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ford fiesta engine conversions
Contents:
CVH Engine Info
The CVH engine has powered a number of Ford cars since late 1981/early 1982. However, the basic design of the carburetted engine was revised in 1986 to take into account changing emissions laws, and the wider introduction of Unleaded petrol meant the fitting hardened valve seats across the Ford engine range.
On the carburetted engines, the ignition system was revised from a bulky separately mounted electronic ignition advance module (looks a bit like an amp) to a module built into the distributor cap. When buying your donor engine, it is best to pick up the distributor, coil and any ignition module from the same car. The piston and head design was also modified and became known as the Lean Burn engine, which effectively moved the combustion chamber from the head into the piston bowl. The lean burn engine produces less power and torque (about 4%) compared to the hemi engine fitted to the ERST, FRST and XR models.
One way to identify the lean-burn engines is by looking at the front and back of the head, i.e. exhaust manifold and inlet manifold sides. Hemi (ERST, FRST, XR) engines have a "hatched" or "waffle pattern". Post-'86 lean-burn engines have a smooth casting.
The CVH was on overhead cam design, compared to the block-mounted cam on the HCS engines, and had the distributor (later models used a coilpack) fitted to the flywheel end of the head.
The Mk3 Fiesta range used the following petrol engines:
- 1.0 & 1.1 HCS - carburetted up to 91 (J). Injected (CFi) from 91. Includes Bonus, 1.1L and LX.
- 1.3 - HCS - externally similar to the 1.1. Includes SX to 91. Identifiable from the 1.1 by large oval airbox.
- 1.4 - CVH - carburetted to 91, although some models were injected (CFi). All CFi from 91. Mainly Ghia models.
- 1.6 - CVH - carburetted was 1.6S to 91. Injected was XR2i and FRST, from 89 and 90 respectively, until 91.
- 1.4 - PTE - externally almost identical to CVH. Black rocker cover. Engine found in 5 and 3 door Si's and some Ghia models.
- 1.6 - Zetec 16v - found in some late Ghia models and most Si models.
- 1.8 - Zetec 16v - XR2i and RS1800 from 91 to 94
Conversions
[from HCS to CVH carburetted]
To go from an HCS carb engine to a CVH carb engine e.g. XR2, you will need the following as a minimum:
[engine, ignition and fuel system]
- 1600cc CVH engine with gearbox, flywheel, clutch, and all ancillaries including alternator and drive belt, water pump, timing belt, but excluding starter motor as you can usually use the existing starter.
- Exhaust manifold, downpipe and full system from any Mk3 CVH or PTE engined Fiesta. See the note on exhausts (next paragraph)
- Ignition system from the engine, including distributor, leads, coil, and any separately mounted electronic module.
- All vacuum hoses and airbox including mounting brackets, screws, etc.
- Inlet manifold, carburettor, mechanical fuel pump (mounted on top right of head - looks like a mushroom with fuel lines)
- Fiesta 89-91 1.6S throttle cable
- Top right hand CVH engine mount for a Mk3 Fiesta
[exhausts]
- Cats: Although you can fit an entire exhaust from a car with a cat, they are generally more restrictive and you should avoid them if possible.
- Turbocharging: FRST exhausts are specific to the turbo cars - you will need some specialist welding carried out if you want to fit one to any other type of engine. The FRST exhaust is the largest bore exhaust fitted to the Mk3 fiesta from the factory and is a minimum requirement for a turbo'd car.
[cooling system]
- Mk3 Fiesta 89-96 CVH or PTE radiator
- Radiator top hose - Halfords and most motor factors can provide one to fit. Flexible ones with a steel spring moulded in last ages.
- Radiator bottom hose for a Mk3 CVH Fiesta - Mk2 bottom hose is too short and will be prone to leaking when engine is under load.
- Other hoses as necessary, including thermostat housing to heater matrix hose, hose from heater matrix to head to bottom-hose
- Retain the Mk3 Fiesta header tank and supply hose
[suspension, steering and braking system]
Although you don't need to change any of these items, the following kit is really the minimum you will need for a safe install:
- Mk3 89-96 Vented brake calipers from any model with vented brakes if you do not already have vented discs (Note that all Mk3s use the same diameter front discs).
- Pads and discs to match. Avoid second hand kit. You can get a pair of standard Brembo discs for around £20 and Ferodo pads for £15 from a good motor factor's. Fitting will require a brake bleeding kit and brake fluid. Fiestas generally use DOT 4 fluid or above and 2L should be enough to refill the whole system.
- XR2i/FRST spec gas shocks are also recommended, as they are better equipped to handle the weight difference bwteen the HCS and CVH engines. New kit from a motor factor's is surprisingly low cost, eg KYB, and make a noticeable improvement in handling, as do new lower arms.
[to convert to EFi (e.g. XR2i 8v engine)]
You will need...
- XR2i engine parts, including EFi inlet manifold, airbox assembly, and air pipework.
- ECU, bulkhead-mounted E-DIS module, MAP sensor, ISCV, and CO adjuster modules.
- Engine loom to match engine (all are the same on XR2i engines, but FRST looms are made to match the ECU code - OFAB or OFAC)
- EFi fuel tank and fuel pump (other injection pumps may work but several different part numbers and specifications exist. If in doubt, only use a pump with EFi on the top of the sender unit).
- Inertia cut-off switch, and fuel pump relay.
- Plastic high pressure fuel lines from pump to fuel line, fuel line to fuel filter, and fuel filter to fuel rail. Your existing metal fuel lines can be retained.
- Fuel filter and mounting bracket.
- You may find the fuel pump loom multiplug already under your back seat at the fuel sender gauge if your car is a late 91 model. Otherwise, see the note on fuel pump wiring, below.
[to convert to Turbo]
- Note that the rad, fan and intercooler are turbo-specific, but the FRST radiator is smaller than the XR2i version despite the engine running hotter. If possible, you should consider running the XR2i radiator with an intercooler mounted in front of the radiator.
- You will need to fit the cooling fan in front of the radiator as the turbo fouls the rear-mounted fan position. The FRST type is thinner than the n/a ones but aftermarket fans from companies such as Kenlowe produce extremely slimline fans for mounting in cramped engine bays.
- You will also need the turbo-specific loom, ECU to match the loom (OFAB or OFAC), AMAL valve, and all the turbo air pipes.
- Additionally, the MAP sensor is also loom-specific - it is best to get all these parts from the same car.
- The E-DIS and CO adjusters, as well as throttle position sensor, idle speed control valve, and coolant temp sensor are all the same as XR2i 8v versions.
- The inlet manifold is the same as the 2i 8v version, although the gasket mating faces have higher torque settings than the normally aspirated inlets. Note that inlets with the remote ISCV require the fitting plate to attach them to the bulkhead. (afaik airbox mounted ISCVs were not used on the FRST but may be compatible - if in doubt, get the later type).
- Many thanks to Mark Stewart who pointed out that the Inlet Air Temp sensor on the FRST is of a higher spec and must be fitted.
- There are no differences between the XR2i and FRST fuel system (fuel lines, or regulator) except the pump and injectors - you need to fit the FRST items.
- You will need to fit most of the FRST coolant hoses, including bottom hose, top hose, if you use the FRST rad.
[fuel pump wiring note]
Pre-91 carb'd cars probably won't have the right loom connections for the fuel pump and EFi loom - you will need to patch these in yourself. Alternatively, you could locate the entire car loom from an injected model - any one from 89-94 (i.e. any non-airbag model) can be fitted, and a lot of these looms come complete with electric windows and central locking wiring.
[from HCS or CVH to Zetec]
The 16v Zeta/Zetec engine has powered Ford models from 1992 onwards. It was always fitted with a catalytic converter, and the engine management system was known as SEFi (Sequential Electronic Fuel Injection). The injectors used are of the side-fed type and the management was heavily reworked to improve hot starting (by allowing flushing of cold fuel around the injectors), and driveability. The engines can rev far higher than their CVH predecessors and produce peak power at higher revs.
Fitted in Fiesta and Escort models, the series 1 and 2 engines mount into the same positions and are most compatible with the Mk3 Fiesta shell.
The Mondeo versions of these engines use an incompatible sump, water pump, flywheel and inlet manifold design, as well as using a different oil pump which necessitates the use of the CVH filter. You should get these parts from the Fiesta/Escort engines.
Fitting is reasonably straight forward, although you should note the following points:
- The rear engine mount's top (vertical stud/bolt) hole may need to be redrilled approx 3/4" closer to the bulkhead.
- The front engine mount should be fitted whenever possible, but this involves drilling and welding on the front chassis leg. Running without the mount has been proven to work but places a lot of stress on the remaining engine mount and gearbox mounts. You should check periodically for excessive wear or tearing of the rubber mount.
- One problem with these engines are the gearbox ratios they were matched to – typically 1st and 2nd is longer and 4th and 5th are approximately 15% shorter than their XR2i 8v counterparts, with the FRST and ERST S2 ratios are slightly longer again due to a change in the final drive ratio. Please see the gearbox ratios page for more information.
[from HCS or CVH to Zetec]
[engine, ignition and fuel system]
- Zeta/Zetec engine with flywheel, clutch, and all ancillaries including alternator and drive belt, water pump, timing belt, and if possible the starter as Zetecs use a higher-powered item than the HCS and CVH engines.
- Exhaust manifold, downpipe and full system from any Zetec engined Fiesta.
- Engine management - loom, ECU, dash clocks (if possible), lambda probe, E-DIS (92-94 models only – from 94 the E-DIS was fitted in the ECU and ECU code will be something like A94AA 11A111 AA).
- All vacuum hoses and airbox (or a K&N/Pipercross, etc air filter) including mounting brackets, screws, etc.
- Inlet manifold. Wherever possible, use the 1800 manifold as the 1600 is slightly more restrictive.
- Fiesta 92-96 Zetec throttle cable
- Top right hand Zetec engine mount
- Front Zetec engine mount and hardware wherever possible.
[cooling system]
- Mk3 Fiesta 92-96 Zetec radiator and fan switch
- Radiator top hose - Halfords and most motor factors can provide one to fit. Flexible ones with a steel spring moulded in last ages.
- Radiator bottom hose for a Zetec Fiesta
- Retain your existing header tank.
[suspension, steering and braking system]
See CVH notes above
[from 1600 (90ps) Zetec to 1800 or 2.0L (130ps)]
This conversion assumes you have a 1994 Zetec with E-DIS internal in the ECU.
[engine, ignition and fuel system]
Items marked with a * are only needed if you are fitting a Mondeo engine and should be taken from your old 1600 engine
- internal E-DIS 130PS ECU (see ECUs note below)
- Block
- Head (with cams, etc)
- Water pump*
- Oil pump* (or fit a CVH oil filter to the existing oil pump)
- Sump*
- 130ps Fiesta/Escort throttle body
- 1800/2.0L MAF
- 1800/2.0L lamda sensor
- 130ps exhaust manifold (finis 6691585 eng code 928F 9431 JB)
- 1800 downpipe and cat
- 1800 inlet manifold (you can fit the 1600 one but it is slightly restrictive)
- 1800/2.0L injectors (essential!)
- Flywheel* and matched (manual transmission) CPS*
Fitting a new clutch and gaskets (headgasket, rocker and sump) is always good practise. Always use the Ford recommended sealant on the sump gasket)
You should also fit a longer ratio gearbox. The 1600CVH XR2i 8v and FRST boxes have good ratios but the RS1800 boxes will suit, although 4th and 5th are about 15% shorter than the CVH's ratios. Note that the 1800 Zetec Fiesta Mk3 and Courier Diesel boxes from 1990 onwards are the only boxes which were fitted with stronger internals than the standard kit - no BC box before 1990 had any kind of strengthened internals. For more information please see the transmission guide.
[about 130ps ECUs]
While you *can* use a 90PS, 105PS or 115PS ECU, most will under-fuel at the top end of the rev range. For the best performance (and to avoid pinking), you should find a 130PS ECU.
For internal E-DIS (e.g. post-94 Fiestas), you need an ECU with the following 4-letter ID code on it:
These are the ones we have so far found to work - there may be more. If you find one, please let us know! The engineering codes for these ECUs are listed on Microcat as 94FB 12A650 CC (Fiesta '94 RS1800) or R93BB 12A650 GD (Mondeo 2.0L)
Nb: our 1992 RS1800 (external E-DIS) ECU code was GTE.
The ECU's engineering code should contain either 93 (for Mondeo ECUs) or 94 (for Fiesta ECUs), e.g. 93AA AAAAA AA
Warning! you *will* fry the ECU if you put an ECU designed for external E-DIS on a loom from an internal E-DIS car, and vice-versa. ECUs with external E-DIS generally have a 92 year engineering code. If in doubt, consult a scrappie or take the engineering number to Ford for checking.
That's yer lot!
| Disclaimer: Please note that you should not even think about doing these conversions unless you can afford to have the car off the road for a while. Information contained in this article is provided for information purposes only - if you're too damned daft to change your engine, fine, just don't come crying to me if you fry it. |
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Please mail me if you spot an error, omission, or something just plain dodgy. Also take a look at the disclaimer at the bottom of the page :o)
Although I've tried to make this page reasonably comprehensive, it is likely to have a few errors and cock-ups. If you have any queries about this conversion, good advice from the peeps who have done this before can be had by posting a question on the Fiesta Turbo forums. More information on engine conversions can also be found at Mark Stewart's Fiesta Projects site. |
[FAQs]
A couple of FAQs from fiestaturbo.com forums users:
"What parts of the running gear must I change?"
The answer is, nothing! You *should* change the brakes to the vented type fitted to all ABS-equipped, diesel, CVH and Zetec engined Mk3s/Mk3.5s. Lower arms, rack, driveshafts (as long as the CV joints don't knock or rattle excessively) will be fine. Note that a change of brake rotors, pads and fluid are always a good idea and cost compartively little from a Motor Factor's. You should fit standard-spec gas shocks for the XR2i 8v and CVH/Zetec weight springs.
"Will my speedo gearing be wrong with a different engine/gearbox?"
No - the BC, iB5 and MTX75 boxes all seem to use the same speedo drive gearing. You can retain your existing speedometer (but see the next q regarding the rev counter).
"My rev counter reads double the revs it should - why?"
Usually this happens when you fit a coil-ignition system to a car that was previously fitted with the E-DIS wasted-spark ignition system with coil pack. The only easy solution is to track down the rev-counter module from a 1400 CVH Ghia or 1600S Fiesta (89-91 models).
"I hate wiring - how hard will this all be?"
Generally, the Mk3 Fiestas used a separate engine-bay loom from the car-side loom and the looms connect at the centre of the bulkhead panel at the back of the engine bay. Two styles of connector were fitted - carburetted models from 89-91 had a 6-pin connector providing ignition-switched live feeds, oil pressure, and a couple of other bits and bobs. Injected models (i.e. all other models 89-96) had an 8 pin connector. If you are fitting an XR2 engine to a carb model, some lateral thinking is best - your best bet seem to be to take the dizzy and wiring from a 1600S Mk3. Fitting an injection engine to a pre-91 carb Fiesta requires the fitting of the fuel pump control circuitry; ideally swapping the entire car loom is the easiest way to do this if you don't want to build up the loom yourself, but adding in the bits you need is not too hard and can usually be completed within a morning with the right bits of wiring, which can be stripped out of a donor loom without too much fuss.
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