How many use SAE 30 motor oil??

[Mill KNOB]

I have in my fine little bronco a 170 6 cycle that runs little a little sewing machine. Since I have bought it from the original owner I have changed the oil with a different weight of oil that the last owner hadn't used in the bronco. He told me that he had always used 30 HD motor oil. I used 10w-30 on my last oil change and was woundering if I should go back to the 30 HD oil? It seems like it was not a noisy rattling motor when it had the 30 HD oil. It's time to change the oil and wanted some input on which one would be the best to go back with or if it matters?

 

[bronconut73]

Maybe multi viscosity in the winter and simple 30 weight in the summer.

 

[blubuckaroo]

It depends on your use.
The 10W part of the oil spec means winter. It is designed to let the oil flow better until the engine gets warmed up. Once the engine is up to temperature, your SAE 30 should be about the same.
That's what the oil engineers designed it for, but as you've noticed, it was quieter with the SAE 30. I'm no oil engineer, but 10W-30 looks a lot thinner than SAE 30 when warmed up.
If I were you, I'd split the difference and use 15W-40 Diesel rated oil like Delo 400 or Rotella. Those have a SF rating for your gasoline engine.

BTW, I absolutely love that sewing machine sound from a good running straight six.

 

[Timmy390]

15W-40 Rotella in my rig

Tim

 

[Mill KNOB]

It depends on your use.
The 10W part of the oil spec means winter. It is designed to let the oil flow better until the engine gets warmed up. Once the engine is up to temperature, your SAE 30 should be about the same.
That's what the oil engineers designed it for, but as you've noticed, it was quieter with the SAE 30. I'm no oil engineer, but 10W-30 looks a lot thinner than SAE 30 when warmed up.
If I were you, I'd split the difference and use 15W-40 Diesel rated oil like Delo 400 or Rotella. Those have a SF rating for your gasoline engine.

BTW, I absolutely love that sewing machine sound from a good running straight six.

Wow. Good info. I love the sewing machine sounds too.

 

[Mill KNOB]

15W-40 Rotella in my rig

Tim

Tim, is that weight a thicker oil? Thanks for your input.

 

[Timmy390]

Tim, is that weight a thicker oil? Thanks for your input.

Thicker in summer thinner in winter than SAE 30

It gets hot here in AR in the summer. I like a thicker oil when it's that hot. 10W-30 gets as thin as water. That's OK for newer cars and trucks due to really tight tolerances but not for the older builds and rebuilds. It gets cold here from time to time (18 degrees the other day) so I like something designed for winter too hence the 15W. Thicker oil seems to quiet the valve train a bit too (if you have any noise).

Diesel oils tend to have more zinc in them. While I'm not running a flat tappet cam, I still like the idea. Also, I run 15W-40 in my 2500HD Duramax so always some sitting around if needed.

I did use 30 HD oil for my last cam breakin. Engine builder suggested it.....

Tim

 

[TheGanzman]

I run straight 30 weight year 'round; of course, I live in San Clemente CA, where it was a blustery 68 degrees yesterday...;D

 

[76YETI]

15w-40 Rotella

 

[Broncobowsher]

Another internet oil thread...

Well back to the oils. Another factor is engine wear. When an engine is fresh and tight a pretty thin oil is all that is needed to float the crank on the bearings. But as engines wear that thin oil flows out of the wider clearances a lot easier. By going to a heavier oil it stays in the bearing a lot better. So an engine could use a 5W30 when it is new, age into a 15W40, and limp into retirement on 20W50. All of which would be correct oils for the same engine depending on what part of life it is in.

Add in oil technology has improved a lot in the past 50 years, but that doesn't mean it lasts any longer since it still gets loaded with the same contamination as the oil oils. Carburetors are not friendly to motor oil.

 

[bigcountry]

I use 15w40 rotella in my broncos and my older trucks. I ran it in the 67 bronco six cylinder I had as well.

and of course my diesel.

 

[Mill KNOB]

Thanks everyone for there input and feed back. Looks like I will be putting 15-40 in the ole girl.

 

[bronconut73]

Thanks everyone for there input and feed back. Looks like I will be putting 15-40 in the ole girl.

Not just 15-40.
Rotella 15-40

 

[ntsqd]

Unlike in the past, they're all "LE" formulations these days (low ZDDP), so choose the brand you like the most and use that. I use Delo 15w-40. And the sum end of all oil threads is bobistheoilguy.com

& btw multi-grade oils only act like they're the heavier listed grade when hot, they don't actually convert or change to the heavier grade. They're still 15w or 10w or whatever oil. Making the oil do that is some trick chemistry that breaks down with age & heat cycles.

 

[Pa PITT]

... Wow I too like Rotella 15W40... But I'm a diesel guy... But before I put the 4BT in my Bronco I ran Rotella in my gas Bronco .
.. So on my farm I HAVE 4 Tractors on Rotella . My Dodge Diesel truck .. My Diesel Bronco ..& my 1980 300 CID BRONCO... & MY JEEP ZJ 4.0L...
... My wifes Durango is 0w20. It turns on the check engine light with anything other than that. Don't ask me how I know that. ''Yes For Real..''
.......... Now what I wanted to say .. I drove an old 87 Bronco II..2.9 V6... It had about 140k on it when I bought it. I gave $500.00. for it when I bought it ..A Battery & a set of tires. & a fuel regulator on it ... I had to furnish my own vehicle...I was a PR Rep for a corporation for about 6 years . I went & talked to their customers ..Great Job. Until 9/11/01
... That V6 RATTLED crazy bad if I didn't put 1/2 a bottle of Lucus in it at each oil change. In order to save money on each oil change I figured out if it had a pint of Lucus in it it didn't rattle .. & I changed the oil every 5,000 miles. I ran it to 387K THEN I sold it . For $1500.00...

 

[56f100bbw]

Does Rottella 15-40 still have zinc in it

 

[bronconut73]

Does Rottella 15-40 still have zinc in it

I have heard it has plenty of it Bud. Enough that you do not want to use it in a vehicle with a gas catylitic converter, I'm told.

But you can buy zinc in a bottle at the parts store if you want more.

 

[ntsqd]

I have heard it has plenty of it Bud. Enough that you do not want to use it in a vehicle with a gas catylitic converter, I'm told.

Do you have any documentation of that? I tried to search it qwikly, and it's obvious I'm going to have to dig deeper. Which means not while just starting work. In that search I did find this which makes me question the "common knowledge": http://www.nonlintec.com/sprite/oils_and_zddp.pdf

 

[Timmy390]

Do you have any documentation of that? I tried to search it qwikly, and it's obvious I'm going to have to dig deeper. Which means not while just starting work. In that search I did find this which makes me question the "common knowledge": http://www.nonlintec.com/sprite/oils_and_zddp.pdf

From the Shell Rotella WiKi

(The 15W-40 Rotella T with Triple Protection oil has approximately 1200 ppm of zinc and 1100 ppm phosphorus at the time of manufacture.)

https://en.wikipedia.org/wiki/Shell_Rotella_T

Tim

 

[ntsqd]

Well, since I can edit that page to say what I want it to say you'll have to forgive me if I don't take it to mean much. How about a Shell.com page that lists the ZDDP content?

And, given the pdf that I linked along with some of the other reading that I've done on the topic I am not convinced that ZDDP content is the exclusive indicator of anti-scuff properties in any oil. As the pdf points out, it just would not make sense for oil mfg's to make an oil that isn't backwards compatible and creates problems for them. Nor does it make sense that the API would come up with a spec that isn't backwards compatible.

We've all heard of cams that went flat with the new oil(s), but can anyone point to a specific flat cam that was proven to be specifically the fault of the "new" oil and not some other combination of factors? I know that I can't.