etc. ). My impression is that a plurality of people (if not a majority) just use 10W-30 and call it good.

One of the legends (some would say, myths; others would say, truths) is that you shouldn't use detergent oil in a motor that may have been run with non-detergent for a long time because it will break loose chunks of accumulated sludge. I believe that this has now been long debunked.

Lubrication experts will point out that STP is not what they would classify as a lubricant, and it is well to remember that adding it, or any additive, necessarily dilutes the concentration of the real lubricants and other professionally vetted oil components. But, it's a testament to the Model A's durability that this, and many other dubious practices, can be followed with no apparent harm.

Steve

Re: Another question about oil viscosity
 

The reason I put in the A is because it is not a daily driver. Summer it probably gets started at most once a week, sometimes not for 2 or 3 weeks, and of course November till April it is put to sleep for the winter. SO, I thought the stickiness of the STP would cling to the bearings etc better when sitting. Maybe just oil stays good enough. I know some say STP is not a lubricant, but only a viscosity improver, but then why is it used by many as an assembly lube, which needs the best lube to prevent premature break in wear??

Re: Another question about oil viscosity
 

I can’t remember how many times I have given this same advice.

Over all my years owning Model A Ford’s this combination has worked the best for us.

Four quarts of 20w-50 Walmart motor oil, one blue bottle of STP, in engine, and Marvel Mystery Oil in the gas. John Deere Cornhead grease in steering box and u joint. If u joint is empty, could take a full tube. I pressure lube the chassis every 200 miles. Check transmission and rear end oil level regularly, and check your torque on the rear axel nuts offen. 100 foot pounds needed.

I have taken high mileage Model A engines that were making all kinds of noise. Dropped pan, cleaned completely along with pump screen. Tuned up. Added STP and MMO along with 20w-50 high detergent oil. You can almost hear the change from minute to minute. I do recommend changing oil after the next 100 miles or so. Rings and valves free right up.

Just my experience. I’m sure there are people that could question or find fault in my methods. But it works for us.

There great cars, the little kids love them. Enjoy.

Re: Another question about oil viscosity
 

OK WHN, I like your thinking, as I use MMO in all my classics, and I use cornhead grease also, the only difference is I am using 15w40 diesel oil and STP instead of 20w50. I was concerned that on startup that 20w50 with STP, would be so thick that it would not flow down to the mains fast enough. But I guess it works ok huh? I used 140 weight gear oil with about 40 % STP in the transmission, and just 140 in the differential.

Re: Another question about oil viscosity
 

Remember 20w-50 oil is 20 weight at cold start, that’s what the “W” stands for, winter. Than when engine is warmed up oil will not thin out less than a 50 weight oil.

I don’t think the STP will keep the oil from getting to bearings right away. Once you put STP on metal parts, it really sticks to the surface. It’s left on the bearings and other parts, does not run off.

Some people use all STP in both the transmission and rear end. We use 50/50 STP and 600 weight oil from suppliers. No oil drips.

We just drive our 29 from May until October. Like you, once a week or so.

Re: Another question about oil viscosity
 

I guess I should be good then. Thanks.

Re: Another question about oil viscosity
 

I use STP 100 percent in Transmission and 50 percent in rear differential plus 50 percent 600W. The STP is constantly being moved up by the transmission gears and the same action takes place in the differential with the ring gear.

I do not use STP in the engine as it all ends up in the bottom of the pan and there it stays !!! . A dragster mechanic told me the reason they use STP in their engine is because it is set up very loose, usually only make two runs and the engine is torn down and new oil and STP added ?


Just my opinion,


Ron

Re: Another question about oil viscosity
 

I use the 15/40 sold at TSC as most other Mod. A owners. 20/50 is airplane oil. For use with air-cooled engines with large clearances. My feelings are that you don't need it. The STP is, in addition to being a low friction additive, it clings. I'm told you cannot totally remove it with a solvent. It is useful in engines that may not be run for a while. It Helps prevent moisture rusting on the internal parts such as the cam and cylinder walls. I use a little MMO in the gas (not the oil) to help lubricate the valves.
Terry

Re: Another question about oil viscosity
 

"I do not use STP in the engine as it all ends up in the bottom of the pan and there it stays !!!"

Where does your oil pump suck from?

Re: Another question about oil viscosity
 

Enough already.... do you change your oil every 500 miles? Then cheap oil today is far better than anything in the day.


Oil filter: I run 1,500-2000 miles use a multi viscosity 15-40 works great for summer. Do not drive mine in the winter.


Use whatever makes you feel warm and fuzzy inside!


Remember Billions have been made selling "Snake Oils"

Re: Another question about oil viscosity
 

It's a good question about STP as the mains are only fed by gravity. I use it in modern engines when I get an oil leak or oil usage. Works wonders. However, these mains are pressure fed.

If others have used it and the engine hasn't seized up, then that's encouraging. The product has been around a long time.

I'd only use it if I knew the mains drain tubes were clear and the internal engine clean.

Re: Another question about oil viscosity
 

X2

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Re: Another question about oil viscosity
 

With that reasoning, then shouldn’t all the sludge in the pan be pumped through, and therefore no sludge.

Re: Another question about oil viscosity
 

15/40 is correct. Rotella fits the bill and more.

Re: Another question about oil viscosity
 

In other threads, some people who use STP in their transmissions have mentioned that it it is very difficult, if not impossible, to drain the stuff out of their transmissions.

If STP sticks to everything and cannot be removed without use of a solvent as has been mentioned in a post above, I would be concerned that it would clog the passage ways from the valve chamber so that oil would not flow very easily down to the mains, especially on startup of a cold engine.

David Serrano

Re: Another question about oil viscosity
 

When I've used STP in an engine I mix the STP with motor oil in a larger container with a paint stick before pouring it in my engine . STP oil treatment can mix with oil but I prefer mixing it before pouring it in my engine . Years ago I tried straight STP for gear oil . I didn't like the results Of STP for gear oil and went back to 600 w . I have also used 90-140 gear oil with good results . As for motor oil , it needs to be thin enough to flow by gravity to the mains in a cold engine . Another important consideration is that the oil needs enough viscosity to cushion the bearings . Ford recommended 20 weight for colder temperatures and 40 weight for summer use . I don't like to use any oil with less than 20 w for colder tempreatures for that reason .

Re: Another question about oil viscosity
 

I can only speak from our experience with using STP for over 40 years.

There should be no problem at all draining STP from transmission. Stop and think about this for a moment. You can pour it out of the bottle “right”. Pours slowly, like 600w oil would.

It does not clog passage ways. It only leaves a coating on metal parts as a cushion. If your only using one bottle, as directions state, that’s 15oz. Your car will have 144oz of oil to 15oz of STP. That is a little more than 10% STP. At oil change, you add the STP to a warmed up engine. It mixes completely with your engine oil. It will however change your oils viscosity, making it higher by ? depending on weight oil you are using.

It does not pool at the bottom of an engines oil pan. STP mixes completely with your oil.

Everyone has there own view on using any product. Some of us use it and like it, some call it shake oil. To each his own.

Re: Another question about oil viscosity
 

If you can get the STP out if the bottle you certainly can get it out of the drain plug.

OOPS! to slow in posting!