Even back when the cars were new, many Canadians didn't drive their Jaguars in the winter. The heaters up until the Series III XJ6 were really inadequate and also many didn't want to expose their cars to the salt and gravel that gets spread on the roads in the winter. Thus the concept of a "winter beater" - i.e a somewhat disposable car that is driven in in the harsh winter conditions, while the "good" car stays in the (heated) garage all winter.

Summers, especially in southern Ontario and Quebec can be hot and muggy and places in the BC interior are a true desert. Last year some of them got to nearly 50°C. So I wouldn't choose a damper oil based on the idea of cold ambient temperatures for a Canadian Jaguar.

 

Absolutely. Much of my family lives in Canada. My Dad was Canadian. He came to SA after the war because the cold bothered him & skating to school on the river. And his 2 brothers went home to Canada, Today our family shuttles back & forth. My Sister is off to see my nephew & family shortly.

See responses to your PM.

 

Glyn



“……………………………I would be reluctant to put a 20W-50 in the dampers (which on the face of things would seem a good idea at operating temperature that low). I'm not sure milled polymer in that volume is a good idea. I would stick to monogrades. Ideally a 20W synthetic. People must do as they wish. Reality is they are going to anyway. I know many favour a 10W ATF. It's really too thin……….”.

Glyn

I would agree with those comments, I should have made my point a little different viz……….

Since at least the mid 30’s S.U have specified S.A.E 20 oil (but no thicker than S.A.E 30) for their dampers, their thinking being that monograde engine oil would be available in all the engine makers overseas territories. At that time and into the 60’s the winter grade S.A.E 20 was listed for almost every UK car.

You will find that the valve itself on the damper is designed to work with S.A.E 20 oil under ALL operating conditions in most zones, not just acceleration (Canada winter excepted). It is one reason why S.A.E 10 is usually found to be too thin in normal times and anything over S.A.E 30 raises particular problems not discussed in these forums.

Rolls-Royce conducted extensive cold tests on S.U dampers. Even during development of their Silver Cloud II / Bentley S2 V8’s they tried EP140 in S.U dampers. For their Canadian market S.A.E 10 was standard for dampers along with S.A.E 10 for the starter drive lubrication and the fitting of cylinder block heaters.

For any doubt, at least at the time of production of our cars, all S.U service sheets specified S.A.E 20 oil in the carburetter dampers. I have originals of these S.U service sheets and extensive copies of R-R carburetter testing.

 

Thanks for the clarification Norman ~ no arguments intended & fully understood. You are a man with the experience. We agree!

I had copies of the Service Sheets when I was in Dallas. Now they are in a box somewhere that I don't feel like scratching for. Wish I had scanned them & held electronic copies.

When you are dealing with the lubrication of Mining one day, Steel the next, Pulp & Paper the next, Cement the next, Sugar the next, Marine the next, Food & Bev the next & Power Generation the next etc, etc, or all at the same time. SU damper oil is not high on the priority list.

 

Norman's discussion and explanation sounds very good to me. Lower temperature, less fuel vaporised, the engine needs more enrichment and that means a more viscous oil in the damper to slow down the piston. And that's all done automatically by a monograde oil. SU carbs were around so long because they're a very clever design.

 

Absolutely ~ a Monograde is the answer or a very high VI synthetic base oil that covers a multigrade range without the addition of VI Improver. e.g. a 20W-30. Norman & I are agreeing with one another violently. LOL!