Installation of Mocal oil thermost sandwich plate
(For Rover V8 engines with V-Belts and external gear type oil pump system. Serpentine engines with rotary vane pumps are a TOTALLY different beast altogether!!!!)

Oh, an update to this page at the bottom regarding the radiator fittings. Look for it if you haven't seen the GOOD fix for that side.
My '94 Land Rover Defender NAS was suffering from a common problem that most Land Rovers with a V-8 and oil cooler have, disintegrating oil lines. More than a few Defenders have died due to massive underhood fires as a result of these lines bursting and spraying engine oil over the hot exhaust manifolds. Even if you're lucky enough to not have a fire, the sudden loss of oil pressure at higher RPM's can mean a very costly engine replacement without the benefit of the insurance coverage that a fire can sometimes fall under. Unforunately, replacements from Land Rover aren't cheap at around $200 for the two hoses in question. That is, if you can even get them without a long wait. In my quest to find a cheaper and faster alternative, I found out a few interesting things about the oiling system on the engine, and oil coolers in general, which led to inevitable upgrades and extra parts. I consider the time and money very well spent, but figured I would save some other folks the hassles.

Right from the start, I decided that I didn't like the factory setup for the oil cooling system. In fact, I never like the in-radiator type coolers for anything. Once the engine is hot, it simply places extra demand on the radiator. As the anti-freeze temperature rises, the oil cooling ability of the radiator decreases. If your engine starts to overheat, then you might actually be transferring heat back into the engine or transmission via the "cooling" lines. For later trucks with both oil and tranny coolers in the radiator, yikes. Tranny fluid really needs to be kept cool, and I just don't think the stock system is up to the job during situations such as towing and slow speed off-roading. Since Defenders seem to have problems with overheating occasionally as it is, I have wanted to add a remote oil cooler that is totally disconnected from the radiator system. Preferrably, I want to eventually use a unit like the Setrab "Fan Packs" which are high quality oil coolers integrating their own fan. This would give me a totally separate system to help cool the engine while increasing the total cooling capacity and reducing the demand on the radiator.

The first plan was to just install a remote oil cooler in place of the existing one, but research pointed out that a big oil cooler was a bad idea without a thermostat. On a enough cold day, even the factory system can really keep the oil temp down for a while until the coolant heats up fully in the radiator. Too low oil temeratures results in the oil sludging up much quicker, which can lead to premature wear in the bearings, cam and lifters. Don't forget the higher viscosity as well which reduces flow and increases wear.

I had originally planned to run a remote thermostat inline with the oil lines, and the only trick was to figure out the threading of existing the existing fittings. Unfortunately, that idea didn't work out quite as planned, though the end result was far better I think. The main problem is tht the banjo fittings on the oil pump aren't any of the common threadings used here in the USA for oil lines. While trying a variety of AN and NPT fittings, none of which worked, I realized that the oil cooler lines were attached via a sandwich plate and not a permanent part of the oil pump.This actually made my life simpler, since I could now use a Mocal sandwich plate that incorporated an internal thermostat instead of having to use a separate unit. No extra parts hanging off anywhere, less connections to make, I was sold.


(Note: I believe that the threading on the stock sandwich plate is 5/8" UNF, but this is unconfirmed since I couldn't find the fittings I needed in that threading. There has also been mention that some stock sandwich plates may already have an integrated thermostat, but I have not yet come across one. Any specifics on this would be appreciated, pictures too if possible.)

Parts list:
From Racer Parts Wholesale
1 x Mocal SP1T oil thermostat sandwich plate : $79.99

From Pegasus Auto Racing
6ft Aeroquip 1/2" ID reinforced hose
One pair of 1/2" BSP to -10AN male/male fittings
Two 1/2" BSP Dowty type seals
Four double ear oediker clamps
Two -10AN barbed fittings for 1/2" hose
Crimping tool for clamps

http://www.eastcoastrover.com/option2.html
Info for the radiator-side fittings. Much better than what I used.
Highly recommended, and the only ready to ship option I am aware of that properly fits guys with the same radiator as mine.
Here is the stock oil lines, vintage 1993. After 11 and half years, they are rotted and look ready to split. The hardline portions are actually fine, but the rubber sections look ready to fail at any time and were making me very paranoid. After all I still have 45 payments left on the truck!

The bottom Banjo fittings, I never did figure out the threading. They aren't any of the following. -10AN, -8AN, 1/2" BSP or 1/2" NPT. They MIGHT be 5/8" UNF threading, but don't quote me on that.
Step 1, Remove oil filter. This picture shows the old sandwich plate with the filter removed. To remove the sandwich plate, just loosen the big honking hex nut where your oil filter threads on. I honestly don't know the socket size needed, but I used a 32mm socket without a rachet to loosen the adapter by hand.A deep dish socket would be best, and 32mm is NOT the correct size, but I had to use what was in the toolbox to do the job. After the sandwich plate comes off, make sure to also remove the old adapter gasket.

Remember, when you remove the oil filter and the sandwich plate, oil WILL dump out. You'll need to top-off anywhere from a quarter to half a quart depending if you needed to replace the oil filter and how much spills out.

Just a side note, if you really need to drive, and the oil cooler lines are bad. Just remove the oil cooler lines, remove the sandwich plate, and put the filter back on as normal. Without the sandwich plate in place, it's just a normal oil filter boss. Something very handy to know on the trail.
Here is the new Mocal sanwich plate with 1/2" BSP x -10AN adapters installed, and hoses too. Note the dowty sealing ring between the blue hex fitting and the sandwich plate. For any port type threading, BSP fittings need some type of face seal. Most cases the Dowty ring will be what to use, however sometimes the fittings have a chamfer in them for use with O-rings. Male and Female hose ends joining together are self sealing. I actually like the lower profile of the BSP fittings, much less space needed than NPT or SAE type fittings

This side faces is the one that faces the oil filter itself, you can tell by the flat sealing surface. It's done this way, because the oil filters themselves usually have the gaskets on them. The other side with the rubber sealing ring will face the engine. The brass fitting in the middle is what holds it all onto the oil pump.

I decided to go with -10AN on the sandwich plate because the long term plans include a real oil cooler instead of the radiator type joke in there now. When I do that, I'll be using all -10AN fittings and 1/2" hoses to hopefully give the best possible flow in the oil cooler system.

Oh, these type hose clamps require the proper type of crimping tool to install. The one I got from Pegasus worked perfect and has a two way crimping head that allows you to either crimp from the top or side of the tool. They're easier to put on than the normal screw type hose clamps, hold better, and since they expand and contract with the hose they also won't loose their clamping force within a few heat cycles like the more common type clamps do. The only drawback is they are a one-shot deal and can't be re-used. I plan on using this type of clamp much more in the future.
Another view of the prepared assembly going into the truck. I had already measured, cut and put the fittings on the new oil lines ahead of time to make installation easier. These hoses are rubber cored, but have much stronger textile reinforcement and separate outer layer. Much stronger, longer lasting, and burst resistant than the hoses coming out. They are also much more flexible, so make sure they are routed to stay away from the fan.
Here is the old sandwich plate and oil lines after removal. Note that the oil-cooler side uses a pipe and o-ring seal. There are a couple varients on the radiator fittings for Defenders and you need to check the radiator to see what the fittings on that side will be. For info on that, check this link from East Coast Rover.
http://www.eastcoastrover.com/option2.html
These guys are THE place for restoration and big work on Defenders, and make great stuff. You'll be well served by browsing their website.

Comparisons between the old and new are pretty dramatic. Not only have I added a thermostat, but the Mocal plate has much larger passages and is somewhat blended to improve flow. The oil lines are also a larger ID than those being replaced, 1/2" as opposed to 3/8" ID.
Installed, done and pressure tested. Make sure to clean everything to make leaks easier to spot later on. Everything goes on the same way that the old ones come off. This comes with a few benefits right off the bat. Not only do I have new oil cooler lines and no more worries of a massive underhood fire, but I've also improved the flow capacity of the lines and have a much easier to adapt system with known and readily available fitting sizes. Since the engine will now get up to operating temperature faster, the chance of sludging up the oil is greatly reduced.

A pleasant fringe benefit also appeared right away, and it's probably the best of all! The oil pressure stabilizes significantly faster when you start the engine. Instead of the 2-5 seconds it normally took for the oil to get to full pressure, it now takes less than one. Since most engine wear takes place during startup, it should make a significant difference in the life of the engine. This is just with the mini-cooler that came stock. With a larger oil cooler, the difference in the amount of time to get to pressure will most likely be even more pronounced over those engines without the thermostat.

Oh, and price? About $200 for everything including the crimping tool. I didn't save much money this time, but I sure as hell have a better setup now than it rolled out of the UK with. Next time the hoses need replacing, in another 10 years or so, it will cost a lot less. Since it's all universal parts, I also don't have to worry about them being available at that time either.
For people who might be using their Rover V8 in other types of chassis that don't give enough room for a filter, much less a sandwich plate, Mocal does offer other solutions. They have a replacement oil pump base #PC1 that instead of a filter boss has a pair of 1/2" BSP threaded ports to use a remote oil filter. Although that type of setup would add a lot of complexity and extra places for leaks. You would need both a remote oil filter, as well as a remote thermostat if you want to run an oil cooler. That's 6 hoses with 12 connections, and two more remote components to mount. Let's not forget the extra volume added to the system that would need to be pressurized at startup which would delay your achieving full oil pressure. No Thank You.