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1994 NAS Defender 90 Soft Top
4.6 V8 install and Upgrades

This Defender 90 has come to us from Florida for a new ECR 4.6 V8 and some upgrades and repairs. The 90 has over 130,000 miles, so there are a number of things to take care of, but we'll be getting it back in shape and giving it the power it has been lacking with a new ECR 4.6.

The first step in getting the D90 back into shape it to rip out the old 3.9 and get the engine bay cleaned up and ready for the new ECR 4.6. In the image above you can see we have removed the engine and are giving the engine bay a good once over. The Rover is from Florida so there isn't any real rust, but there is lots of mud and debris.

Here you can see the old 3.9. It has definitely seen better days. It is leaking from just about every gasket and the compression figures are terrible, as is the oil pressure, but in its defense it was still running. The next step is to remove the ancillary parts from the 3.9 and start cleaning up what we can, and replacing what we have to.|

Speaking of cleaning up... the image above shows the LH side of the intake manifold. What you see here is about 3 inches of solid mud and debris. If you off road your Rover in mud that is a lot of fun, but unless you want to pay big repairs bills make sure you clean the mud out when you are done having fun. Remember for every few minutes of fun in the mud you are going to need to spend a few hours cleaning. Another mistake on this Rover is that a previous mechanic used fuel line for the coolant hoses on the 90, so the hoses are stiff and rotted. Rubber hoses for fuel, vacuum and coolant are all made differently and need to be used in the right application. A hose is not a hose, but this customer got "hosed" by some mechanic that thought so.

The RH side of the intake has lots of mud as well, but this time it is soaked in oil from a leaking valve cover gasket. It will take quite a bit of time to get these parts cleaned up and ready for the new 4.6, but most of them will survive. Anyone who tells you the Rover V8 just "leaks" is dead wrong. There are numerous updated seals and techniques to seal up a well running Rover V8 so that your engine bay is clean and your engine lasts a long time. Just saying "It's British and is supposed to leak" is a lame excuse for not doing the job right. They don't need to leak, and our installs don't leak, don't settle for less.

This image shows the oil pick up tube in the 3.9. We've flipped the engine and removed the oil pan and this is what we found. The oil pick up is nearly clogged solid with crud. That doesn't do good things to your oil pressure and your engine. The reason for this crud... lack of oil changes and PCV service from a previous owner and lots of moisture in the engine. Notice the extent of the rust on the oil pick up (the brown blotches under the oil film) that means bad things for this 3.9. Its ready for the scrap pile... bring on the 4.6.

While the Defender 90 is here at ECR the customer has decided to upgrade to 4.11 gearing and a roughly 32" tire. We have pulled the axles, removed the differentials and are working on swapping out the 3.54 gears for the 4.11s. These will correct the highway RPMs for the larger tires and will give the D90 a better crawl ratio when off roading. With 32s and the stock gearing the 90 would be a little too fast off road when in low range, and slow is the name of the game.

Here you can see that the rear differential, now out of the Rover, has been stripped down for the 4.11 install. We go back through and set the pinion depth, backlash and pre-load all with factory tools and the most accurate of gauges. This assures that your gears will be smooth, quiet and last a long time. The Rover has front and rear ARB lockers (a great addition) and we'll check over all the o-rings and make sure they are in top shape before we re-install them. At 132,000 miles some of the parts in the differentials needed to be replaced, but they will be good to go for a long time to come.

In the image above you can see the parts from the old 3.9 have been cleaned up and installed onto the new ECR 4.6. The assembled engine is now ready to go back into the D90 to give it the power that it was lacking from the factory. Next we'll get the engine back in the engine bay and remove the EFI computer from inside the Rover and update it with a new chip to get the most out of the new engine. Some people still say that a 4.6 can't be installed in an early Rover, but as you can see above it can. We've been installing 4.6s into earlier Rovers and Defenders since the 4.6 was introduced. Don't let anyone tell you it can't be done, our ECR 4.6s come ready to bolt into your early Rover application and they include the needed conversion parts to make them work, such as the crank spacer, computer chip and oil pan, all at the price some places charge just for the engine alone.

Here you can see the new GBR 4.11 gears installed with the customer's ARB air lockers in the diffs. These units are ultra tough and will make the D90 run correctly down the road with the planned larger tires.

Speaking of larger tires... here you can see the 32" Good-Year MTR radials that we installed on the Defender 90. We have mounted them on the customer's alloys and with the 4.11 gearing we just installed the D90 will run and drive great. The MTRs are a great tire for the people who need good on road ability and good off road ability. They are a good balance between the two.

Here you can see the 4.6 now installed in the Defender's engine bay. It looks pretty stock in there (that's the point) and can be serviced by your local dealership or specialist. The 132,000 mile Defender 90, now with the heart of a brand new balanced 4.6, will run with the best of them and be ready to tackle anything. The 4.6 install might look complete in the image above, but to successfully do a 4.6 install you need to address one more thing... the EFI computer.

The image above shows the Defender's EFI ECU. We have removed it from the vehicle so that we can change the main computer chip. The red arrow points to where we have removed the stock 3.9 chip and installed our 4.6 conversion chip. Unlike other conversion chips, or some that even use the Rover 4.2 chip, this one works perfectly with our balanced 4.6 and it retains all the positive running characteristics of the stock chip. Smooth idle, excellent low end for off roading and more are all still on tap with our chips and 4.6s. Our chips also retain all the factory style on board diagnostics so that your check engine light still will alert you to an EFI problem. Most of the UK chips do not retain this feature and you'll drive around for months wondering why performance is down and your mileage sucks. Our 4.6 installs are complete from top to bottom and everything needed is sold with our engines, including these correct EFI chips.

After the engine install we needed to look at a number of items on the D90. With high miles and a few owners the D90 was suffering from a lot of poor work over the years. One of the worst systems was the wiring. In the image above you can see that to chase down all of the wiring problems and get everything into shape we had to basically gut the dash. Each time something was added in the past more and more wires started to be connected to stranger and stranger places. Once we removed the add on wires (we removed about half a garbage can of extra wires from the D90) we were able to start over and do things the right way.

One all the repairs to the wiring harness were done, and the aux. systems added to the Defender correctly we were able to button up the dash and make it look this clean and correct. All the roof lights, CB, rear work/reverse lamp, driving lights, lockers and such are all still controlled easily, but the goofy switches are gone and the simple wiring is now easy to trace if need be and easy to service in the future. We then added a set of Optima batteries to keep everything going with plenty of juice.

The D90 also needed a ton of small work orders completed that we don't have space to detail. Items that ranged from upgrades like adding the key-matched tailgate lock you see in the image above, (the 1994 D90's didn't have these and it is really a pain to lock the rear gate without the upgrade) to wear items like new brake pads and shocks, to the correction of things that were just not installed right over the years. We completed a full evaluation of the Rover and completed everything the owner desired.

After going through those work orders the D90 is now ready head back to Florida for lots of fun in the sun. The D90 is now ready to hit the trail with its 4.11 gearing and new Good Year MTR tires and will make short work of anything in its path with the added power and reliability of the ECR 4.6 engine. If you need major or minor service for your Defender contact ECR. We'll be happy to bring your Defender up to your exacting specifications.