The standard 4.6 Litre Rover V8 has a really long Serpentine belt. It drives a lot of equipment I don’t need such as air conditioning and power steering. Mine was fitted with a 7PK2320 belt. That’s a 7 ridge flat belt, 2320mm long. With all the ancillaries fitted, the engine simply didn’t come close to fitting in the engine bay.
Without the unwanted ancillaries and a different belt route, the engine fitted snugly. The alternator sat on its factory bracket, but the complete near-side assembly was binned.
I worked out a new belt route that was roughly 1570mm long. I needed a shorter Rover V8 serpentine belt, so I bought a 7PK1570 serpentine belt from a Land Rover Defender 110, 2.5litre. 7PK belts are available in dozens of lengths and are fitted to all sorts of vehicle. The choice of lengths is incredible. You can buy a decent brand belt from your local car shop for less than £10.
Rover V8 Serpentine Belt Tensioner
I moved the belt tensioner from the driver’s side to the passenger side and made a new plate for it to sit on. The total thickness for the plate and spacers was 19.4mm.
When I swapped to the 4.6 Rover I moved the engine and box 10mm forward. The reason for this was for gearbox clearance issues. I may also need to add a gearbox spacer. The 4.0 flywheel is much thicker than the older SD1 item. I was using a slightly lightened Rover SD1 manual flywheel, but for the 4.6, I had to change to a super heavy 1998 P38 4.0 Range Rover manual item. The reason for this is the trigger wheel for the hall effect crank sensor. I plan on asking a local engineering company to machine a groove into the back of my SD1 flywheel to take a P38 trigger wheel. – Hopefully they’ll say ‘no problem’, and I can still use my lightened one. The P38 item has to weigh nearly twice the SD1 item.
I found this post: P38 Gems Manual Flywheel
The 4.6 doesn’t have a distributor, making the front timing cover shorter. Therefore, I thought I wouldn’t have any issues. However, the rocker boxes were now a little too close to the shock mounts and the oil filter fouled the chassis. Luckily, I had a remote oil filter kit that came in a box of random classic car bits (It fitted!). I will be moving the shock mounts, but that’s another story.
The 4.6 P38 GEMS cover (left) is the shortest but the oil filter sticks out sideways making it wider than the 3.9Litre cross-over cover (with distributor drive). The right cover is a Rover SD1.
The current plan is connect up all the pipe work and wiring for the engine whilst I make a couple mods to my MS1 Megasquirt. I did consider using a standard engine management ERR6645 computer with the immobiliser disabled. You can buy them on ebay for £60. But seeing as I had a MS1 Megasquirt, I thought, ‘might as well….’