Here in So. Cal. Where temperature hardly ever gets below 50 degrees would 20w/50w motor oil be OK? Now I know oil has been beaten to death here and a lot is personal preference. But the question is, "Would 20w/50w do any harm to engine?"

 

1964 with a 292 automatic

 

It shouldnt do any harm, a lot of guys run 20/50. I think 10/40 would be better, but that is just me. I run 10/30, Valvoline VR-1 racing oil, with full complement of ZDDP. If the engine is very worn and oil pressure is an issue, the higher viscosity may be a help.

 

You are right: discussions of motor oil choice on a car-related forum are worse than bringing up politics or religion. Usually discussions of religion and politics are conducted with more facts and gentlemanly behavior, too.

I agree with 46yblock. Here in Texas, it gets pretty hot in the summer. My problem with thick oil is that it does a poor job of flowing when first starting up. You'll get plenty of oil pressure, but most of the oil the pump is pumping is going out the bypass, rather than thru the bearings, which is where you want it.

I use straight 30 in the summer time; it keeps oil pressure better on a hot day when the engine is hot than does 10W-40. During the cooler weather, I run 10W-40, so it will flow better during startup.

The crank and rods of my Harley run on roller bearings and oil flows differently in a roller bearing engine than in a plain bearing engine. But these engines really get hot on a hot day. I used to use straight 50 aircraft oil until I got hold of Phillips Trop-arctic 20W-50. That oil was heaven sent, as starting a 4 1/2" stroke Harley on a cold day is a formidable chore, even with a fat boy like me hopping on the pedal.

My point regarding the semi-related motorcycle story has to do with the effort needed to start a motor. This is something that's not readily apparent unless you yourself are furnishing the turning power to start. Think about your needs and make an informed decision, and you'll be OK.

 

With the viscosity specs changing every 10 years, I would recommend 5-30....if you find you're using a little oil then jump up to 5 or 10-40. 50w is a little heavy in any engine (unless we are talking high reving imports).

 

Oil wars have been kept at bay on this thread, thankfully. But I have a question. Given the good number of Y owners, and perhaps FE owners, who run 20-50, what is there in the engine design that warrants the high weight oil? ZDDP wouldnt be an answer because it can be had in lower weight oils and/or additives. In my mind there are some good reasons for running lighter oils, but I cant think of any for running heavier.
Just curious.

 

Heavier oils generaly offer more pressure and a greater resistance to displacement. So you tend to have a better film on the bering that is less likely to "squeeze" out when a con rod slams into the oil film. They also do not become less viscous as the temperature rises protecting engine surfaces further. This is why diesels use 20-50 and 350s use 10-30.

Using a 20-50 in a hot climate will be fine. It is 20 weight oil that guards like a 50. So it would pump like old straight 20.
The advantage to using a 10-30 or 5-30 is it is thinner and protects equivalently to the second number. Therin reducing power loss due to windage and pumping a stiffer oil. A 5-30 is a 5W oil that gaurds like a 30W.

 

"Heavier oils generaly offer more pressure and a greater resistance to displacement. So you tend to have a better film on the bearing that is less likely to "squeeze" out when a con rod slams into the oil film."

I had wondered if something like that was an advantage of the 20W50. Still, does the old Y design particularly prefer this degree of protection? I wonder what would happen if 20-50 were used in the little V-6 in my Ranger. It would probably fall on its face.

 

Some newer engines have tighter oil clearences and dont like the thick old oils. Volkswagen now uses a 0-20W if I remember correctly.
I use 10-30 rotella in the winter and 15-40 rotella in the summer. This goes for my 300, 292 and the old ladys 5.0.

I belive the 10-30 stuff is a bit stiff at -40 but otherwise it performs flawlessly.
A worn engine genearaly likes a stiff oil as it gives cheep compression and smooths out the clinks and clangs of worn parts.

 

One of the aspects to the oil discussions that have made this such a caustic subject with respect to Y Blocks is the idea that Y Blocks require a different kind of oil simply because they are Y Blocks.

Personally, I reject that notion.

It is true that a Y Block may get dirty internally because of the shortcomings of its factory PCV system. In that case, it is just like any other engine that is internally dirty regarding the choice of oil.

It is true that a Y Block may require a different kind of oil due to it having large clearances -- a condition resulting from a lot of wear or from the way the machining was done when it was rebuilt. In that case, the correct oil for it would be the same as for any other engine having large clearances.

I would caution folks not to get caught up in the hype of their own Y Block mystique or that of others and feel that some supernatural properties are at play with Y Blocks that pertain to no other engine. It is unique enough and interesting enough the way it is, without turning it into some kind of jackalope or yeti beast (tho for non-Y tenderfoots, such tales can be amusing...).

 

Wild Bunch I will agree. My reasons for using a oil like rotella is due to mechanical lifters.
However I would see no ligitamate issue in using a 5-30W full synthetic as long as one used a ZDDP additive for the mechanical lifters. Buy a reputable oil and add ZDDP if neccisary and you will be ok. 5-30 would be fine in a ND winter. I would use at least a 10-30W in the summer, prefferably a 15-40W. The oil clearances are due to 50s machining tech. Not due to some special Y neccisity. ZDDP is about the only need in their oil.

 

My owners manual calls for 20 or 20w oil I just planned on running 10w30 in my 292. I mean I run it in all my other vehicles and theres no problems. Its just something I run and something im comfortable with. Personally I say 40 or 50 weight is too heavy for a engine that is in good to great condition but thats just me.

I will how ever agree make sure you have good ZDDP to prevent wear. Other than that weight of oil is up to the owner I guess. Lower weight oil will give you a boost in economy as well as a boost in oil getting everywheres quickly on cold start ups.

One thing I try to do though and this is just me, I try to run what the factory calls for. I got a line on Type A transmission fluid cause thats what the transmission calls for. So I would trust the owners manual since its written by the designers/builders of the car.

 

I contacted lucas oil. None of their products contain ZDDP.
I have E-mailed rotella and am waiting for a reply.
So far the only additive I can find that has ZDDP is the goodwrnch additive.

 

I contacted comp cams while back and they told me their cam break in oil which has zddp in it is safe to use in both convential and synthetic oil and you can use it with every oil change. Its not one of those type you have to run for 500 miles then drain it you can go 3,000 miles (or 2,000 miles if you want to follow the 50`s oil change interval)

Theres also another one out that is pure ZDDP additive for flat tappet cars that you just add but I dont know much about that.

 

Valvoline VR-1 Racing oil has ZDDP in the proper amounts and can be used with or without additives.

According to their site info VR-1 racing oil has 75% more zinc than regular SM oil, .13% zinc and .12% Phosphorous, in each of their viscosity grades. Their "Not Street Legal" racing oil has even slightly more, .14% zinc and .13% phorphorous. I havent seen the not street legal oil for sale locally, but can buy the VR-1 racing over the counter at NAPA. Price is around $4.80 per quart.

The Comp Cams additive is supposed to be excellent. After cam breakin I expect a person could take an oil similar to the Valvoline, add an ounce or two of the additive to bump up the protection a little higher and save a fair amount of money on each oil change. However for most of us this may still be a waste of money. The Valvoline tech line answered a guys question regarding ZDDP, and in the response said that a stock flat tappet cam with stock spring pressures should require 800 ppm zinc and 730 ppm phosphorous. So the 1300/1200 ppm found in VR-1 would be fine with no additives.