MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB Technical - Castrol 20/50 oil

Hello, I have been using Castrol 20/50 oil in my 1967 MGB. I have been offered some gallon cans of Halfords Classic oil on the cheap, is this oil on a par with Castrol as I only do around 1500 miles a year.
RR BLACKSHAW

The oils listed as "classic" usually have levels of zinc and phosphorous that were used when our cars were new. It should work just fine with the B's flat tappet cam. RAY
rjm RAY

And the other good thing, is if you have been offered many cans, you could afford to change the oil more often. With little milage should last you a number of years? Mike
J.M. Doust

Halfords Classic (made by Comma) cans are unsealed, i.e. anyone could add anything to them at any time, so I only bought one once. I don't know why this should be, all the other containers have a seal you must break, and those metal cans always used to come with a pressed-in seal you had to pierce and lever out when those cans were the norm. The ACEA/API classification on the containers are important, as is the manufacturers statements on formulation, which varies from market to market. The best oils for zinc and phosphorus are those stating suitability for both petrol and diesel, e.g. Halfords Enhanced Diesel which states (last year anyway) API CF-4 CF SJ the C classifications being for diesel and the S for petrol, as diesel engines need more protection than petrol. After SJ the levels of zinc and phosphorus started dropping to protect catalysers and the environment. You need to be careful with so-called classic oils, if to the *original* formulations then they could contain significantly less zinc, phosphorus and detergents than later formulations such as SF to SJ (e,g, Castrol XL 20W/50 is SE), and if they are not to the original formulations then you won't know what they contain, Castrol GTX for example has apparently reduced it's zinc and phosphorus by half over the years. More here http://www.mgb-stuff.org.uk/enginetext.htm#oils

There is also the question of storage, I have read it should be kept a maximum of five years and even then frost-free.
PaulH Solihull

Paul makes an excellent point. The oils, sold in the U.S., have progressively lowered their ZDDP levels, over the past 10 years, to meet government requirements that mandate emission equipment last at least 100,000 miles. The ZDDP has a tendency to clog catalytic converters and void their warranty. I use a Castrol oil that is designed for off road use, so it gets by Federal regulations, requiring lower ZDDP levels. Castrol markets the oil under the name of 4T and it is available in several weights. Five to six years shelf life is the accepted limit for oil nowadays. RAY
rjm RAY

And I'll add that, as best I know here in the States, the days of buying oil for diesel engines to get the extra ZDDP are over. They dropped the ZDDP content in those oils 2 or 3 years ago. You can identify the new diesel motor oil by its designation if you know it, or by its claim on the label to be clean burning/lower emissions, or some such claim. I usually run a Valvoline racing oil in my MGs, which is probably similar to what RAY uses.

Charley
C R Huff

Here is an extensive article on engine oil for classic MGs written by Martin Williamson who is an oil engineer. He covers various topics if you click on the links at the left of the web page.
http://www.kewengineering.co.uk/Auto_oils/index.htm
Mike Howlett

This thread was discussed between 27/01/2011 and 29/01/2011

MG MGB Technical index

This thread is from the archives. Join the live MG MGB Technical BBS now