V8 AWD MK2 Sedan

[Nev Bertwistle]

As the title suggests I have a new project underway now to slot the Volvo V8 engine into a MK2 Focus sedan. The car I’m using is the one I built 4 years ago and was Australia’s first XR5/MK2 Focus AWD conversion. It’s done over 30000km of incredible motoring and really confirms the value in the AWD conversion. My inspiration for this build is THAT photo of the magenta S40 in Sweden which I understand was built by Volvo (apparently there are two?). According to legend there is also a C30 V8 built by Volvo in Arizona US but that’s about all the info I can find on P1 platform V8 conversions.

The brief is simple – take one B8444S engine, mate it to the M66 AWD gearbox and bolt that into a Focus with the AWD conversion. The V8 will get a full performance build with the displacement increased by using a Yamaha outboard crank which in turn will require custom rods & pistons. The top end will get similar custom treatment and we’ll ditch the Volvo inlet for 8x ITB’s. An ECU Master EMU Black Pro will run the engine and give me control over the Haldex at the rear. There will be front & rear Quaife LSD’s, P2 transfer case and rear diff and a bunch of mods already in the car. To date I have the car, two V8 engines and drivelines (one XC90 and one S80), the Yamaha crank, multiple AWD components and a crazy engine builder who is super excited to build a custom Volvo V8.

There are actually two main projects here - the engine build is one and having it installed in the car is the other. I'll put both of them in this build thread and switch between the two as progress permits, so sorry if it comes across a little disjointed.

[Nev Bertwistle]

The starting point is the Volvo B8444S 4.4L V8 engine, which is decoded as follows:

B - gasoline
8 - no of cylinders
44 - displacement (4.4L)
4 - no. of valves per cylinder
S - naturally aspirated

Volvo designed the engine and had Yamaha in Japan do the manufacture. It first appeared in the 2006 XC90 and later in the S80 sedan and ran up until 2010. The fact that it was to sit in engine bays that accommodated T5 and 6cyl engines (transverse mounted) meant that the V8 had to be very compact (it only has a 60 degree V). Standard output was 232 KW (315 HP) and 440 Nm (325 lb ft) with a relatively low 190 kg weight. Bore x Stroke is 94mm vs 79.5mm to give 4414 cm3.

Yamaha took the design and went on to produce outboard motors from it. They turned it on its side, changed the heads so the inlets were from the sides and the exhaust can out the center, changed from chain drive to belt drive for the cams, and increased the displacement to 5.3L by increasing stroke to 96mm. This was the F350 (so called because it made 350hp) and they did a larger 5.6L version by going to a 96mm bore. This was the XTO 425 (extreme offshore 425hp). There's a bit of chatter on Volvo forums about using the boat crank in the car block as the general consensus is that the two motors share a lot of common componentry, but the reality is that they are very different engines. Apart from the same bore spacing and size, there is virtually nothing in common between the two.

There was also the V8 Supercar engine which was 5L and this was by an 88mm stroke with a 96mm piston. All engines were built by Polestar and supplied as crate engines to Garry Rogers Motorsport. The only parts in common with the road engine were the block, heads and timing chain.

[Nev Bertwistle]

Having removed the S80 V8 engine it was time to strip it down so as to see what we are working with. Here's some progress shots of the engine as it was disassembled. As you would expect from Yamaha it's a beautifully built engine.

[Nev Bertwistle]

My aim for the engine is to build a high performance version hopefully with over 500hp but to do that will require lots of work. Unfortunately there is zero info on the net about this engine and performance parts are non-existent so everything we do here will be custom. The brief is to start with the Yamaha outboard crank to increase the displacement to 5.3/5.6L. If we can get that to fit then we'll need a piston & rod combo to suit. If we can't get anything off the shelf it will be custom made. That displacement (extra 16mm stroke) will mean the block height will be too short so we'll make torque plates to cater for the extra length (calculated to be around 22mm) and fix those to the block then liner the bores to suit the pistons.

The extra block height will affect the timing chain so we'll make a longer one to suit. Cams will be custom grinds and the heads will get the once over to get the best flow we can. For induction I'm throwing away all the Volvo gear and going 8 stack injection, all of which will be custom made. Same for the exhausts - new tubular headers etc. I'll use an EMU Black Pro to manage it all and also control the Haldex in the rear.

I looked around for a while and finally found an Yamaha F350 boat crank in Perth so bought that and a matching rod/piston combo so I could see how it would work together. Comparing them to the car components was very eye opening

Here are the two cranks side by side (nitrided boat left, car right).

Careful measuring shows both big end and mains differ in both diameter and widths. Not much, maybe a mm or two here and there but enough so that you can't sit a boat crank in a car block. The counterweights are larger in the boat and the crank ends are quite different. Initial thoughts are that the firing order may be different but we'll check that as we get into the build.

Note the extra length on the boat crank (which would normally be the flywheel end) to cater for the belt drive timing setup. This will all have to be cut off and the end reworked to take a flywheel.

[Nev Bertwistle]

The rods & pistons were also quite different. The car rod is steel with a full floating cast piston and has a centre-centre length of 138.5mm. The boat rod is sintered steel with a pressed pin forged piston and has a 155mm centre-centre length. The boat forged piston is beautifully designed.

Car piston

Boat piston

[Nev Bertwistle]

First task is to see if we can get the boat crank to sit in the car block. The mains are approx 1mm smaller in diameter so the machining required was to the journal widths. Each main journal was measured and the crank put in a lathe where somewhere between 0.020 and 0.090" was removed from each. While the journals were now correct, to fit the counterweights also required some metal to be removed from their sides to reduce thickness. Note these are just rough changes to prove we can make it fit. There's a lot of final finishing plus re-nitriding to do before we put this in an engine.

Crank in lathe

Machining one of the main journals

Another journal plus you can see where the counterweight has been machined on the inside

After lots of work we now have a crank that sits in the block which is in itself a major achievement.