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My Zetec Turbo Engine


Making a Zetec Turbo Engine..and fitting it into an SS1

As my shopping list is now nearly complete, and the first dummy build is just about done, it's about time to put something down in writing - with a couple of pictures to try and explain my madness!

The Engine

The bare engine is currently a stock 2.0 Mondeo lump with an Escort sump (read front sump) and its corresponding pick up pipe, the obligatory Escort water pump and ARP con rod bolts (the standard ones are the only real weak point on a Zetec for any engine approaching 200bhp).  Compression ration will be about 8.3:1 with a 2mm stainless steel decompression plate and a standard Ford head gasket (it would have to be a 3mm one if I used the Focus RS Steel head gasket as its much thinner).  At the moment I should be able to get away with the standard pistons which seem to be able to stand 250bhp without any modification.

Flywheel & Clutch

I have a basic choice of 3; standard Escort Zetec (needs a Zetec clutch), CVH EFi (allows the use of a Escort RS2000/Pinto clutch as per original) or an RS1800/2.0 Mondeo one.  The Escort Zetec one uses a 220mm unit; the CVH EFi is 215mm and the Mondeo one is a 240mm unit.  Trouble occurs when the conversion comes to match it to a clutch suitable for RWD gearboxes.  As the clutch fork angles are different for FWD Ford gearboxes, this apparently gives a short motion/very stiff clutch - not ideal for road use.  Hence my desire to try and fit a standard(ish) RWD clutch.

Uprated clutches are readily available for the 215mm setup to cope with high power Pinto engines (RS2000 etc), but once over 200bhp is mentioned then you have to go to paddle clutches which are known for their agressive nature.  Not really a problem on a track, but not much fun driving through town during rush hour.  The same problems come with the 220mm units, but with the stiffer actuation to start with.

As soon as the 240mm flywheel is used, the standard applications are V6 Sierras and Granadas and Sierra Cosworths which seem to use the same mounting holes.  By using a V6 clutch to start with (2.9 Granada, ebay, 10) I still have the possibility of going up one step to a Cosworth clutch.  With about 200bhp coming from both engines, I hope that the stock V6 one will survive long enough.

Buying a Granada 2.9 clutch also gives me a new release bearing for my intended gearbox - a Ford MT75 unit from a late 2.0 Sierra.  Advantages are that the gearbox appears safe for 300bhp (the Type 9 gearbox dies at much above 200bhp and has already done 100,000 miles with the 1600 turbo trying to kill it), plus I get synchromesh on reverse as well.  Could be handy for autotesting...  The gearbox alas has a dirty great rubber coupling stuck on the back of it which I don't yet know if it will fit in the SS1 chassis.

Turbo and Exhaust

I've ended up deciding on a Focus 2.0 tubular exhaust manifold (standard!) and a Garret T25 turbo from a Saab 9000.

There are a few reasons; the manifold is steel so can be easily modified, is very compact, exits about level with the bottom of the head and is also a centre exit.  The turbo i've got from a Saab should give a quick spool-up time at the bottom end, although I might be limited with maximum boost at the top end.  I don't intend using more than 1 bar boost anyway (hence the relatively high compression ratio and standard pistons), and should still be able to get near 250bhp.  The Saab turbo also has an axial outlet from the turbine which makes for easier exhaust manufacture, being a single 2.5" pipe rather than having to find an exhaust elbow which exits at a suitable angle.  The current bit of pipe fitted is from the Saab downpipe; the other pipe is the old one from the Escort T3 when fitted to the old CVH engine.

Inlet manifold and Induction

I'm still persevering with the Rover inlet manifold, having had it welded to the Zetec's injector sandwich plate.  This avoids me having to pay 100 for an adaptor plate, but also allows me (should I need to) to run 8 injectors (2 per cylinder).  What some people don't realise the problem isn't getting injectors big enough, but small enough for the engine to idle properly.  Ford actually homologated an 8 injector setup for the Sierra Cosworth RS500, and many high power bikes use 8 injectors for exactly this reason.  More modern engine management systems than my Megasquirt can cope with larger injectors, but that's the difference between a 150 ECU and a 1000 one.  That 850 buys the rest of my complete setup!  The Megasquirt will quite happily run 2 sets of staged injectors - only bringing the high power ones in as soon as the boost comes in, and leaving the standard Zetec ones to run at cruise.

I still need to get the plenum further modified in order to fit it under the SS1 bonnet, but it's not far away.  Currently I have Rover Turbo injectors fitted (max power - around 270bhp), but have sets of both larger and smaller ones.  I won't plumb in the small ones for the moment, but if I run into idling issues, then they're there - ready to go.

I'm still going to be using a chargecooler.  The Escort RS Turbo remains in situ for the moment, but I also have one from a Subaru Legacy on standby which is a bit neater and looks to be easier to fit.

Fitment issues

Whilst it mostly fits, there have been a few tweaks here and there; the inlet manifold still needs a tweak, and the engine mountings have been modified a little bit.  The o/s mount still wants to hit the oil filter housing despite being spaced out by about 10mm at the moment.  The n/s one had to have the alternator mounting removed to clear the water pump outlet; there looks to be enough space left under the inlet manifold to resite the alternator here instead, away from the turbo and manifold.

The front pulley is close to the front crossmember, but does clear it by about 5mm.

The turbo compressor outlet is currently VERY close to the chassis at the back - another 10mm of clearance would be nice.

I drilled the sump for an oil drain from the turbo, but got my sums slightly wrong and it prevents fitting of a starter motor - slight issue!  Another job I need to re-do.

The coil pack and thermostat housing are a tight fit at the back of the cylinder head, but it looks like it was meant to be there.

Updates so far..

I've now modified the exhaust manifold and turned the turbo around so the exhaust is at the back and inlet at the front - make the air piping much easier, but the exhaust will be a tight fit.  The engine mounts are now Landrover Diesel items which has allowed the sandwich take off plate to be fitted easily.

As for gearbox and clutch; to hurry things along, i've used a Fiesta RS1800 clutch on a 2.0 flywheel with the magic CCT133 release bearing fitted to the original type 9 gearbox.

The head has been rebuilt and is now fitted with a new water pump and cambelt.  The finishing line is in sight...


More Updates..long overdue!

Where do I start?

I've realised that the type 9 gearbox will last about 300 yards, so i'm currently going with an MT75 unit from a Scorpio.  I've chosen this one for a few reasons - the Sierra DOHC MT75 I had was stolen, but the Scorpio unit does offer a few advantages..


The Starter motor is now on the passenger side, so allowing easier routing of a larger exhaust


It comes with a hydraulic concentric release bearing, so i can fine tune the clutch operation for the Focus RS clutch I intend using

Sadly, there are also some disadvantages:


Add a hydraulic clutch (thanks to Stew Bramham for inspiration)


Add some means of electronic speedometer as the Scorpio unit doesn't use a conventional cable, just a speed sensor.


Fitting the thing in the hole!



To be honest, i've not done much on the car in far too long, aside from buying more bits!  I'm still considering alternator location and will try again to fit one in the original place, despite having cut the std mounting off!

My time has been taken up with No.1 of late, and the other turbo is still undergoing sill surgery to cure the early SS1 tinworm.


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