Multi viscosity or straight weight oil?

Fransisco

Fransisco

Filing Flight Plan
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Francisco McClain
I have an 85yr old pilot friend and AE that swears by straight weight oil. He is a wealth of information and very smart but I also have other friends that will only use multi viscosity weight oil. I just want what is best for the engine ... Any ideas ?

Also ,what is the frequency in which to change the oil in a lycoming 0-540....every 50 hrs?
 
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How often is it flown?
What time of year is it?
 
If you're aircraft/engine is approved for multi viscosity, and you park it outside for extended periods in very cold weather, I'd use multiple viscosity. The majority of engine wear takes place on start up, till the engine reaches operating temp. You need the engine oil to flow as best as possible when cold. That's what the multi viscosity does.
 
Shell W100 in a Texas based Mooney

No issues and very clean oil analysis
 
I made the switch to Phillips X/C 20/50 with camguard after reading about this ad nauseum.

I put about 150-200 hours/year on my hangar queen.
 
Engines can be
1. New (low hrs), operated often
2. New, operated infrequently
3. Old (high hrs), operated often
4. Old, operated infrequently
1,2,3 seem to do fine with Shell single weight regardless of summer or winter
4 seems to do better with Phillips multiweight regardless of summer or winter
 
Fransisco said:
I have an 85yr old pilot friend and AE that swears by straight weight oil.
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Many of our engines do not benefit from much of the additives in our multi weight and added chemicals.

The straight weight AD oil is all most engines really need.

Reduced weight, multi weight, only aid in cold starts, but claim to protect as heavier oils at high temps. I am unsure they do it as well.
 
Phillips X/C 20-50 with Camguard in my Mooney. Around 100 hours per year average and I change the oil/filter around 35 hours
 
Doesnt multi weight oil do better when it gets hot too? Im not really sure. Im in Colorado. Cold starts are a fact of life (down to 20F degrees for me although I have done it lower than that, maybe 10F). Multi is definitely better for that fact of life, IMO.

Thing is, straight weight or mulit, both will work. There's more than one way of doing things.

What do the manufacturers recommend? Isn't it either one?
 
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I have no recommendation as I'm just a dumb owner / pilot. I have been using aeroshell 100w for the few years I've owned. The only thing I've found is cranking the engine below 50dF is MUCH better after plugging in the preheater for about thirty minutes before cranking. Before then, the oil runs like molasses...
 
I learned many years ago that multi weight oils should not be used. It's like the saying. When something is made to do more then one thing it does neither very well.
 
Dr. O said:
Oil and religion
Two things not to be discussed in public
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Kinda, though I don't mind some oil talk at times.

Many of use get to beliefs on oil through 'convention'. It's the way we've always done it and it works for us, so we spread the news.

The truth is, there is more than one 'right' way to operate. I have at times used straight grade in the Summer, multi in the colder months. I currently mostly use multi grade year round.

6 of one, 1/2 a dozen of the other. Next.
 
I've used both...many times I'd run multi during the winter months and straight weight in the summer. I'm partial to straight weights though. The oil film stays up in the engine longer (thus protecting parts longer) between flights. This is somewhat less important though when using camguard, which I do. These days I'm in a heated hangar so I run W80 in the winter.

The other question the O.P. asked is how often to change the oil. I have a filter so I change mine every four months or 35 to 40 hours whichever comes first. Back when I was flying a lot for work, I'd occasionally go 50 hours in the summer. But I'd get there in six to eight weeks.
 
An oil thread? Isn't this "spin-zone" material? How about just going by what the manufacturer calls for?

Lycoming Specification 301F still applies, right?
 
I usually use straight weight Aeroshell +. But this winter 70 deg today, 30 tomorrow, 50 the next, 20 the day after. Due for a change, I' m thinking Phillips x/c 20-50 might be a good choice until spring.
 
I use Aeroshell 15W50 in my old A-65 and find that the oil temps stay a lot cooler with it than they do with any straight-weight, which tells me that the friction, and therefore the wear, is less.

A multigrade doesn't thicken as much when cold, so the pump finds it much easier to get it to the important bits when the engine is started. Bearings especially don't appreciate waiting for it.

In the flight school's airplanes I used 15W50 year-round and those engines all reached TBO without any hiccups and were still really tight when removed. Compressions in the high 70s and max oil pressures.

Multigrades aren't a mix of two straight-weights. A 15W50 is an SAE 15 oil with viscosity modifiers that clump together when their temperature rises and increase the effective viscosity of the oil, which means that they reduce the rate of viscosity decrease as the temp rises. A 15W50 will have the vicosity of a cold SAE 15 when cold and the viscosity of a hot SAE 50 when hot. I have shown students the differences between the various grades of hot and cold oils by leaving samples in the freezer overnight and immersing others in hot water for awhile. When pouring them, the viscosity changes are startling. A W100 will hardly move at -10°C, and your oil pump would have a hard time sucking it up from the sump. A W80 runs like water at 200°C. A multigrade displays a far narrower range of viscosity change.

Some folks resist this technology. It's too new or something? But we use computers to complain about it...

Viscosity2.jpg


oil03031907.gif
 
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Meh....year round, whether it needs it or not.....the Bonanza gets Phillips X/C 20-50 with Camguard.
 
If you're flying regularly (like 500-1k hrs a year) and you live in a temperate area (like so cal) just use straight weight.

If you don't fly much or fly in extreme temps go for something like X/C with cam guard.

If you fly frequently but in very cold conditions or very hot conditions use XC without cam guard.
 
There is very little discussion here about hot engine protection. Triva. Which oil protects better at 300f??? Multi weight or straight.....old school thought is straight weight WRONG! The viscosity modifiers in multi weight don't stop working at 212f/100c. They continue to slow the thinning of the oil compared to straight weight.

So if you over heat your engine a 20w-50 or 15w-50w will give more protection than a straight 50w!

Only real debatable benifit of straight weight oil is its abilty to cling longer to metal parts proving greater rust protection during infrequent use.

I'm surprised straight weight is still sold....


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James331 said:
If you're flying regularly (like 500-1k hrs a year) and you live in a temperate area (like so cal) just use straight weight.

If you don't fly much or fly in extreme temps go for something like X/C with cam guard.

If you fly frequently but in very cold conditions or very hot conditions use XC without cam guard.
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Would you mind explaining your reasoning behind that.

Aaronk25 said:
Which oil protects better at 300f???
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Do you know anyone who has actually done this? More importantly, do you know anyone who has done this and not changed their oil before flying again?
 
GlennAB1 said:
I'm thinking you want a full synthetic.
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Nope I don't want my oil anywhere near 300f. I guess what I was getting at is multi weight protects better at higher temps.

There isn't any auto mfg that still use straight weight cause it just doesn't offer the benefits of straight weight.


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timwinters said:
Would you mind explaining your reasoning behind that.







Do you know anyone who has actually done this? More importantly, do you know anyone who has done this and not changed their oil before flying again?
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Tim I don't know anyone who has done this or not changed their oil after doing so. Sorry if what I posted was misleading for you somehow.


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James331 said:
If you're flying regularly (like 500-1k hrs a year) and you live in a temperate area (like so cal) just use straight weight.

If you don't fly much or fly in extreme temps go for something like X/C with cam guard.

If you fly frequently but in very cold conditions or very hot conditions use XC without cam guard.
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why did you recommend "not" using Camguard?...was it the frequently or the temps?:confused:
 
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Checkout_my_Six said:
why did you recommend "not" using Camguard?...was it the frequently or the temps?:confused:
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Ya I like camguard, in fact Ed Collins was the one who told me first about how multi weight protect better. He actually asked a question to a group at a mooney summit and I answered wrong and said straight weight.




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What does the motor manufacturer recommend?
 
I used straight in the Gopher engine because that's what Lycoming said to put in it and my research showed there wasn't any real advantage the the multiweight in my situation. Ran 80 in the winter and 100 in the summer. I changed the oil more as there was no filter.

Now that I have the Continental, I put the multigrade in because that's what Continental says and it works across the temperature ranges I fly.
 
Lycoming 0-320 - any temperature - 15W-50

Aeroshell or Phillips 15-W-50 is what she gets.
 
tinerj said:
Engines can be

1. New (low hrs), operated often

2. New, operated infrequently

3. Old (high hrs), operated often

4. Old, operated infrequently

1,2,3 seem to do fine with Shell single weight regardless of summer or winter

4 seems to do better with Phillips multiweight regardless of summer or winter
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Out of curiosity, what is your basis for that?

I find that number 4 seems to benefit the most from straight weight oil and the reason is this: as the engine gets more hours on it, the cross hatching on the cylinders wears down/smooths out and multi-weight oil does not cling as well over time as straight weight does.

A higher time engine that doesn't get regular use/sits for extended periods, particularly in humid environments will be more susceptible to corrosion with a multi-weight oil.
 
Checkout_my_Six said:
why did you recommend "not" using Camguard?...was it the frequently or the temps?:confused:
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Because if you're flying frequently, changing out your oil often and your plane isn't sitting, IMHO you're not getting that much bang for your buck with the cam guard.

For me, with a plane that flys in a decent range of temperatures and will sit for a month at a time on occasion. Cam guard all the way.

For a flight school plane which is getting flown daily, I just couldn't justify the need or expense, just use straight weight if you can get away with it climate wise, or use X/C if you're living in the tundra like me.
 
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