Engine oil choices for MG V8 engines

This is a frequent query from MGV8 enthusiasts, particularly new MGV8 enthusiasts, so what are the issues and views of fellow V8 members.

See the V8BB thread on engine oils. More

See our note on MGV8 engine oils. More

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Which brand and which specification do you choose when changing the engine oil on an MGBGTV8 or an RV8?
This is a frequent query from MGV8 enthusiasts, particularly new MGV8 enthusiasts, so what are the issues and views of fellow V8 members.

RV8 owner Malcolm Roots launched a V8BB thread saying "the car came with a comprehensive history file which shows that it has been serviced and maintained regardless of cost. However on going through the history filethat came with the car I found a service record in 1999 that stated noisy engine on start up and which suggested the incorrect grade of oil had been used. I wonder if this contributed to the excessive wear on the bearings or if anyone has experienced this kind of problem at what is a relatively low mileage.

The car was serviced by the same MG Rover dealer in 1996, 1997 and 1998 but the grade of engine oil used was not documented. In 1999 a different MG Rover dealer serviced the car and wrote the following comment on the service record "Noisy engine on start suggests the incorrect grade of oil had been used. Recommend an engine flush using Wynns or STP flush additive and oil and filter change using fully synthetic engine oil". Malcolm wondered whether it a mistake if fully synthetic oil was used? The car changed hands later that year and has always been serviced by MG Rover dealers or MG specialists. The grade of engine oil used has never been documented on the service records but the oils recommended and used this time and fully documented are Valvoline 20w50 for the engine, Castrol SMX for the gearbox and Hypoid EP80W90 for the rear axle.

Victor Smith, V8 Webmaster, posted a note on V8 engine oils on the V8BB saying "I have uploaded a webpage with lubrication information for the MGBGTV8 and RV8" with links to several information notes:

> Lubrication information for an RV8
This note reproduces two pages from the section Capacities, Fluids & Lubricants, pages 2 & 3 in the RV8 Repair Manual AKM7153ENG which sets out the recommended engine lubrication specifications. More

> Castrol engine oils for pre-1980 classic car engines and for the MG RV8
This note provides information from the Castrol website and mentions that whilst Castrol indicates changing the engine oil on an RV8 at 12,000 mile intervals or 12 months (whichever is the earlier), the recommended advice from the V8 Register is that an engine oil change on the Rover V8 engines fitted to the MGBGTV8, MGV8 conversions and the RV8 every 3,000 miles or 12 months maximum is a better service routine. This is because the lubrication system in a Rover V8 engine is a “high volume - low pressure” system and the oil passageways leading to the rocker shafts are prone to sludging up which can lead to a reduced flow of oil to those areas. More

> MGBGTV8 lubrication chart
This note has a copy of the recommended lubricants chart in the MGBGTV8 Driver's Handbook AKD8423. More

Mike Howlett, whith an MGBGTV8 conversion, added "I support the notion that oil should be changed more regularly than in many modern cars, and I change the oil in my my 3.9 litre engine every 3,000 miles. One way to see the overall health of the V8 is to remove a rocker cover. If there is black sludge inside the cover and on the rocker gear, the engine is not generally in good order. When my engine was rebuilt by Real Steel, the V8 engine specialists in London, they recommended using Valvoline VR1 20-50, and I have stuck with that oil, buying 4 gallons at a time off ebay.

As for a V8 engine being noisy on start up, my engine rattles for a few seconds if it hasn't been used fror a couple of days. This is just the hydraulic tappets having drained and needing the oil to refill them before they quieten down as the oil pressure rises."
Members' engine oil choices for an MG V8 engine

Valvoline VR1 20-50
The information on the Valvoline website provides information on their VR1 engine oil. Website & Product information sheet

What is motor oil with zinc?
The anti-wear additive simply referred to as zinc by most car enthusiasts is actually short for Zinc DialkylDithiophosphates or ZDDP. Its primary role is to prevent metal-to-metal contact between engine parts by forming a protective film. Despite being referred to as zinc, this additive actually contains zinc and phosphorus, with phosphorus performing the anti-wear function in the motor oil with zinc. More

Why is it important to have the zinc/phosphorus levels in motor oil changed?
With ever increasing limits on emissions, automobile manufacturers have tightened emission control systems on newer vehicles. This is one of several factors considered when the American Petroleum Institute (API) sets standards for motor oil with zinc. The current API standard is SM which replaced the previous SL classification. Because phosphorus can poison a vehicle's emission system, the level of zinc is lower for current motor oil.


What is the controversy surrounding the amount of zinc in motor oil?
Many hands-on car enthusiasts and engine experts believe the lower levels of zinc in SM motor oil is causing excessive wear in older style push-rod and flat-tappet engines. This is despite the fact that all new motor oil classifications are intended to be backward compatible. This has resulted in the widely accepted belief that modern motor oil is not adequate to protect older engines.


What solutions does Valvoline offer to the zinc issue?
Valvoline offers two solutions to the zinc issue:
> Valvoline VR1 Racing Oil: Contains 75% higher zinc than SM motor oil with a balanced additive package designed to work in both racing and street-legal applications. This product will protect older style push-rod and flat tappet engines. Valvoline provides this product in both multi and mono viscosity grades: 20w50, straight 50, 10w30, straight 30, straight 40, and straight 60.
> Longer-Lasting Zinc/Phosphorus: Valvoline uses an advanced zinc/phosphorus additive that keeps higher levels of phosphorus in the motor oil where it protects the engine instead of poisoning the catalytic converter. Valvoline is the only brand offering this unique additive across its entire line of passenger car motor oils including SynPower -- the only synthetic oil that offers this additive.


Is VR1 a conventional oil, a synthetic or a blend?
Valvoline VR1 racing oil is a conventional, non-synthetic racing oil.

Castrol Magnatec 10W-40 A3/B4
The Castrol website says their Magnatec engine oil provides "instant protection from the moment you turn the key. No engine likes a cold start - unless it's protected by Castrol Magnatec. With 75% of engine wear as your engine warms up, it's essential your car is protected from the start. Castrol Magnatec's intelligent molecules cling and bond to critical engine parts, providing protection before, during and after your journey."
More & More

An old favourite with many MGV8 enthusiasts, the Castrol GTX oil range provides a balanced performance under all types of conditions. It is specially engineered to prevent the harmful build up of engine sludge, reducing oil deposits and providing everyday protection for your engine. In addition, GTX 15W-40 A3/B3 is a product which was designed especially for engines with a mileage of over 70,000 miles (100,000 km). Next time your car needs an oil change or a service, specify Castrol GTX to help maintain your engine's performance and avoid the build up of harmful deposits. More
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