Diff oils / Coolant system pressure

[stephen low]

Hope some one can answer a couple of questions I have.

What capacity and oil type is recommended for the Jag LS diffs?

I have no idea what state the oil is in the diff of my s/h kit so am looking to replace it to be sure.

I presume it is simply a matter of removing the lower square bung to empty and filling via an allen key? headed plug from the top?

Any advice on this would be great.


Also am looking at what sort of heater I should put into the car. Was favouring an old round Smiths, Bosch or similar variant, but have heard that the coolant pressures of new engines, an AU in my case, may cause the core in such an old heater some grief to the point of failure.

Have I been fed a line here, or is this possible, due to increased pressures or simply the ageing core in an older style heater?

Please explain, as Ms Hanson would say.

Cheers

[Rebel1]

Stephen, The Jag powr-lok (limited slip) diff require special oils. From the Jag manual these are listed:

Castrol Hypoy L.S.
Shell S8096B
BP Limslip 90/1
Mobilube 46

Draining is via the bung on the underneath of the diff. Usually has a square protrusion for the spanner.

Filling is via the tube which protrudes from the back cover. This tube also sets the correct level of lubricant.

Cheers

[stephen low]

Thanks Rebel1

The tube at the back is like an upright L but seems to have some sort of cap on it. Do you just keep filling until oil hits the top of this tube?

I thought the tube some form of breather, so if you fill it right up, how does it breath?

Cheers

[stephen low]

Sorry do you also have a capacity number, how many litres?

[Rebel1]

Stephen, sorry...bum advice...filling is via the filler plug on the back cover which is below the vent tube.. Sorry for the bum advice but because my diff is so difficult to get at I have a tube fitted where the filler plug is to help in changing the oil.

The vent tube should be pointed upwards if fitted properly and should have a cap on it. The rear cover plate has internal baffles which prevent oil from escaping from the tube but it should point up to prevent any minor oil leaks from venting.

Cheers

[Rebel1]

Capacity is said to be 2.1 Ltrs.

Cheers

[Rebel1]

Sorry mate....was a bit busy there for a while.

Regarding heating systems, I've used the 50615-VUH from vintage air. see this catalogue and go to page 25 for the mini heaters.

http://www.vintageair.com/catalog.asp

Their Melbourne agent is: TCR CARPONENTS, FACTORY 5, 21 BURGESS ROAD, BAYSWATER, MELBOURNE, 3153. Tel: 03 97203006

There are quite a few other heater units and maybe some-one else will comment further.

One thing to be careful of .... If you have alloy heads make sure the heater doesn't have a heater coil made from brass or copper tubes or even steel tubes coated with a copper or brass coating.

You will invite a bad case of electrolysis if the heater has any yellow non-ferris alloys.

Cheers

[stephen low]

Thanks again Rebel1, had seen another fill point when I had it at go-kart stage but had forgotten with the body on for so long now. Obviously should have done the oil change back then. How often are you changing the diff oil?

Engine is running the cast iron specials, forgotten the name, so no need for electrolysis worries, will have a look at the vintage air options. What did your heater cost?

Cheers

Steve

[Rebel1]

Stephen, the recommended interval to check and top up the diff is 10,000 Klm and to change the diff oil at 20,000 Klm.

Thats a longggg time in the life of a cobra.

Can't remember how much the heater cost..but it comes in a kit with wiring harness, switches etc. The model I have fits neatly under the dash and has two outlets for the demisters and a vacuum operated trap door for interior air.

The motor is 3 speed and I swear that it'd blow a hole in your windscreen on full.

Give TCR a ring, I believe they carry them in stock....very popular with the hot rodders.

Cheers

[sambo]

I'm resurrecting this thread after checking out the Vintage Air units online. Has anyone fitted the newer "bi-level" heater model no. 50616-VUZ? It's cable rather than vacuum operated and allows heat to be blended between dash and floor (handy for those in the southern states!).

Here's a PDF link.

[Rebel1]

Sambo, as you have read on this thread I have the alternate model with the vacuum trap door. I have done away with the vacuum motor and fitted a push pull arrangement.

Both of the vintage air units work the same way..... either defrost, in which case all air is directed to the screen or interior heat in which case air comes out of a trap door and from the defrosters.

I think the unit you refer actually prevents defrost air when you direct to the floor.

In either case, they are bluddy good units. Way too much air to the defrosters. So much that I considered redirecting one of the defroster outlets to somewhere else and put some sort of butterfly valve in that hose.

I got the unit I did because it is just a little more compact that the one you refer.

Cheers

[sambo]

Thanks Les. Yes I'm wondering how the slightly larger (newer) unit will fit... do you know how the Harrison and RMC kits compare with regards to space between dash and firewall? Aren't they similar in many respects?

I might have to dust the cobwebs off the garage padlocks tonight and get the tape measure out - by torch light! New house/garage is less than 3 months away... not that anybody's counting.

[stiffy]

SAMBO,

New house/garage is less than 3 months away... not that anybody's counting.

I know how you feel Sambo, I get my new project at the end of the Month

Then the fun starts with the neighbours and Council

They dont think I need a 10 Car garage with 4 hoists....
They thought I was going to start a mechanical business from home......

UNTIL I SHOWED THEM MY HANDS

They still aren't happy.....

STIFFY

[Rebel1]

Originally Posted by sambo

Thanks Les. Yes I'm wondering how the slightly larger (newer) unit will fit... do you know how the Harrison and RMC kits compare with regards to space between dash and firewall? Aren't they similar in many respects?

The bodies are same, dunno about under the dash tho.

I actually remolded the front part of my tunnel to allow more room behind the dash. The RMC has acres of room behind the engine but very little behind the dash.

[Rebel1]

Originally Posted by stiffy

They thought I was going to start a mechanical business from home......UNTIL I SHOWED THEM MY HANDS

They still aren't happy.....

STIFFY

Or a bordello ... those lifts can be pretty kinky if ya know how to use em.

[sambo]

God help us if you two ever go into business together!

[Rebel1]

Originally Posted by sambo

God help us if you two ever go into business together!

Who me? .... nuh, I've led a very sheltered childhood.

Besides, stiffy has a longggggg way to catch up to this ole fella.

[Outwest34au]

Hi,
electrolysis really is an electrical reaction between two dissimilar metals accelerated by and electrolytic solution such as water, or any liquid really, some more a reactant than others, varying with salinity or acidity as well.
Alloy heads have been on cast iron blocks for yonks and did/ do still utilise copper heater cores. (price of copper slowing that up tho)
Some engines such as Datsun 200B (L20 I think) and Mitsubishi sigma (circa 4g54 and etc) are very renowned for their head munching ability. This can be corrosion and electrolysis with hard water. Other vehicles you may have owned in the past may have chewed away thermostat housing or the heater outlets on the water pump.
There are several ways to minimize electrolysis.
The first used and then traditional method was to supply a sacrificial anode, which is a earth point for the reaction. Thermostat housings are (were) pretty quick and easy to replace so it was often made out of an appropriate (shi*ty) material and died for the cause. A cheap sacrificial anode to prevent a alum. fishing (tinny) boat is to hang an old carby off the boat.
The next more modern method is good coolant. Coolant is more of an art nowadays, with ethylene and propylene (and prob many others) coolants are more made to suit an application now, much like engine oils. From watching them evolve over the years you can see a good coolants results when you dismantle an engine. Water galleys are clean because they have had a nice coating on them.
Dare I compare it to spray on non stick for fry pans?
Water filters on engines heavy diesel engines are often impregnated with 'units' of DCA. These engines might start with a DCA level of, lets say for eg, 12 units. So, we get our theoretical engine in a theoretical tractor and set it to work, after about 500 engine hours the heat and movements in the engine reacting on the coolant has depleted the DCA level to 8 units, you can easily measure this with a refractometer or use a paper dipstick much like a urine drug test strip. Screw on a new filter of 4 units (they come in different numbers to suit) and all's back to spec. You can pour a 500 ml bottle into the coolant system to replenish it also.
Without DCA coolant protection the liners in an engine may end up with pin holes in the side and water leaks into the piston swept area. John Deere 40 series tractor used to do it so close to 10,000 engine hours you could set your watch by it.
The pin holes are not caused by corrosion or electrolysis however, they are caused by cavitation, which sadly is a whole other encyclopedia, but to cut a long story short(ish) the up and down reciprocating thrust naturally produces some sideways thrust on the cylinder walls, they shake like sh*t and get vacuum pockets beside them and the water as they seperate momentarily. As the vacuum implodes it focuses to a final point of impact that "chips" a little bit of metal out of the side of the cylinder bore on the water jacket side. These eventually eat thru and a re-sleeving of some sort is required.
Coolants ain't coolants, they are pretty vital and should be maintained depending on your needs really, if you had a pool I'm sure you'd Ph it or whatever pool people do.

I also agree that old can also be corroded, I know my old man and his mates never had the cooling system preservation options we have now. Another validation for the comment you heard is probably in the fact that earlier cooling systems often used pressure caps around 7 - 11 PSI which eventually standardised on 13 PSI for a while. Older Smiths systems are brilliant heaters as used in many of the Rootes Group. BMC etc cars. Good olden day stuff, where an overkill was the way to go and quality was affordable. Probably a good choice to source a semi-freestanding unit for those that take the donor car route like me.

I got some unfitted funny asian produced heater unit with my roller, reminds me of some Nissan Cedric item for some reason. Gonna be a ***** to mount, dunno why we bother , it's Queensland, who needs a heater

Sorry people, I'll try not to do it again.
Note to self : short mate, SHORT FFS,