A reader asks: I own a Nissan Skyline GTR with the twin turbo RB26 engine. The previous owner used 0W-40 motor oil. I’ve read online that 0W-40 might be too thin. Is 10W-40 a better option? I will not be winter driving it at all, but might occasionally start it up during the nicer winter days to circulate the oil.

0W-40 Or 10W-40 For Nissan Engine?

AMSOIL 0W-40 Signature Series Synthetic OilOur answer: This model was never sold in North America, so it isn’t included in AMSOIL’s application guide. As this is an older car (RB26 models were made from 1989-1994), a search doesn’t seem offer much in the way of official Nissan oil suggestions. Contributors to Skyline forums use everything from 10W-30 to 10W-60.

The previous owner’s use of 0W-40 would be right in the middle of that range. AMSOIL Signature Series Synthetic 0W-40 would be a very good choice. Remember that this product is still a 40-weight oil at operating temps, so there are no grounds to call it “too thin”. It simply has a very wide operating range. Signature Series Synthetic 0W-40 also has a strong resistance to shear-down, metal-to-metal contact and volatility boil-off. It is formulated for turbo-charger service. It meets the latest Nissan GTR motor oil AMSOIL Synthetic 10W-40 Premium Protection Motor Oilspecification. Note that it is also suggested for the 707 horsepower Dodge Hellcat engine. The wear control abilities of this product are not a concern.

Another great candidate for your Skyline would be AMSOIL Synthetic Premium Protection 10W-40 Motor Oil. Premium Protection 10W-40 is an “old school” formula that is loaded with zinc and phosphorus for powerful anti-wear protection. It is also designed to withstand the extreme heat generated by turbo-chargers. Were it our Skyline, we would likely lean toward this product over any other in the AMSOIL motor oil line-up. Not because it is a 10W-40 versus a 0W-40. More so because its high-zinc formula is ideal for older engines.


A reader asks: I own a Mazda RX-8 rotary sports car. At present, some of the engine oil is injected directly into the combustion chamber to lubricate the apex, corner and side seals. This plays havoc with the engine exhaust emissions. What I want to do is to mount a separate tank with AMSOIL 2-stroke oil and pump it into the oil injection system. I think it will do a better job keeping the engine internals clean than engine oil. Which AMSOIL 2-stroke oil would be suitable for this? 

Using 2-Stroke Oil In a Mazda RX- 8 Rotary Engine?

AMSOIL INTERCEPTOR Synthetic 2-Cycle Oil

Our answer: Keeping Mazda RENESIS engines running strong and deposit-free is a well-worn subject for the RX-8 crowd. Injecting or premixing two-stroke oil to reduce rotor seal wear is also a popular topic with performance-oriented RX-8 owners. AMSOIL does not have an official opinion on using 2-stroke oil in Mazda rotary engines. But AMSOIL Technical Services does admit that this a relatively common practice.

Apparently, the best result is attained by using AMSOIL Interceptor Synthetic 2-Stroke Oil mixed at a ratio of 100:1 with the fuel. There are also aftermarket two-stroke injector pump/reservoir kits for the RX-8 engine that feed oil at about 100:1.

Regardless of the delivery method chosen, AMSOIL Interceptor would be the best choice. Interceptor’s high detergent content fights deposit formation. It is also a top-tier product for wear protection in 2-stroke engines. Given its all-star attributes, it would be the best option for this unorthodox function.

AMSOIL has published technical service bulletins stating that their synthetic motor oils are compatible with RX-8 RENESIS rotary engines.

Free Shipping On AMSOIL Synthetic OilAMSOIL is offering free shipping on orders over $100 for Preferred Customers starting on Wednesday, June 14th at 9 am CST and ending on June 20th at 11:59 CST. 

Who Is Eligible For Free Shipping?

AMSOIL Preferred Customers with valid memberships in Canada and the United States. Customers in remote regions may not be eligible (more details below). New customers can activate a membership during the promotion and still take advantage. Brand new Preferred Customers simply need to ask for the free shipping promo code (very important) and place an order over $100 (wholesale price before taxes).

AMSOIL Preferred Customers are able to buy at wholesale prices. Free shipping really sweetens the deal.

How Do You Become A Preferred Customer?

Contact us using the form on this page. We will send over a wholesale price list with more details.

How Do You Take Advantage Of The Free Shipping Offer?

A promo code is required to take advantage of this offer. The promo code can be used for online orders or via the toll-free telephone order line. Established Preferred Customers in the system prior to the promotion announcement will receive an email from AMSOIL revealing the free shipping promo code. For customers that sign up after the announcement email, they can simply ask the operator for the promo code when they call in their order.

Are There Regions Where Free Shipping Is Not Available?

Residents of Alaska or Hawaii are not eligible. Also those in remote locations or situations where a third-party shipper may be used. Please pass along your postal code or zip code and we can determine if free shipping applies to your region.

What Happens To Shipping Rates After June 20th?

After the promotion expires on June 20th at 11:59 (CST), regular shipping rates will apply.

Will AMSOIL Run Free Shipping Promotions In The Future?

We hope so. AMSOIL has been running monthly promotions for Preferred Customers over the past year. The offers change from month to month, but they have generally been shipping or product discounts. What the promotions will entail and when they will occur are a closely guarded secret at AMSOIL.

Questions? Contact us using the form on this page or call us at 1-800-748-5781. 

A reader asks: Why does AMSOIL Dirt Bike 10W-40 have the JASO MA rating and not the JASO MA2 rating like the AMSOIL Metric Motorcycle 10W-40? How important is this?

Our answer: Before we get into the finer details of JASO MA versus JASO MA2, let’s talk about the real-world difference between AMSOIL Dirt Bike 10W-40 (JASO MA) and AMSOIL Metric 10W-40 (JASO MA2).
AMSOIL Synthetic 10W-40 Dirt Bike OilThe starkest difference between these two products is the frictional properties and how this affects clutch performance. These oils are “tuned” and designed for optimum performance. Metric 10W-40 is designed for the street and Dirt Bike 10W-40 is formulated for severe off-road duty.

The Metric 10W-40 will provide smoother clutch operation, whereas the Dirt Bike Oil will be a little “grabbier”. The Dirt Bike Oil has to provide instant clutch engagement while launching out of a motocross starting gate, climbing up a very steep hill or to propel the bike through deep mud or sand. The Metric Oil is designed to provide smoother engagement in street riding situations.

That is not to say that the Metric Oil is any more prone to clutch slippage. We know of professional road racers that use Metric 10W-40 and have reported exceptional clutch longevity and superb performance. Both motorcycle oils are elite and will provide similar anti-wear protection.

What Is the Difference Between JASO MA And JASO MA2?

“JASO” stands for Japanese Automotive Standards Organization. Back in the 1990’s, JASO created motorcycle engine oil standards. One of the main motivations behind these motor oil standards was to signify which engine oils performed capably in wet-clutch operation.

Motor oils for automotive engines contain friction modifiers which can cause severe motorcycle clutch slippage. JASO created standards to offer consumers defined motor oil options for reliable wet-clutch performance.

AMSOIL Metric Synthetic 10W-40 Motorcycle OilJASO MA

The JASO MA standard was developed for 4-stroke motorcycles that use a common sump. In other words, the engine, transmission and clutch all use the same oil. To qualify for the JASO MA specification, a motorcycle oil must resist clutch slippage to JASO standards. The JASO MA spec also defines standards for engine and transmission wear.


As catalytic converters became prevalent on 4-stroke street motorcycles, JASO came up with an oil standard for these applications. The JASO MA2 spec determines whether a motorcycle oil is compatible with catalytic converters. It also has the wet-clutch slippage resistance standard, as well as engine and transmission wear limits.

To Sum Up

Dirt bikes and motocross bikes are not equipped with catalytic converters. Therefore, there is no need to formulate AMSOIL Synthetic Dirt Bike Oil to meet the JASO MA2 spec.

Questions? Contact us using the form on this page or call us at 1-800-748-5781.