Advantages of straight weight oil

Status
Not open for further replies.

Now

Joined
Mar 20, 2014
Messages
10
Location
Alabama
New member first post. I've been working in the industrial field since 1980 and was greasing cars and trucks since age 13 using the old huge single cylinder lift.
I did do a search.

Topic should read disadvantages of multi weight oil. What qualities does the oil forfeit to become multi-weight?

I know about cold starting and flow capability of multi-weight. I always allow my engines to warm up, before raw-hiding them.

Any links welcome.
 
Since straight weight oil doesn't have Viscosity Improvers, it will not sheer as readily.

However, the advantage of having a lower viscosity at start-up outweighs this factor, which is why multi grade oils are recommended for all modern light-duty engines. Multi-grade also has the benefit of better detergent development; that is, Pennzoil and Mobil 1's detergents are not seen in any single grade oils.

Simply put, multi grade oil carries many performance improvements that makes it the superior oil.
 
if the multigrade oil has no,a small amount of , or high quality VII then then there is really no advantage to single grade motor oils in most applications.
 
Even the straight grades aren't really straight.
The basestock will have its own VI, so even a straight grade will be thinner at cold start than it's SAE viscosity grade might lead you to think.
In your climate, you could probably run a 20W-20 winters and a 30 in summers with no ill effects in most engines.
There was a member here some years ago who ran an Amsoil straight 30 syn in a modern car (It was the old FWD 300M IIRC) with good results and we have at least one other member who ran 30 grade Delo for some time because he got it really cheap on clearance. He had good results as well.
I've sometimes thought that a few runs of a straight grade in a beater followed with a UOA might be very entertaining.
Want to try it?
 
Been running Delo 400 straight 30 in the GMC in my sig since AZ blew it out for 99 cents/gallon-other than not being able to start it unplugged this winter one morning (-15 degrees F.), no problems.
 
Ahh, the good old Delo SAE30 days. I'm down to two gallons!


I started both diesel and gas engines below freezing. I didn't notice any change in cranking time.
 
In the 50s and early 60s that is all we had,,,never lost an engine in Tennessee over it,,,go figure.
 
I have:

1) Mixed 30 with 10-30 in varying amounts
2) Ran straight 30
3) Even ran straight 40 (Im in TX summer and oil was almost free)

My 1997 Chevy truck never...even...noticed.
 
In an engine that is run for very long times, essentially steady-state, I dont see a reason to use anything different. Uses like that might be boats or cross-country applications like greyhound busses.

IMO the shear-stability and better flow of a multigrade makes it the better option, these days at least. In some places with high continuous ambient conditions, it still may be the best.

If I truly drove non stop a lot, and could find a good monograde, I suspect it might be an interesting application. Perhaps ditto if I were driving a police car or taxi. For anything else? Not sure unless it was really needed for some other reason, and you didnt want to go syn.

Here is an interesting little thread I had a few years ago about MB's design considerations for monogrades:

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2325682&page=all
 
Originally Posted By: Zaedock
Ahh, the good old Delo SAE30 days. I'm down to two gallons!
I started both diesel and gas engines below freezing. I didn't notice any change in cranking time.


Do you think it lubricates as well as a 0W in the first 10 minutes after startup below freezing?


Originally Posted By: gfh77665
I have:
1) Mixed 30 with 10-30 in varying amounts
2) Ran straight 30
3) Even ran straight 40 (Im in TX summer and oil was almost free)

My 1997 Chevy truck never...even...noticed.


I don't mean to single you out...

Why do you think it was free? We keep hearing things like "my engine likes it" or "my engine doesn't like it". There are all kinds of placebo effects going on here.

We could drain all the oil out of our engines and they'd start right up and run well for some time. Is that a like or dislike?
 
Briggs And Stratton and Tecumseh engines often recommend using SAE30, and in extreme cold, multigrade syn is recommended.

Yes, there is Amsoil SAE30. It got the name because much like other SAE30 oils, there are no VIIs. However, since PAO basestocks already have a great viscosity index, some people have compared the oil to a 10w30.

A while ago, I did some research on the 1970s Pontiac 301 turbo engine. It called for SAE30 in all temperatures, and some people have said that the multi-viscosity oils would have a higher NOACK, and with the added heat of a turbo, that could be a huge problem.

Another reason SAE30 has an advantage over multigrade oil is that the API does not limit SAPS content the way it does in multigrade oils. That in mind, you would need to do a VOA to actually know if it is a high SAPS oil.
 
Originally Posted By: JHZR2
In an engine that is run for very long times, essentially steady-state, I dont see a reason to use anything different.


Also without the temporary shear of VIIs (I believe that) you can run thinner straight weight KV100s than multis...

As an example, this makes sense...moreso to me than a 0W-20 in a 10W-30 application.

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1174209
 
Originally Posted By: turtlevette
Originally Posted By: Zaedock
Ahh, the good old Delo SAE30 days. I'm down to two gallons!
I started both diesel and gas engines below freezing. I didn't notice any change in cranking time.


Do you think it lubricates as well as a 0W in the first 10 minutes after startup below freezing?


Do you think that someone who doesn't ever SEE freezing needs any more than SAE30's cold properties ?
 
Originally Posted By: turtlevette
Why do you think it was free? We keep hearing things like "my engine likes it" or "my engine doesn't like it". There are all kinds of placebo effects going on here.


No placebo effect here, I am referring to the clearance price I bought it out at. I bought 200+ qts for less that $150, when some convenience stores were closing out. Most all of it was Mobil 5000 or PYB.

The majority was 5-30 and 10-30, but it did include about 15-20 30's and 40's.

I use the multigrades in the winter, and use up the straight weights in the TX summer.
 
turtlevette seems to have a misunderstanding of the "placebo" effect, thinking that the "placebo" effect is imagination, when it is actual, clinical changes, brought about by something that shouldn't have brought such changes.
 
Originally Posted By: turtlevette
Originally Posted By: Zaedock
Ahh, the good old Delo SAE30 days. I'm down to two gallons!
I started both diesel and gas engines below freezing. I didn't notice any change in cranking time.


Do you think it lubricates as well as a 0W in the first 10 minutes after startup below freezing?



Yep. It did a fine job too.

There is more to start up wear than oil flow. Delo SAE30 has a pour point of -24*F and behaves more like a 15W30.

10 minutes? Is it ideal, no - but nothing is going to blow up.
 
Originally Posted By: Shannow
Originally Posted By: turtlevette
Originally Posted By: Zaedock
Ahh, the good old Delo SAE30 days. I'm down to two gallons!
I started both diesel and gas engines below freezing. I didn't notice any change in cranking time.


Do you think it lubricates as well as a 0W in the first 10 minutes after startup below freezing?


Do you think that someone who doesn't ever SEE freezing needs any more than SAE30's cold properties ?


Yes. Absolutely.

I think I see a pattern here. You have different "fan clubs" here. Thick oil, thin oil, and no/low VIIs. There's really no changing of anyone's mind that's going to happen.
 
No, please explain how oil that's flowing in seconds is going to protect more than oil that's flowing in seconds...I'm interested.
 
Originally Posted By: Shannow
No, please explain how oil that's flowing in seconds is going to protect more than oil that's flowing in seconds...I'm interested.


Unless the oil is in its viscosity sweet spot its in its "plastic" state and does not lubricate as well.

Also, do you think oil in a syrup like state is going to sling properly to lubricate the piston and rings?

Hello?
 
Status
Not open for further replies.
Back
Top