Does anyone know anything about oil viscosity for a stock flattie. I have just changed the oil in the old girl. Guy at the store recommended a standard 20/50 weight oil which he says is good for all old or worn engines ( I think his idea of an old engine is anything prior to 1985 judging by the way it looked like he still hadn't started shaving yet). The old oil came out thick as treacle and blacker than tar (no doubt just the way these old beasts love it). The motor seems perfectly happy with the new oil, which has been in there for a couple weeks now, but when up to normal operating temperature, the oil feels a little light. Oil guage isn't working right now so I've no idea what sort of pressure it's running. Anyone know anything about adding a viscosity increaser such as Mooreys or similar so as to cushion those bearings etc a little more?
Oil additives (viscosity increasers)
- Thread starter 66miles
- Start date
Mart
Well-known member
Use the 20-50.
If the old oil was thick, it might mean the engine has a lot of sludge in it. You might need to use a non detergent oil.
Having the oil thicker than necessary robs power.
Many will recommend thinner oil than the 20W50.
I have used 20W50 in the past and more recently 15W40.
It's all good.
Mart.
If the old oil was thick, it might mean the engine has a lot of sludge in it. You might need to use a non detergent oil.
Having the oil thicker than necessary robs power.
Many will recommend thinner oil than the 20W50.
I have used 20W50 in the past and more recently 15W40.
It's all good.
Mart.
change the oil every 1000 miles, the tolerances are not nearly as close as modern engines and they do tend to sludge (carbon) up. 20W50 is perfect, in the states this oil has the ZDDP which is the zinc compound for the valves and get the gauge fixed or add a working one to the engine
Did you ever drink a milkshake thru a straw(lot of pressure little liquid),drink water with a straw, low pressure lots of liquid,your oil at temp is thin moving thru the engine keeping it happy,don,t make it thick to slow it down.Just think how thick your oil is at startup,high oil pressure and slow moving oil! I myself would like thin oil at startup so it flow quickly to all moving parts. all oil is has the same flow at 212 degrees. Pete http://ferrarichat.com/forum/faq.php?faq=haas_articles
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FortyNiner
Well-known member
1937pickup
Well-known member
STP-didn't have sucrose in it? Not fun stuff to deal with when taking an engine apart that used STP. PRPMMP posted a link that I read a while ago that changed my thinking about oil viscosity.
Pete
BANNED
These engines will run fine with just about any kind of oil you can put in them, even straight CARBON TETRACHLORIDE (CcL4) works until it evaporates.
By the way cmbrucew I knew Gus Justice well. He used to come up here quite often.
Just fitted a new oil pressure guage. Removed the old sender which I need to test as I have a hunch its not working right. The new guage just screws straight in where the old sender came out and uses an oil feed line straight to the guage (no electrics and no guesswork). Pressures as follows: Cold normal idle 30PSI. Cold fast idle 40PSI. Hot normal idle 15PSI. Hot mid-rev range 18-19PSI. Do these numbers look normal? I know the stock pumps ran pretty low pressure. Also there appear to be 2 separate oil galley outlets at the back of the bell-housing. One of them is plugged off. The higher-up one has the oil pressure sender in it. Anyone know what the other one might be used for?
stp was suppose to be the thing when it came out. I stopped using it a long time ago. I to use 20/50. what ever you do change the oil often.
personely I probably would use detergent oil eventualy. do you have an oil filter? true they do a poor job but better than nothing. the older I get. the better I was!
personely I probably would use detergent oil eventualy. do you have an oil filter? true they do a poor job but better than nothing. the older I get. the better I was!
rotorwrench
Well-known member
When new, the flathead V8 used SAE 20W20 or SAE 30 engine oil depending on winter or summer operation. Now days it would be more like SAE 10W/30 on an overhauled engine for year round operation. An old loose motor would like more viscosity to keep the pressure up.
Any oil is better than none. Non detergent is for break in so that there are no friction modifiers but a person shouldn't run it more than 500 miles or so before switching to detergent oil. If a person doesn't know the history of the engine, they should start out with frequent oil changes with detergent oil whether there is a filter or not. Oil is cheep compared to an overhaul with a ruined crankshaft. Drain engine oil imediately after a complete warm up so the oil can carry all the crap out before it settles to the bottom again.
Studebaker Technical Products (STP) viscosity buillder was for worn & loose engines. It also works well mixed with regular oil as a build up lubricant at overhaul. It keeps the lubricant on the parts longer prior to start up. Other than that, I would have no use for it. It's too much like molasses in texture and takes forever to get it in or out of a gearbox.
Any oil is better than none. Non detergent is for break in so that there are no friction modifiers but a person shouldn't run it more than 500 miles or so before switching to detergent oil. If a person doesn't know the history of the engine, they should start out with frequent oil changes with detergent oil whether there is a filter or not. Oil is cheep compared to an overhaul with a ruined crankshaft. Drain engine oil imediately after a complete warm up so the oil can carry all the crap out before it settles to the bottom again.
Studebaker Technical Products (STP) viscosity buillder was for worn & loose engines. It also works well mixed with regular oil as a build up lubricant at overhaul. It keeps the lubricant on the parts longer prior to start up. Other than that, I would have no use for it. It's too much like molasses in texture and takes forever to get it in or out of a gearbox.
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