Morris Minor Owners Club

Chris, I'm sure your engine is just sublime

Chris, I'm sure your engine is just sublime

Dunno if it's sublime, but it's worked perfectly well for the last 7 years. Like most well-used Minor engines it will drop a bit of oil after a thrashing on the Motorway.

Kevin's trying to wind me up about a moderate loss of oil that I had at a messageboard rally (due to a split rocker cover gasket) Really it's amazing that his ancient brain can still remember something that happened more than two years ago! At least I've never had to replace my Minor's engine like a certain Mr. Daly....

Basically an oil with a SAE hot rating of 50 is going to be 25% more effective than one with a rating of 40. This effect is down to the ratio of long-chain polymers in modern blended oils. As a Minor's engine is likely to be well worn (and not built to close tolerances in the first place) it's sensible to use an oil which has the best viscosity when hot. Hence why 20/50 is quoted by just about everyone for the Minor's engine. Theoretically by using an oil with a SAE40 rating you are risking increased wear when the engine is running at higher rpm. In reality I guess it makes little difference in Garelochead!

Hi Chris, too true..up here in Gairloch. No speed track (super slab)up here, lucky if the car gets to above 40mph most times....but as I said, I'll stick to my previous experience on this issue...

Oil with a Winter SAE rating of 20 is OK down to -10C, so the use of 10W is probably overkill, even where you are. Chances are you're doing your engine no favours whenever you start it unless the temperature is well below freezing.

Here's an interesting on-line article about oil technology.
http://www.volvoclub.org.uk/engine_oil_history.shtml

As I said...used it for a number of years now with no problems. Only cars I dont use it in...Mercs and the 8 seater limos. I use it in most of the cars that are out for funeral and wedding hire too....never had a problem. In fact...one of the taxis has it.....with a 145,000 on the clock and still going...lol oops, getting away now from the issue here...they are not Minors....

There is a mention of 30SAE oil for the engine in the text of the lubrication section of the workshop manual, but I think it is a hangover from the original version of the manual, when multigrades weren't available.

All the tables in the manual show 20W/50 as being the recommended oil for normal temperatures.

(Also use this for the gearbox).

Axolotl wrote:There is a mention of 30SAE oil for the engine in the text of the lubrication section of the workshop manual, but I think it is a hangover from the original version of the manual, when multigrades weren't available.

All the tables in the manual show 20W/50 as being the recommended oil for normal temperatures.

(Also use this for the gearbox).

As I have already said....I'll trust in my own experience....and grade oil as conditions dictate.