What oil are you using in an older flat tappet motor?

[Nickelcharlie]

I have an 86 GMC with the original flat tappet motor. Should I be using an oil such as Rotella made for diesel motors or can I use a synthetic oil? I have also read once a flat tappet motor has been broken in correctly a synthetic oil can be used! So I would like to hear what you have been using successfully in your older motor for a long period of time?
My owners manual lists multi grade oils so I am thinking it is alright to be using any brand quality oil. Thanks for your input in advance!

[Bandit130]

I had a cam/heads rebuild last April. Did some research and found recommendations to use oil that has zinc and phosphorus. Started using Valvoline VR1. Haven't noticed a difference but hopefully it is good for flat tappet cams. Do some research and decide the oil you would like to use.

[Getter-Done]

I have started using Amsoil in my stuff.

I really like it.

Its a little higher than normal oil is currently.

So the liitle bit extra money is worth it too me for Better Oil.

Link: https://www.amsoil.com/lookup/auto-a...lume=us-volume

[Hammered 77]

I use "Brad Penns" oil, recommended by machine shop.

Rick

[MJN]

I run AMSOIL Z-Rod 10w30 in my '74. I also used AMSOIL Break-in oil when I rebuilt the engine, no issues, no leaks and no consumption. Everything AMSOIL makes is full synthetic.
https://www.amsoil.com/p/z-rod-10w-3...motor-oil-zrt/

Another alternative to Z-Rod that also has higher levels of zinc would be AMSOIL Premium Protection 10w40.
https://www.amsoil.com/p/premium-pro...motor-oil-amo/

Also- here is a good write-up about the differences between racing oil and regular motor oil.
https://blog.amsoil.com/racing-oil-v...he-difference/

AMSOIL offers a Preferred Customer program that saves you 25% off MSRP and you get free shipping with orders over $100 along with other benefits too.
https://www.amsoil.com/offers/pc/
Another thing about pricing- Amsoil adjusted their prices three times in 2021 whereas their competitors did six or more times and usually by 10% or more.
This is a great website to learn more about whats happening within the lubricant industry;
https://jobbersworld.com/category/lubricant-news/

[SCOTI]

I use 'Driven' racing oil w/the ZDDP additive.

[sick472]

I've been using the Rotella 15w-40 in my older V8 vehicles ('67 to '85) for several years now. 13k miles on one, 2k on another, and 20K on a well used 350 which has recently been rebuilt with 2k on it currently...so, not a lot of miles on any of them and no oil expertise on my part. It is said to have more zinc than most AND I like the way it smells, lol.

[ACS]

Originally Posted by sick472

I've been using the Rotella 15w-40 in my older V8 vehicles ('67 to '85) for several years now. 13k miles on one, 2k on another, and 20K on a well used 350 which has recently been rebuilt with 2k on it currently...so, not a lot of miles on any of them and no oil expertise on my part. It is said to have more zinc than most AND I like the way it smells, lol.

Same. I buy it by the 5 gallon bucket and change it regularly with a quality filter.

[fordguy40]

Mobil 1 w/ZDDP. Goodwrench "base" 350.

[72c20customcamper]

GTX classic high zinc it’s on the shelf at Walmart and my autozone

[truckin 79]

I use 10w-30 Walmart high mileage synthetic oil with a mobile-1 filter. I feel like the synthetic helps with less oil leaks and my engine has at least 164,000. I just use it as my junk yard hauler but have put a lot of miles to WY and Denver.

[MikeB]

Originally Posted by Bandit130

Did some research and found recommendations to use oil that has zinc and phosphorus. Started using Valvoline VR1. Haven't noticed a difference but hopefully it is good for flat tappet cams.

It's more than adequate, especially after the engine is broken in. I suspect stock engines with low pressure valve springs rarely experience wiped lobes with any kind of oil that's changed regularly. Breaking-in a new cam & lifters is a different story. I used Driven BR-30 for my last flat tappet engine break-in, then changed to VR1 after a few hundred miles.

Info on Driven BR-30:
The same high Zinc and Phosphorus formula as our original break-in oil, now in an SAE 5W-30 viscosity for modern OEM rebuilds and hydraulic lifter engines. Provides excellent ring sealing. Does not require additional ZDDP additives. Good for full power pulls on the dyno, one night of racing or up to 400 miles on the street. Viscosity typical of 5W-30.

[hatzie]

Any of the diesel oils with higher Zinc and Phosphorous content like Rotella T5 & T6, Mobile 1 TurboDiesel Truck, Chevron Delo, Mobil Delvac, and several others.
I run the higher zinc/phosphorus witches brews in my Aircooled engines.

Here's a ZDDP oil list.
https://www.autorestomod.com/oil-zddp-list.html
I would look up some recent virgin oil analysis sheets on BobIsTheOilGuy if you're really worried. Over 1200ppm are good numbers but over 1100 is pretty good. A lot of gasoline engine oils average 600-800ppm.

[Sabaka454]

Just buy a case of this and drop one in at each oil change.

https://www.stp.com/products/oil-add.../oil-treatment

[MikeB]

Originally Posted by Sabaka454

Just buy a case of this and drop one in at each oil change.

https://www.stp.com/products/oil-add.../oil-treatment

It's better to buy oil with adequate levels of ZDDP so you don't overdo it with an additive, which can create other problems.

From Driven Oil: If you have too much ZDDP, you start to see corrosive wear and cause another problem. Adding an excess causes the oil to become acidic, and before you know, you’re wearing cams, bearings and bushings because of too much ZDDP.

The problem is you're flying blind if you don't know how much ZDDP is in the oil's additive package. I even recall an article by the makers of a ZDDP additive that describes how to calculate the proper amount of their product to add to a motor oil. That amount depends on how much ZDDP the oil already has.

By the way, STP is a "viscosity index modifier", in other words it thickens oil, which your engine may not need or even like. However, if you have an old engine with blow-by, low oil pressure, etc., then go for it! But I'd probably just start using 20W50 oil instead.

[Loco83]

Been running Pennzoil 10w30 since forever and Fram/STP filters,no need for boutique high price oils, just change your oil regularly. 5K for me.

[TALLone71]

I use vr1, in all of my flat tappet engines, and on a new cam, a bottle of comp high zinc oil additive for the first 500 miles..and have seen good results with rotella too, at the shop where I work

[Axle]

Originally Posted by 72c20customcamper

GTX classic high zinc it’s on the shelf at Walmart and my autozone

Got my interest, until I looked it up and they do not offer it in a 10w30. I drive my truck in the winter, 20w50 and 15w40 isn't an option. Secondary rant; even here in the cold north seems nobody carries anything but 15w40 diesel oil.

[hatzie]

Originally Posted by Axle

Got my interest, until I looked it up and they do not offer it in a 10w30. I drive my truck in the winter, 20w50 and 15w40 isn't an option. Secondary rant; even here in the cold north seems nobody carries anything but 15w40 diesel oil.

Shell Rotella T6 is 5W40 here in the states.
Canadian Tire has 0W40 Shell Rotella T6 on their web page. I'd love to be able to buy that for my sled. Not sure if they stock it in the stores but you should be able to find it North of the border.
https://www.canadiantire.ca/en/pdp/s...-0287935p.html

[greenmtnboy]

Mobil1 15w50 has 1300ppm Zinc and is available at Wally World.

[Corts60]

Read carefully on the newer diesel oils. Delo 400 now has its LE version which stands for low emissions and they’ve removed a lot of the zinc.

[68post]

I use HyperLube Zinc replacement additive.
It is a synthetic polymer ester that provides better protection than zddp, doesn't change the base oil's chemistry (won't harm catalytic converters either), and will even provide enough wear protection that you can drop to a lower weight grade.

I've stocked-up several 12oz bottles @ $9.62 ea and you only need 1 oz per oil qt.

[Ziegelsteinfaust]

1/2 a bottle of break in additive is a good option when proper oils are hard to come by.

[old Rusty C10]

i tend to use the semi synthetic high mileage Castrol oil

[chris989]

Lucas hot rod 10/30

https://lucasoil.com/products/hot-ro...w-30-motor-oil