To add to what Greg said, the regime of lubrication a crankshaft or connecting rod experiences is called hydrodynamic lubrication. When the engine is running, the crankshaft will not touch the bearing, instead it is lifted off the bearing by the oil and it floats on a cushion of oil. That's why wear occurs at startup, when the oil film is not yet present and the crankshaft does touch the bearing.

As the oil is pumped into the bearing, it experiences shear. There is a velocity profile that goes in an inverted U shape, where it is zero at both the contact point with the bearing and the crankshaft and at some maximum near the middle of the oil film thickness. This change in velocity is shear, and the friction created by the resistance to flow creates heat. Higher viscosity oils create more friction and heat; and heat is the enemy of oil, as it causes the oil to breakdown faster. I have seen tests with thick oil where there was enough local heat created to partially melt the bearing metal, which is obviously bad!

So part of the selection of an oil viscosity is you want it thick enough to provide an adequate film thickness to lift the crank off the bearing and ensure there is no metal to metal contact under full load, and you want it thick enough to stay in place long enough to do the job. An oil that is too thin will run out of the clearance between crank and bearing and will not develop enough film thickness. You don't want it so thick that it creates extra heat and friction, as that is wasted energy. In cold weather that can significantly slow the starter, sometimes to the point the engine won't start.

So some factors that go into the selection of the viscosity, are the oil pumps flow rate, the bearing clearances and leakage rates, loads on the components and ambient temperature. As with most things, it's a balancing act.

 

Now that's interesting. As 0w50 doesn't seem to be readily available, should we be running 5w50 in an early V12 engine?

Paul

 

I'd probably try something a bit lighter, like 0W40 and see what the oil consumption does. If it's excessive, then go heaver. What does the owners manual call for?

I used to have a 3.8 E type and unknown to me when I bought it, the block had been bored 0.030" over and one piston and rings was standard, the other 5 were 30 over. I put 5W30 in it at first and I was going through a litre every 60 miles! I switched to 20W50 and it dropped to a litre every 300 miles. After I changed the piston to match the other it went to a litre every 400 miles.

 

Got my shifter cable today and put it in. Man the original must have been really worn as as this was very tight to fit back onto the shifter arm. Just waiting for the linkage part and will be able to get it all back together completely

 

vehicle history. need to get an appraisal done before I can put it in my name should be interesting lol.

 

I've been reading posts about tire sizes but it's more about different size rims with off sets that will fit. My question is what is the highest number that will fit on the stock rims in front and back. I will probably stick with a 225/60/15 tire but I want to know if say a 275/60 would fit rear or 255/60?

 

I dunno the largest size that will fit the car.

However, the sizes you mention are too wide to properly fit on the stock wheels, which are only 6.5" wide. Jaguar itself pushed the limits a bit using a 235/60 on those 6.5" wide wheels.

When you squeeze a too-wide tire onto a too-narrow wheel the tire wont work right....and looks a little weird to boot !

Cheers
DD

 

Unrelated. Do the plastic caps come off the lug nutz? Even then tire wrench provided doesnt fit over them?

 

Mine doesn't have plastic caps, the lug nuts are all metal. Mine are 7/8"

 

Rescue119,

It seems that you have the nuts with the stainless / chrome cover caps. The nuts have a habit of corrosion building underneath causing those caps to swell. Use a fractionally bigger socket and, once, off, change the wheel nuts or considering removing the caps, cleaning the nuts and leaving them bare if in good condition.

Paul

 

Ya there are a few already broken off caps. Yes I want to replace them all. I have a 22mm and 7/8 and it doesn't fit over the plastic caps. Dont know why Jag would do that because even the factory tire change set doesnt fit lol. Thanks.

 

FWIW, If you have plastic caps they're not original lugnuts.

Cheers


DD

 

Figures lol thanks


see them here

 

At a glance, at least, those look like Jaguar nuts. A 7/8" should work fine unless there's a problem as mentioned above.. Are you sure the covers are plastic and not stainless steel?

Cheers
DD

 

Ya they are plastic / fake chrome




You can grab the actually nut and move that cover piece back and forth about 1/8th inch.

 

For future ref. Radio stuff

https://www.jaguarforums.com/forum/x...6/#post2145320

 

They look like my genuine Jaguar ones which are a very thin chrome or stainless. Tight when new, they do loosen up and you can wiggle them on the actual nut underneath.

Paul

 

Exactly but 7/8th still doesnt fit over them. Probably rusty underneath and swollen. Oh well I ended up not needing to take the wheel off for now.

 

Anyone know how I can figure out the build date of my Jag. The VIN doesnt tell me. All I know is the Car was registered to the first owner on May 26, 1988. And being from England it probably took a month to get to Canada. So maybe sometime in March or april it was built?

 

On all the Jags I've owned the build date had been on a tag in the LH front opening. Sometimes near the door hinges, sometimes on the door jamb near the latch, sometimes on the door itself (if I recall correctly)

Cheers
DD