Should AMSOIL Z-Rod Motor Oil be used in modern high-performance Chevy engines? You might be surprised by our answer.

AMSOIL Z-ROD™ 10W-30 & 20W-50 Synthetic Motor OilA reader asks: I’ve got a 2013 Camaro SS and my friend has a 2009 Corvette. Both cars have the LS3 engine and have aggressive aftermarket camshafts. The catalytic converters have been removed from the Corvette, while the Camaro has high-flow cats. Both cars see a mix of city, highway and occasional runs at the drag strip. The AMSOIL application guide suggests AMSOIL Signature Series Synthetic 5W-30 for both cars. In light of the fact that the Corvette has no catalytic converters, can AMSOIL Z-Rod 10W-30 be used in it? Would it be a major problem to use Z-Rod in the Camaro as well? The cam manufacturer tells us that more zinc is definitely better for these cams.

Our answer: In most cases you should not use AMSOIL Z-Rod 10W-30 Synthetic Motor Oil in modern engines as it was designed for classic cars and hot rods. Z-Rod has very high zinc and phosphorous content to protect the flat tappet cams of older cars. These high zinc and phosphorous levels can foul the catalytic converters found on modern cars and is generally not recommended. But both of these cars are an exception.

As the Corvette’s catalytic converters have been removed, your friend can safely use AMSOIL Z-Rod 10W-30 and enjoy the extra anti-wear protection with no downside. In the case of your Camaro with high-flow catalytic converters, going to the high-zinc formula of Z-Rod may lead to deterioration of the cats over the very long term, but the trade-off is improved protection of the aftermarket cams.

Z-Rod’s higher levels of zinc and phosphorous will not have an effect on oxygen sensors or other emissions devices. Contrary to popular belief, high zinc does not clog catalytic converters, it simply causes deterioration of the internals. If your oil consumption is minimal, you may never have any issues. Again as both cars have aggressive cams and are raced occasionally, the extra protection offered by Z-Rod over modern passenger car motor oil formulas is a safe and sensible trade-off.

So while the AMSOIL Signature Series Synthetic 5W-30 is the best choice for late model Corvettes and Camaros in stock trim, you can safely go with the classic formula of AMSOIL Z-Rod Synthetic Motor Oil in some modified or raced cars. If your car is unmodified, using a high-zinc motor oil can lead to premature catalytic converter degradation and is not the best choice.

Earlier this year, one of our customers told us about an exceptional car that we immediately wanted to learn more about. Luc F.’s 1987 Lotus Esprit HCI is a classic supercar that is both rare and beautiful. We are thankful that he gave us permission to share it with you.

What separates this machine from your average mass-built sports car is not just its rarity or the hand-crafted leather interior. It’s also not the fact that this Lotus was hand-built in England. What makes a Lotus so special is the engineering that stems from 60 years of extraordinary racing success. We’ve never had the pleasure of driving a Lotus, but by all accounts, it is an exhilarating experience that one will not soon forget.

We were pleased that Luc chose our AMSOIL Z-Rod Synthetic 20W-50 Engine Oil to protect the turbo-charged engine. As this high-compression Lotus engine is equipped with flat tappet camshafts, Z-Rod is a superb motor oil choice.

Luc was generous enough to offer this description of his Lotus along with a brief history of the Esprit model.

“The Esprit is a mid-engine car that designed by Giorgetto Guigiaro from Ital Design for
Lotus cars of the UK. It was presented to the public for the first time in Turin in 1972. The first production Esprit came off the line in 1976.

The initial Esprit came equipped with an atmospheric 2.0L 16V engine designed in-house by
Lotus and was developing 160HP. The engine design was all-aluminum with steel sleeves. It was used in different configurations until 1996. When enlarged to 2.2L with a turbo
and charge cooler, it was producing 300HP in the Esprit S4s.

The car rides on a typical Lotus backbone chassis consisting of a central steel boxed section
which is attached a tubular cradle for the engine at the back and suspension attachments
at the four corners. The body shell is built of fiberglass and consists of two halves glued at
the waste band and bolted to the chassis. This layout was kept until the end of the
production with the last edition of the V8 in 2003.

Two different body styles were used over the years, the Giugiaro design from 1976 to 1987
and the (Peter) Stevens design  from 1988 to 2003.

I bought this particular car from a broker in Pennsylvania after 5 years of checking ads and the internet. It had 21,000 miles on the clock and used to be owned by a collector in New Jersey.
Only around 600 units were produced with the HCPI (High Compression Petrol Injection) engine from
from 1986 to 1987. They featured a Bosch K-Jetronic injection system with a Lambda sensor which was adapted for the turbocharged engine. Other normally aspirated and turbo cars were
equipped with Dellorto carburetors (or Stromberg for the federal version). One of the reasons
this particular model was chosen is the stability that an injected fuel system offers after long
intervals without running it (which can be an issue with carburetor versions).

This car is one out of just 12 cars in the black and gold color scheme issued for the USA market. Total turbo production  numbers for the G model were around 2200 units which makes it a pretty uncommon car. Prices are surprisingly low and part of the reason is the perception by the public of the
fiberglass structure and parts availability. On that subject, it is a misconception to believe
that parts are hard or extraordinarily expensive to get. There is a great market out there for
these cars and since the engines are sleeved, available kits allow you to overhaul your
engine without even coming close to what a Ferrari or Porsche engine rebuilt would cost
you. There is also great support from Forums (The Lotus Forum from UK comes to mind)
where no questions remain unanswered. This is a real bonus when you are new to the brand.
Maintenance is a pain (like any mid-engine car), but it is part of the fun of buying an exotic
car. Like any special car, if you don’t take care of maintenance yourself, costs can get
astronomical. That been said, with a little patience, the right tools and good advice, it has been a
very reliable car up to now.

Driving the Esprit is really special, it feels like what you would expect from a Lotus. Very
direct and connected to the road, sometimes a little too connected on rough back roads.
This car feels at home on nice sweeping roads or highway at any speed. You will get up to speed in a very linear way with no sudden push from the turbo and you will get there fast if
you keep it on the boost. Lag, like any turbo of that era is an issue, you just need to learn to
deal with it.”

Thanks very much to Luc F. for sharing his photos and offering a description of this very special car.

Chevy Big Block 427 L72 Spec Engine

Should this Chevy Big Block 427 get 10W-30 or 20W-50 motor oil? (photo credit:

A reader asks: My street rod has a 1967-vintage Chevy big block 427 (L72 spec) with solid lifter cams. This car runs only in the summer and has an estimated 450 horsepower. I would like to run AMSOIL Z-Rod in this engine, but I’m really torn between 10W-30 and 20W-50. There’s so much debate on the internet about which grade to use. Can you offer any thoughts?

Answer: This is a very contentious and well-worn subject, but there is actually no wrong answer. There is no downside to going with 10W-30 or 20W-50 motor oil in your engine. It really comes down to personal preference. As your engine does put out significant horsepower, we would lean toward using 20W-50.

If your engine sees very light duty or is built exceptionally tight, 10W-30 would be fine. But again, if you twisted our arm, we would give 20W-50 the nod for the thicker viscosity.

Regardless of which viscosity is chosen, AMSOIL Z-Rod is formulated expressly for older engines. Packed with 1440 ppm of zinc and 1320 ppm of phosphorous (serious anti-wear additives), Z-Rod is a superior choice for classic engines. These anti-wear agents make Z-ROD Oils especially suitable for engines with flat tappet camshafts.

Motor oils specified for modern cars and trucks are anemic by comparison with zinc and phosphorus levels averaging in the 800 ppm range. Today’s cars and trucks have emissions equipment that do not react well to high zinc and phosphorus levels. Therefore the latest motor oil specifications take a different approach to wear control.

But as emissions equipment are a non-issue for classic engines, this motor oil has no formulation constraints. The 100% synthetic base oil of Z-Rod provides tremendous shear strength and maintains consistent viscosity, regardless of high engine temperatures or hard operation.

There is absolutely no downside to going with a synthetic oil like Z-Rod in vintage engines. You will not see increased oil consumption or leaks. Z-Rod Oils also contain special additives that condition seals to extend their life.

As vintage cars tend to retire for the winter, AMSOIL also gave Z-Rod a healthy dose of anti-rust and corrosion agents. So you can rest well knowing your baby is well-protected whether she’s running or not.

So regardless of whether you opt for 10W-30 or 20W-50, you will have done your engine a favor by choosing the AMSOIL Z-Rod Motor Oil series.

Last week, we profiled our customer Tim’s dazzling 1968 Oldsmobile Cutlass Supreme Two-Door Coupe. This week, let’s take a look at his other classic car that’s arguably even more engaging. This car is Tim’s 1948 Chevrolet Stylemaster 4-door Sport Sedan that has been transformed into a North Carolina Sheriff’s Car. Like the Cutlass, this vintage gem is no garage queen.

The Sheriff Car was originally built in Georgia and eventually ended up at The Hot Rod Shop of Woodland Hills, California. The owner of The Hot Rod Shop exhibited this car at LA-area car shows and it was often displayed alongside of Jay Leno’s classic cars. Tim purchased the car from the California shop in 2014. Tim tells us that he’s owned a few classic cars in his day, but none elicit the response that this car can. When Tim and his wife Kathy take a drive in the Sheriff car, heads turn, truckers honk their horns and people rush to take pictures. Not surprisingly, a crowd immediately gathers wherever they park this car.

Tim uses AMSOIL Z-Rod 10W-30 Synthetic Motor Oil for classic cars in the Sheriff Car’s engine.

Highlights Of Tim’s 1948 Chevrolet Stylemaster Sport Sedan North Carolina Sheriff Car

Body & Frame:

  • All Steel Factory Straight Sedan Body Mounted On A 1985 Chevy S-10 Pickup

Engine & Transmission:

  • 1969 350 Small Block Chevy – Higher Horsepower 4-bolt Main
  • 1969 Turbo 350 Automatic Transmission
  • 10 Bolt Open Differential Rear Axle w/ approx: 3:42 gears
  • Aluminum Radiator
  • Summit 4V 600 CFM Carburetor
  • Edelbrock Performer Intake
  • HEI Distributor & 1-Wire Alternator
  • Custom Aluminum Air Cleaner Box
  • Tall Chrome Valve Covers & Breather
  • RV Cam (for a mild rumble and lower RPM range)
  • Mechanical Fuel pump
  • Chassis Mount Transmission Cooler
  • Higher Than Stock Torque Converter
  • Chrome Oil Pan
  • Custom 22 Gallon Gas Tank
  • Magna Flow Exhaust


  • Brand New Interior- With new headliner, seats, door panels, kick panels, package tray,
    carpet, seat belts, visors, and classic 3-spoke hot rod steering wheel
  • 1948 Police Radio

Steering & Brakes:

  • Tilt Steering Column
  • Power Steering (steering is one finger EASY)
  • Power Front Disc Brakes
  • Rear Drum Brakes


  • Independent Front Suspension


  • Red “Cherry Light” On Roof,
  • Chrome “Safety Star” Brake Light
  • Functioning Siren (with authentic sound!)
  • Chicago Vintage Unity Chrome Spotlight
  • Cowl Vent Works With Under-Dash Actuated Lever
  • Chrome Front Push Guard and Rear Push Guard
  • Rear Package Tray Brake Lights
  • 1956 Chevy Bel Air Hood Bird
  • Electric Windshield Wipers

Thanks very much to Tim for sharing his beautiful cars with us!

Every one in a while, a customer sends along pictures of their vehicle that stops us in our tracks. Seeing pictures of Tim’s two show-stopping collector cars was definitely one of those times. Tim has a 1968 Oldsmobile Cutlass Supreme Two-Door Coupe and a 1948 Chevrolet Stylemaster 4-door Sport Sedan that is fashioned as a North Carolina Sheriff Car. For now, we’ll profile the Cutlass and showcase the Sheriff car in the coming days.

Tim purchased this Cutlass five years ago and is just the third owner. The previous owner had spent a decade restoring the car and as you’ll see below, the results are quite spectacular. Not only does this Cutlass turn heads, with an estimated 400 horsepower, it also gets up and goes. For Tim and his wife, cruising in their Cutlass is a favorite pastime. It is smooth, comfortable and has an unbelievable exhaust note. Tim uses AMSOIL Z-Rod 10W-30 Synthetic Motor Oil in the 350 Rocket engine.

Highlights For Tim’s 1968 Olds Cutlass Supreme Coupe

  • 350 Rocket Engine, Bored 30-over – 355cu. in.
  • 650 Edelbrock 4BBL Carb
  • 468 Lift High Performance Cam
  • Flow Tech Headers
  • Turbo 350 Transmission – 3000 Stall Converter
  • 12 Bolt GM Positraction Differential
  • 3.08 Rear End
  • Custom Aluminum Racing Driveshaft
  • B&M Floor Shifter
  • American Racing Torque Thrust II Mag Wheels
  • HEI Distributor
  • Northern Aluminum Radiator With Built-in Transmission Cooler
  • Mechanical Fuel Pump
  • Interior Redone Except For Door Panels (original)

A question from a reader: “Do you offer a motor oil for my 1976 Triumph TR-6?”

AMSOIL Z-ROD™ 10W-30 & 20W-50 Synthetic Motor Oil

AMSOIL Z-Rod Motor oils are the ideal choice for classic car engines.

Answer: For most classic cars such as your TR-6, the AMSOIL Z-ROD motor oil series is the logical choice.

First let’s discuss why a motor oil meeting the very latest industry specifications might not be the best choice for your car. Engine oils for today’s cars have to meet formulation guidelines in order to be compatible with modern emissions components. Today’s cars have numerous sensors throughout the engine and exhaust system that monitor operating conditions to keep emissions to a minimum. Anti-wear ingredients such as zinc and phosphorous can cause fits for these electronic sensors, so modern engine oil industry specifications place strict limitations on these additive levels. Don’t get us wrong, the latest oils do a spectacular job of fighting wear, but it requires that oil makers use high-end base oils and a very sophisticated approach to motor oil composition.

As theses constraints are not an issue with your Triumph, using an oil like Z-ROD that is designed for classic vehicles (and therefore is loaded with traditional anti-wear additives) is definitely the way to go.  A quick search shows that many TR-6 owners use 20W-50 and if that is indeed suitable for your car, then Z-ROD 20W-50 would be an outstanding candidate.

Also consider that vintage cars are generally not driven often and tend to spend much of the year in storage. Z-ROD contains a potent anti-rust/corrosion package for long-term storage, which would be an added bonus for your engine’s internals.

AMSOIL Z-ROD brings modern synthetic performance and anti-wear technology to the great cars of yesteryear and is an unbeatable motor oil selection in this case.