Jaguar (pre-Ford) oil specs

Messages
50
Location
eastern, Pa
About 18yrs ago, I used to work for a Jaguar dealership. I remember the only oil used in those engines(inline 6cyl & V12) was 20W50, all year 'round, regardless of temperature. If I recall correctly, this was a specification that came directly from the manufacturer. Doesn't this seem a bit odd by todays standards? What would compell Jaguar to recommend such a heavy oil across the board?
 
Messages
13,132
Location
By Detroit
That does seem odd. Some of the Valvoline fleet oils are only available in 15w40 which makes me wonder how one uses even that weight in winter. I think there are additives that can improve cold starting--namely synthetic oil, perhaps 1/2 to 1 quart mixed in. The higher W number certainly implies a more robust base oil and less viscosity index improver polymer additives, which is very good for hard running, but I am a little leary of going higher than 10w where I am (ususally not much below zero F weather).
 

TC

Messages
1,644
Location
California
For what it's worth, my '94 BMW called for 20w/50 for temps above 32F, and I believe my '88 Jag XJS was the same. That's not too far off from what your dealer did. Not long after buying it used and changing the oil, I drove the big, 4-door XJS from L.A. to Las Vegas. Near Stateline (out in the middle of the desert), I turned onto a deserted side road for several miles to see what she could do. After hitting 132 mph I could swear I heard a new, very subtle, and permanent rod knock I didn't hear before. Hey, you only live once!
 
Messages
450
Location
Louisville, KY
quote:
Originally posted by TC: . After hitting 132 mph I could swear I heard a new, very subtle, and permanent rod knock I didn't hear before.
[Frown] What oil did you put into it? In my nissaninfinitiownersclub we often got deep in the triple digits just for fun (conditons permitting), a few westerners claim to have spent an entire hour at speeds very similiar to the one you mentioned. Anyone here can relate possible cause of a rod knock due to this? 132 mph is still a somewhat moderate speed with a powerful engine and europeans used to maintain those speeds for some time (until traffic condtions and enforcement became too bad in last 15 years) I wonder if some kind of mechanical of lubrication isue was at fault. Fred [I dont know]
 
Messages
2,480
It's just perceived "thick" because you guys are used to pouring water-thin 5-30's into the engine. I admit, the 5 may be a good thing, but the 30? Odd? Not entirely. I just did another interval with 10-60 in my car yesterday...and we're headed into winter. However, I do think that back then (and even now?) the only non-synth. 50 weights are 20-50...it's only with synth's that you can get 5-50, 10-50, and 15-50.
 
Messages
8,711
Location
Nothern USA
Two points on the 20W-50 1 Forget jolly old England and the Yule log. That goes back hundreds of years. The present English climate is much milder than much of the USA. 20W-x may be OK for England. 2 Jaguars were never know for durability. Maybe they would hold up better if they used an oil that made it out to be bearings instead of back to the crankcase through the bypass.
 

TC

Messages
1,644
Location
California
Hmmm...Definitely a case of brain fade on my part, but I only owned the car for about 6 months. It was an '88 XJ6. I had Amoco 20w-50 and either a Purolator or Fram filter in it. (Ouch! -- I wasn't aware then that orange things could be toxic.) I seriously doubt if it was an oil or filter problem since there was certainly nothing wrong with the oil, and even a lowly Fram when new could flow sufficient oil to keep the engine from imploding, assuming at least 6 gpm (3 media + 3 bypass). I don't know what happened, but am not quick to blame either the oil or the filter. That was a wonderful car, but too bad they were so quirky. $800 for rear shock absorbers? Ouch! [ November 20, 2003, 06:14 PM: Message edited by: TC ]
 
Messages
144
Location
98281
I apprenticed at Jaguar's many years ago. If I remember the crank of their venerable six cylinder is long and it flexes. The main and big end clearances average over one thou more than a modern v8. Subsequently there was allot of leakage from the shells as the car was driven. Very very high flow oil pump to keep up with the leakage from the bearings. And God help you when the rings started to go ( lost heat temper from overheating ). Oil consumption would go through the roof will all the extra oil splashing about inside. 20w-50 was the oil recommended and used by most users back then and still today in my town.
 
Messages
666
Location
Triad, NC
Absolutely, my dad blew three V12 jag engines in his XJ12 (German Autobahn). Actually I blew one going at about 135mph. The rear rod bearings always went under this load. I remember back then we had 20W-50 in all cars. Winter and Summer. They were SE oils and common for all apps. Later then 15W-40 was introduced and we went to that.
quote:
Originally posted by Nosmo King: I apprenticed at Jaguar's many years ago. If I remember the crank of their venerable six cylinder is long and it flexes. The main and big end clearances average over one thou more than a modern v8. Subsequently there was allot of leakage from the shells as the car was driven. Very very high flow oil pump to keep up with the leakage from the bearings. And God help you when the rings started to go ( lost heat temper from overheating ). Oil consumption would go through the roof will all the extra oil splashing about inside. 20w-50 was the oil recommended and used by most users back then and still today in my town.
 
Messages
43,648
Location
'Stralia
Is it any wonder that there are so many fitted with 350 and 400 small block chevs downunder ? (the chevs still run 20W-50).
 
Messages
453
Location
Galveston, TX
quote:
Originally posted by Volkster: About 18yrs ago, I used to work for a Jaguar dealership. I remember the only oil used in those engines(inline 6cyl & V12) was 20W50, all year 'round, regardless of temperature. If I recall correctly, this was a specification that came directly from the manufacturer. Doesn't this seem a bit odd by todays standards? What would compell Jaguar to recommend such a heavy oil across the board?
20w50 for jaguar is not too extreme. Jus' wait till you find out what Rolls Royce use in their venerated limousine engines.
 
Messages
43,648
Location
'Stralia
It's funny though, they ditch the Jag 6, and install a V-8. Then they have to cut the front springs to get the front end back down to where it belongs. I've not actually seen a ford engined one, a few old mercs with 250s in them.
 
Messages
404
Location
Palatine, IL
quote:
Originally posted by Shannow: It's funny though, they ditch the Jag 6, and install a V-8. Then they have to cut the front springs to get the front end back down to where it belongs. I've not actually seen a ford engined one, a few old mercs with 250s in them.
I prefer the six, easier to work on. Most likely more reliable too although the V8's haven't been out long enough to tell
 
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