1.6 EcoBoost Bulletproof Engine Block

The bulletproof 1.6 EcoBoost block. Why Pumaspeed went for engine liners.

As the Fiesta ST180 gets older and power outputs climb past 400bhp, the thin cast-in Ford liner, not the deck, is now the weak point. After inspecting a batch of failed engines in 2018 we stopped patching the problem and engineered it out.

What is wrong with the standard block

The Pumaspeed ductile-iron-linered ST180 block

The 1.6 EcoBoost block has a very thin cast-in liner: in other words, four tubes of iron suspended in the middle of your alloy engine block, with the pistons running up and down inside them. They are stronger than the surrounding alloy and let the pistons run with very little bore wear. We documented years ago why the deck shims were needed (see the Fiesta ST block mod kit), but with these cars getting older and more worn, and power outputs going above 400bhp, it is now the life of the stock Ford liner, rather than the deck, that is in question.

Over the final weeks of August 2018 Pumaspeed inspected seven or eight engines of varying mileage and failure. The findings were disturbing: 75% of the blocks were technically scrap, around half had cracks down one, two or even three of the stock liners, and all bar one had the terminal deck-ovalling problem. Out of all of them, only one was fit to be rebuilt as a stock-bore motor.

The solution: a proper liner, not a patch

Something had to be done to let the 1.6 EcoBoost survive the under-engineering Ford built into it. The tried and tested deck plate on top of the deck with a shim between each cylinder was never going to solve what we were seeing. The only real answer was a full liner system, very similar to the Darton liners we have used on Volvo and Honda engines.

Liner development and installation needs very accurate machinery, so Pumaspeed invested in a state-of-the-art CNC system to machine the old thin liner away and install the new unit. The liner is pressed down to a stop lip, then the block is honed to size for whichever piston you need, from the Omega at 2 thou undersize right up to the 1.5mm oversize we are looking at for added capacity. The deck is then skimmed to give a perfectly flat surface, taking the bare minimum off blocks and heads so the compression ratio stays where it should be.

The new liner is far thicker than standard and, more importantly, the cast-iron liner now sits flush with the deck and the head gasket, so it is far stronger than the old thin liner and alloy deck. We believe this is a massive step forward for the power potential of the 1.6 EcoBoost, and every Pumaspeed Blue Top motor now includes it as standard. All competition-spec motors, unless built on a brand new Ford block, are built this way from now on. Our grey car has been the test bed: with the new X57R turbo, a set of injectors and our uprated fuel cam kit it has hit 412bhp reliably, on and off the track.

Five linered blocks on the bench

Blue Top bulletproof 1.6 block →Black Top closed-deck 1.6 block →Ductile iron sleeve liners →ST block mod kit →

Tech spec: the Pumaspeed Fiesta Mk8 EcoBoost

503bhp at 29psi of boost and 22 degrees of ignition

• Engine: 1.6-litre four-cylinder EcoBoost GDI from the ST180 Mk7. Pumaspeed ductile-linered block, sleeved to suit Omega pistons (2 thou undersize). Sainz lightweight connecting rods. Area 6 ported cylinder head with standard 1.6 valves. Piper Stage 2 cams with Piper uprated single valve springs. OE Ford bearings. R-Sport cross-braced baffled sump.
• Fuel system: uprated Bosch DI injectors with roughly 35% extra flow, modified with double seals to suit the OE tip position. Pumaspeed high-flow fuel camshaft adaptation.
• Turbo system: Pumaspeed G25-550 external wastegate kit with unique reverse rotation, promoting spool from the short-runner design and lower-angle pipework. Tial 44mm external wastegate and screamer pipe.
• ECU: SCS Delta GDI stand-alone ECU, specific to Mk8 CAN data.
• Clutch: Pumaspeed ST200 Plus clutch on the stock flywheel, upgraded to a Pumaspeed single-mass flywheel and sprung centre plate in January 2020.
• Induction and cooling: R-Sport Fiesta ST180 Stage 3 cold air induction, R-Sport Pro 400 Gen 2 intercooler, Pumaspeed Racing silicone hose kit with 63mm alloy hot side and custom alloy cold side, R-Sport triple-pass alloy radiator with Pumaspeed Racing silicone hoses.
• Exhaust: R-Sport 3-inch de-cat downpipe and a modified Milltek ST180 70mm system.
• Transmission: stock IB6 gearbox with a Gripper differential, custom driveshafts and a custom Mk7 gear linkage.
• Suspension and brakes: Bilstein B14 coilovers, Pumaspeed Racing 330mm front kit with DS3000 pads, stock Mk8 rear calipers and pads.
• Wheels and tyres: 8x17in Ultralite wheels on 235/40x17 Continental Sport 5.
• Exterior: Pumaspeed graphics package, MGC-designed high-line rear spoiler, Pumaspeed low-line front splitter lip and side skirts.

Read the full 503bhp Mk8 story →Fiesta ST180 tuning →Fiesta ST Mk8 tuning →

Fast Ford Magazine, November 2019: the Mk8 with a Mk7 heart

There have been many sporting Fiestas: the Mk1 of course, with the testing-the-water 1.3 Supersport and then the original XR2, but it was the Mk2 XR2 that became the real cruise-culture icon, and Ford of Europe just kept pushing the envelope, each generation bringing a more exciting, resolved and aspirational performance variant. From the RS Turbo and RS1800 through the ST150 and on to the ST180 Mk7, it is a truism that fast Fiestas are always winners.

Fast-forward to 2019 and things get a little confused. The now-discontinued Mk7 ST180, with its 1.6 EcoBoost, was a universally acclaimed creation that won more awards than you could shake the proverbial stick at. And the Mk8 ST, with its three-cylinder motor? That dinky triple may boast similar figures to the Mk7, and the car is unquestionably excellent, as the trophy cabinet at Ford HQ demonstrates. But is this the first time a hot Fiesta has not been quite as good as the model it replaced? The simple answer is, er, no.

We are deliberately leading you up a dark alley. But that has not stopped Pumaspeed tearing the new Mk8 champ apart and retrofitting some older power under the bonnet, to turn it into the car Pumaspeed think it should have been from the start. What you are looking at is the first and only Mk8 Fiesta running a four-cylinder EcoBoost from the revered Mk7, and Fast Ford think that is quite a bold move.

The Pumaspeed name needs little introduction to regular readers; suffice to say this powerhouse of Ford tuning is no longer focused solely on Pumas. In the twenty years since the company was founded they have grown into an aftermarket colossus covering every model and a market-leading authority on EcoBoost tuning. From Zetec S models all the way up to the Mk3 Focus RS, they produce many of their own parts and supply premium components from around the world, and numerous Pumaspeed builds have featured in these pages.

“A lot of people can’t believe we’ve done something like this to such a new car”

“It all started back in February 2018,” grins company founder Tony McQuire, “when we collectively decided to build a one-of-a-kind car simply because we could. The following month this Fiesta was found on a well-known online salvage auction site; it had a broken strut, front hub and driveshaft, and the rear axle was bent. It also had minor panel damage and needed new bumpers at each end.” Tony could see straight through the damage to the massive potential within, and the little cogs in his head started spinning. The Mk8 was duly snapped up and immediately stripped down to assess the repairs needed before the team could start building it into something sensational. The goal was to have it running by Ford Fair, so there was no time to lose.

“We started by carrying out the repairs necessary for it to run and drive,” Tony continues, “and then in April we took it down to SCS Delta for exploratory ECU development after many, many discussions about the engine. By June we were deep into creating a very expensive, one-of-a-kind motor.”

The specs are formidable, because it was never the intention simply to fit a stock ST180 four-pot and leave it there. This was always going to be a radical head-turner, a master of the double-take when the bonnet is lifted, so the team made sure this particular four-cylinder EcoBoost pushed all the right buttons. The firm’s proprietary ductile liner conversion prepared the block for 2-thou-undersize Omega pistons, while a set of Sainz lightweight rods were fully balanced to suit the 8,750 to 9,000rpm redline. Piper Stage 2 cams went into the ported head, and fuelling was improved with larger injectors and the Pumaspeed Full Flow modification for 20% more fuel delivery. There is a variety of R-Sport kit too: the air filter, triple-pass alloy radiator, Pro 400 Gen 2 intercooler and de-cat, the latter working with a Milltek exhaust mildly modified to fit. After all those long conversations, SCS Delta’s ECU has been fully integrated into the stock Mk8 loom, so the standard dash keeps all its functions, and all the ones and zeroes have been corralled into a mighty 440bhp on medium boost, or 503bhp on high boost.

These are staggering figures, thanks in large part to Pumaspeed’s supremely clever reverse-rotation G25-550 turbo set-up. “This was designed from the ground up to lower spool times with its unique reverse-rotation exhaust housing,” Tony explains. “It allows shorter primary pipe runs from the cylinder head to the exhaust housing, so we are looking at 2 bar of boost at only 3,500rpm and a massive rev range of up to 8,250.”

Naturally there is more to this car than an engine. The extra cylinder may be the party piece, but the entire car has been engineered to cope with the power and deploy it. The transmission, with its custom gear linkage, gained a Gripper LSD to apportion power through the custom driveshafts, and the factory suspension gave way to Bilstein B14s. The spectre of the Mk7 ST walks tall through the build: the older car initially donated its front brakes, since replaced by Pumaspeed’s own 330mm four-pot kit, as well as its ST180 front seats. It would have been fun to wrap all this magic up as a sleeper, but as a demonstrator it makes far more sense to look suitably outrageous, hence the almighty rear wing and full Pumaspeed graphics package.

“The Mk8 ST platform is an absolute dream to own and drive,” Tony assures us, “and dare I say it is better than the Mk7 in every regard. Now that it has the four-cylinder engine at its heart, it has the muscle to go with the chassis. We use its 440bhp as a daily driver as well as a track toy, and it is perfect for both.” What Pumaspeed have created is a very appropriate continuation of the long line of hot Fiestas: a scene-shifting monster in some respects, but very much a trailblazer. It is the first Mk8 road car to run a four-cylinder EcoBoost, and given the performance and potential on display, we do not imagine it will be the last. Fast Ford Magazine, November 2019.

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