Hey, we haven't had a good oil war in a while...

[TR 1]

I pony up for the Amsoil in the GMC as well, FWTW... As mentioned above, the newer formulations seem to always be changing, and I don't always have the time to follow which is the "go to" oil now for older vehicles. But I've never really heard a bad thing about any Amsoil product outside of the cost. I do stick with M1 or QS synthetic for my newer cars, though. Whichever I can find on sale at Wallyworld. No need to spend Amsoil $$ on these.... New cars do great on new formulations of oil.

One thing that helps is you can sign up for their "Preferred" program... It's good for one year, and it drops the price around 20%. Amsoil also offers discounts on higher quantities, so I will pay for the preferred, then stock up for a few years.. I won't renew the preferred program again until I need more oil.

As to the Z-Rod, I think what makes it a hot rod oil is that has corrosion inhibitors to help while a car is stored for extended periods... They also have a non-collector car, high zinc oil as well that is a little cheaper:

https://www.amsoil.com/p/amsoil-premium-protection-20w-50-100-synthetic-motor-oil-aro/?srsltid=AfmBOop8F4rjJLP4STlvOKJKeD1U70XCsaNDlaHcNEWceG1by9nibIp0&code=ARO1G-EA

You can buy this oil by the case in gallon sizes, which also helps with the cost. I throw in a quart or 2 of the z-rod, then finish out my fill with this oil for the GMC.

By the way, I've had excellent luck with Amsoil ATF... I run it in any of my cars that have an automatic (Including the GMC). We have a G8 we bought new back in 09, and it is still running the original transmission with 325K on the clock. (and counting) We put over 200K on an MDX from the early 2000s, and the Honda transmissions in those cars were terrible. Never had a problem with the gearbox. Actually, thinking back, I've never had an automatic trans go out on a car I've had running their ATF...

 

[TR 1]

Another good option I saw mentioned above is Valvoline VR1... They recently started carrying it at Walmart as well. It is marketed as a "Racing" oil, so not sure what level of detergents are in it. The "Racing" thing may be all marketing, or maybe it lets them run afoul of the newer, low zinc formulation requirements... Similar to HD oil. Not really sure, but I do run VR1 in some other old cars I have, and have had good luck with it as well.

Main reason I spring for the Amsoil over the VR1 in the GMC, is because I tow a jeep here in Texas... And I often tow in the summer as well. The Amsoil does better with the heat, in the research I've seen.

I've used the diesel oils as well, but tend to only use them in diesels, or in some of the old Mazda rotaries I've had. Always been a solid performer amongst other oils out therein those apps, but have not looked into what makes them into a "Diesel" oil, and less suitable for gas
.

 

[Christo]

What the video did not address is the fact that our engines are normally-aspirated carburetorated engines that produce soot. Not the fuel injection engines he’s discussing. So the relative advantage of the T4 seems a better choice. Doesn’t that play into it?

I haven't found a Motor Oil Geek video yet that makes a distinction between carbureted and fuel-injected engines, but I did find this:

At the 44 minute mark he gets into a specific question about diesel oils like T6 in gas engines. He says he's not a fan of using diesel-only oils in gas engines, but he then goes on to say that any oil that has an ACEA approval is formulated for both diesel AND gas engines, and guess what: Rotella T4 is ACEA approved:

www.shell-livedocs.com/data/published/en/5e129bc2-8941-43f1-81c8-0c6345b45e33.pdf

So, it looks like there's little downside to using Rotella. Nevertheless, based on the Motor Oil Geek videos I'm going to try full synthetic and see what difference there is in the oil analysis results. I'm leaning toward NAPA 10W30 full synthetic. Motor Oil Geek says it's made by Valvoline and has higher moly/MODTC in it and he likes it quite a bit. Rotella T6 would of course be another option.

 

[Richard RV]

I've been using Rotella T4

Flat tappet cams, ZDDP and all that.

Before I bought my first GMC I had exactly zero automotive experience, I'd never changed oil or a spark plug. I've been playing catch-up ball. Not infrequently I would follow the opinion of a more experienced GMCer, one of the gurus.

Is the gotta-use-ZDDP-in-a-flat-tappet-engine dogma real world science or community general consensus?

Blackstone Labs is the household name in oil testing. Here's their article about running an engine without ZDDP.

ZDDWhat? | Blackstone Laboratories

How important is ZDDP in flat-tappet engines? Blackstone does an experiment to find out.

www.blackstone-labs.com

An extremely small sample size, but he's Blackstone's lab manager, mechanical engineer, pilot, etc.,

Ryan Stark | Blackstone Laboratories

Ryan started at Blackstone in 1997 after graduating from Purdue University with a degree in mechanical engineering. Ryan is responsible for writing and maintaining Blackstone's software program, setting up and managing the lab, writing reports, and a million other things that need to be done in...

www.blackstone-labs.com

The article is posted on Blackstone's web site, so it's pretty much their stance on the matter.

Is the ZDDP tide changing?

 

[Christo]

Before I bought my first GMC I had exactly zero automotive experience, I'd never changed oil or a spark plug. I've been playing catch-up ball. Not infrequently I would follow the opinion of a more experienced GMCer, one of the gurus.

Is the gotta-use-ZDDP-in-a-flat-tappet-engine dogma real world science or community general consensus?

Blackstone Labs is the household name in oil testing. Here's their article about running an engine without ZDDP.

ZDDWhat? | Blackstone Laboratories

How important is ZDDP in flat-tappet engines? Blackstone does an experiment to find out.

www.blackstone-labs.com

An extremely small sample size, but he's Blackstone's lab manager, mechanical engineer, pilot, etc.,

Ryan Stark | Blackstone Laboratories

Ryan started at Blackstone in 1997 after graduating from Purdue University with a degree in mechanical engineering. Ryan is responsible for writing and maintaining Blackstone's software program, setting up and managing the lab, writing reports, and a million other things that need to be done in...

www.blackstone-labs.com

The article is posted on Blackstone's web site, so it's pretty much their stance on the matter.

Is the ZDDP tide changing?

The Motor Oil Geek just released a video about this very topic. Says it better than I could, with science!

 

[Tom Katzenberger]

Out standing video! Now what are we going to fight about? LOL.

Basically all new oils are good for flat tappet engines. Pick a good oil and role with it.

I think with as little as we use our coaches we can just change the oil a couple times a year and do well.

I am also waiting for the "Oil Geeks" next video where he does the comparison using Mobile1 Classic 10w-30 against the others. That should be the final nail in the coffin.

Take care,
All

 

[Tom Katzenberger]

Same subject another note: I think this is what Larry was saying all along. New oils have replacement additives in lieu of Zink.

Again, every one take care and stay healthy.
Tom K.

 

[mech0001]

I'm going to be running Delo 400 XLE which is 15w40 partial synthetic. They also make an all synthetic version, I think, labeled with an S. Anyway, it's the zinc and the other detergents. For these oils it will be concentrated with those items that Diesels most need. I believe sulfur suspension is one of those things and perhaps the acidity of a diesel's oil will be different. I don't think those detergent choices will adversely affect my motor's health with frequent oil changes.

That being the frequency of oil change is always a factor. You don't need a fantastic detergent or absorption profile nearly as much when you adopt a 3ooo mile oil change regimen. Also, I'm not going to buy into that thicker oil doesn't give better protection line. I fed my last motor Quaker State 10w30 synthetic and it ate it's crank. Ok, somebody likely put it together wrong and sorry I'm gun shy now!

 

[jampants]

Thought I'd tag onto this thread and see if @Christo if you'd decided on oil for your new rebuild yet?

I'm just reaching the end of the break in miles on my S&J 455 rebuild (to Jims spec) so was re-looking at these threads for which oil to go with now.

In my old engine before it bit the dust I was using Valvoline VR1 20W-50. Oil pressure seemed a bit low at times so I went with this slightly thicker oil.

Am now thinking about 10W-40 or 10W-30 options as oil pressure even during breakin period has been soild 60psi according to the dash gauge - with new pressure sender. S&J recommend no fully synthetics for first 4500 miles.

Watched the Oil Videos linked - still not really sure what to use.

Any other recent rebuilds care to share what you used?

 

[Christo]

Thought I'd tag onto this thread and see if @Christo if you'd decided on oil for your new rebuild yet?

I'm just reaching the end of the break in miles on my S&J 455 rebuild (to Jims spec) so was re-looking at these threads for which oil to go with now.

In my old engine before it bit the dust I was using Valvoline VR1 20W-50. Oil pressure seemed a bit low at times so I went with this slightly thicker oil.

Am now thinking about 10W-40 or 10W-30 options as oil pressure even during breakin period has been soild 60psi according to the dash gauge - with new pressure sender. S&J recommend no fully synthetics for first 4500 miles.

Watched the Oil Videos linked - still not really sure what to use.

Any other recent rebuilds care to share what you used?

Planning to switch to NAPA 10W30 full synthetic.

 

[jampants]

Planning to switch to NAPA 10W30 full synthetic.

Thanks - you thinking this one?

https://www.napaonline.com/en/p/NOL75500

 

[Christo]

Yep

 

[Bhart]

Napa oil is produced by Valvoline

 

[tmsnyder]

Planning to switch to NAPA 10W30 full synthetic.

I went with 10w30 full synthetic after rebuilding my engine as a full roller engine. It's probably too thin for our engines though. I think my next oil change will be 10w40. The local Walmart carries Mobil 1 'high mileage' 10w40 for $5 per quart in 5 quart container.

Robot or human?

 

[jampants]

Napa oil is produced by Valvoline

Thanks all. I'm in the UK and can't get Napa here easily - can get Valvoline VR1 but only at 10W-30.

My oil pressure is so much higher than it used to be - I was previously starting at 40 and dropping quickly to low 20s. Now I'm steady 60 all the time. Am getting used to the new readings and trying to decipher from that what may be best.

S&J recommended 10W-40 or 10W-30 fwiw - but not fully synthetic hence the mine field

 

[hylomatt]

I use Valvoline VR1 20w-50 for my GMC. I keep Rotella 15w-40 around for my 99 Jeep Cherokee and use VR1 30w or 10w-30 for my old Volkswagens, depending on the time of year. The ZDDP thing is real and unfortunate. I don't need prematurely worn down camshafts to deal with. Too many other things to maintain on a regular schedule

 

[hylomatt]

I'd love to run a thinner oil because I think The better flowability would get to protecting my engine internals faster at startup and possibly result in better gas mileage while driving.

With that said, does anyone think that 10W-30 is too thin? When I first got my GMC, I think I tried 10W-30, then straight 30w, and finally 20w-50 for a while now. All of them Valvoline VR1. It's kind of a dangerous thing to play around with if you don't have engine rebuild money at the ready.

Any thoughts? Is it pretty much decided based on getting the vehicle up to full operating temperature and the oil pressure you expect at that point?

 

[Tom Katzenberger]

I believe there's enough official and professional information on this thread to make an educated decision. I found it best to let everyone make their own decision. I personally have learned a lot from this thread.

It might be best to sit down with a paper and pen and see what works best for you.

Best of luck and take care,
Tom K.

 

[LarryW]

I'd love to run a thinner oil because I think The better flowability would get to protecting my engine internals faster at startup and possibly result in better gas mileage while driving.

With that said, does anyone think that 10W-30 is too thin? When I first got my GMC, I think I tried 10W-30, then straight 30w, and finally 20w-50 for a while now. All of them Valvoline VR1. It's kind of a dangerous thing to play around with if you don't have engine rebuild money at the ready.

Any thoughts? Is it pretty much decided based on getting the vehicle up to full operating temperature and the oil pressure you expect at that point?

Personally, I would use as thin of an oil as possible that will maintain good oil pressure. (long standing standard is 10lbs per 1000rpm) Thinner oils carry more heat away quicker, supply more oil to bearings in any period of time, and get to bearing surfaces quicker at a cold start. I run 5w30 Quaker State full synthetic and maintain 42-45lbs at road speeds with 25-35lbs at an idle. Oil testing at 3K miles show minimal metals. The 5w30 gives me 5w for start-ups and the 30w for hot running. JMHO

 

[RF_Burns]

I've been using Amsoil Z-rod 10W-30 for years. Dick Paterson says that's the good stuff and that 30 weight is best to help carry away the heat. Along with ZDDP, it is formulated for classic vehicles and has rust inhibitors to prevent corrosion during storage.

https://www.amsoil.ca/p/amsoil-z-rod-10w-30-100-synthetic-motor-oil-zrt/?srsltid=AfmBOophro_REE1vvo3o3lR1qH92ZzAz__3NTWVBUf1vM1jQrHNvbMYZ