RPi Rebuilt 4.6 Long Rover V8 Engine GEMS/Thor (built to order)

RPi Rebuilt 4.6l Long Engine to suit Gems and Thor EFi systems.

Please note all RPi engines are currently built to order and lead times can vary depending on specification and the number of engine orders we receive. Please email info@v8engines.com to find out the lead time for your chosen engine specification. 

What vehicles does this engine fit?

This engine is built to accept either Gems or Thor EFI depending on your selection. If you are running an earlier EFI system or carb along side a distributor setup then please visit our other 4.6 listing that covers this setup.
The Gems and Thor EFI systems were installed from Factory in some NAS spec Discovery 1’s and Defenders (Gems). The Defender 90 50th(Gems), the Morgan +8 4.0 litre (Gems), all Discovery 2’s (Thor) and all P38 Range Rover (Gems and Thor).

The RPi standard
Built by Holly, our engine builder with 30+ years Rover V8 building experience, a long engine is our most commonly chosen level of engine build and includes a block, crank, pistons, conrods, cylinder heads, camshaft kit and rocker assemblies. All that’s left for you to do is bolt on your covers, ancillaries, ignition, fuel system and fit it to your car. This means that you can be sure cam timing is correct, tappet pre-load is set correctly and the heads are bolted down to the correct torque and in the correct sequence. We offer a service to inspect, clean, paint (where necessary) and fit any ancillaries etc that you send to us too either with or without your exchange engine along with the ability to bench run the engine on site to carry out all base settings and break in the cam etc. Please contact us if this is of interest.

A block from our selection of core material is chosen and chemically cleaned to ensure it’s free of contamination inside and out. We check the threads to ensure that they’re in good condition and repair any that aren’t. The “big thing” when it comes to 3.9, 4.0, 4.2 and 4.6 litre Rover V8 engines (94mm bore) is cracked blocks and slipped liners, which it is worth noting at this point are not the same issue. We pressure test all of our 94mm bore blocks with no liners installed, if we find a crack then the block is rejected. If the block passes, it is machined and brand new top hat liners are fitted. The important thing to note is that top hat liners do not cure a cracked block, the top hat only stops liner slippage. If you would like to learn more about this subject, please see this comprehensive video on our YouTube channel.

The crankshaft will be reground/polished, and the appropriate bearings fitted (the size of which will be detailed in the build spec sheet we send with every engine build). New stretch big end bolts are used, and new bearings fitted throughout including new cam bearings. Brand new pistons and rings are of course fitted. 

The cylinder heads go through our rigorous process of cleaning and inspection. All our cylinder heads have the faces skimmed, are fitted with new valves, new bulleted valve guides with neoprene seals, new valve springs and new core plugs. 3 angle valve seats are also cut as standard, and all valve heights are set the same across the head. The rocker assembly is built up using reconditioned Rover rockers (we won’t touch aftermarket rockers with a 10-foot pole) onto brand new rocker shafts and of course a set of new push rods. Heads are torqued in place correctly with composite gaskets and brand new stretch bolts

Supplied with all the gaskets required for us or you to compete the engine with your original covers and ancillaries.

Head options
Stage 1
cylinder heads feature all of the above plus the valve seat choke opened up slightly and then have all edges smoothed inside the ports to allow for better air flow through the head. Piper valve springs are installed along with the bulleted valve guides and neoprene seals. 3 angle valve seats all cut to the same height and once the face is skimmed the head is CC’ed. Better air flow translates into a more efficient engine which in turn of course an increase in both torque and bhp. Although only a mild upgrade they make for usable gains in torque.

Stage 3 heads are fully ported on both intake and exhaust side. Stage 3 valves are installed and the valve seat choke opened up to match. Piper valve springs are installed along with the bulleted valve guides and neoprene seals. 3 angle valve seats all cut to the same height and once the face is skimmed the head is CC’ed. We have been thoroughly enjoying the combination of a stage 3 4.6 engine with a mid range cam (such as a Piper 270) in four-wheel drive vehicles. The natural torque of the 4.6 is enhanced further with the upgraded heads, while the mid range cam keeps things nice to drive on the road and puts the power band right where it will be most used, making for a very relaxed, unstressed drive on cruise whilst also having excellent throttle response and “get up and go” when you want to get moving. Of course this combination does also work very well for two wheel drive vehicles and if you want to go a step further for as much top end BHP as sensibly possible (without going over to Merlin stage 4 heads) then the Piper 285 cam is available too.

Camshaft choice. – All camshafts are the short nose version and are compatible with all our head options but please see 285 notes.

Piper Torque max
Like the name suggests, this camshaft aims for torque at the bottom to mid rev range. Our base camshaft and suitable for use with your EFI system if you are not wanting to enhance things further with our Gems or Thor ECU remaps.

Piper 270
A power increase in the mid rev range with a good increase in usable torque and bhp. The Piper 270 is great for the lighter Morgan +8’s with the Gems engine or a good upgrade for any 4wd cars using an auto gearbox seeing as the torque converter allows the rpm to slip up to the mid rev range. Also advisable if in a 4wd you have a manual transmission but like to keep the rpm in the 2500 to 4000 rpm range. Still offering a great idle so no issues at lower rpms either. ECU remapping is essential when using the 270 camshaft to ensure fuelling is correct, please see the fuelling section of this website for more info.

Piper 285 – Proceed with caution
The power band gets shifted even further up to the top of the rev range, pushing for higher BHP figures, but getting to the stage of detracting from torque at the lower to mid rev range as well as starting to introduce some lumpiness in the idle. In other words this is getting close to a race camshaft. If the majority of your driving is on the road, we would recommend sticking to either the Piper 270 or Torque max.

Spec list :

  • Pressure tested, top hat lined block
  • Chemically cleaned and all threads checked and helicoiled were necessary
  • Reground/polished crankshaft
  • New bearings throughout including camshaft bearings
  • New pistons and rings
  • New core plugs installed
  • RPi remanufactured cylinder heads fitted – please choose standard / Stage 1 / Stage 3
  • Camshaft kit installed and tappet pre-load set – Camshaft options listed
  • Rocker assemblies installed with new push rods
  • Brand new head bolts used along with composite head gaskets
  • All gaskets supplied to enable us or you to build the engine up with your covers and ancillaries etc.
  • All assembled by our world-renowned engine builder Holly with over 30 years experience of assembling Rover V8 engines.

Other items required to build this engine up ready for your fuel and ignition system – This might be obvious to many but some of these items are often overlooked and yet are so important to do the job right

  • Your original timing cover - paying close attention to its internal cleanliness
  • New oil pump gears
  • New water pump
  • New oil filter and oil – Valvoline VR1 20/50 mineral oil is and always has been our oil of choice.
  • Your original sump / baffle and strainer (oil pickup) - paying close attention to its internal cleanliness
  • Your original rocker covers and baffles – paying close attention to their internal cleanliness

Fuel / ignition

We supply both fuel and ignition systems most of which can be seen through the relevant shop sections linked below. Should you wish to have use install your fuel and / or ignition system please contact us so that we can discuss it with you to ensure its correctness and our abilities to bench run the engine with what you have supplied should this be an option you want to take.

Fuelling: GEMS
Fuelling: Thor
Magnecor leads

An exchange surcharge applies to all RPi engines. Please select using the menu above to tell us if you are sending your engine in exchange. Please email us on info@v8engines.com for our full exchange details with regards to cross bolted engines as pricing varies depending on the condition of the core material you may be exchanging. If selecting the zero rate surcharge option this assumes that your exchange engine is 100% suitable for exchange.

Fitting your covers, ancillaries, fuel system and ignition / Bench running of full engines.

Selecting the “BUILD WITH MY COVERS” option means we will clean, inspection, paint where necessary and bolt to the above engine your covers, ancillaries, fuel and ignition systems.

To be able to bench run the engine for you we will need to either have your covers and ancillaries, fuel and ignition systems (in working order or having previously discussed what needs doing to them) or be supplying these parts an addition to the above long engine.

If you are unsure as to which options suits you best, please email info@v8engines.com

Weight 115kg