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Author C20XE Conversion. Parts and Fitting Guide
Premium Member


Registered: 5th Mar 03
Location: Taif, Saudi Arabia
User status: Offline
8th Jul 09 at 23:56   View Garage View User's Profile U2U Member Reply With Quote


Power steering bracket
Drive shafts (see below for more info)
Front engine mount
Modified gear linkage
16v Header tank
1.6 16v Fuel Pump & fuel clips
XE exhaust
Cavalier inner CV's
ARB Spacers (only needed if keeping ARB)
1.0 12v top hose for the right hand side of the rad (thermostat housing)
Rear gear box mount spacer
Transducer for gearbox ( to fit on mechanical speedo drive for electronic speedo)
Rear coolant gallery (standard xe from Calibra or Cavalier is fine)
Fuel pipes that attach to the fuel rail
Alt bracket
Alt adjuster
PAS pump
2 v belts
Twin v bottom pulley
Ecotec adapter plate and pipe or powercap (unless you want to cut bulkhead and use sfi box

2.0 Cavalier disks, calipers and pads
If you have coilovers/springs they need to be 300lb springs.


Engine choice

Any of the 20xe engines will do, unlike the nova there is no requirement to run the single vee alternator pulleys, the multirib stuff works perfectly well.

Obviously you need to first remove the original engine as per Haynes or other service manual.

Gearbox choice

Any of the big block gearboxes will suffice; they are all plenty strong enough for an xe engine. Choose based on cost, availability and ratios, but the normal f20 box from Cavaliers, Calibras etc is ideal


Before you fit the engine you need to remove the starting and charging loom from the original corsa engine and fit it to the xe. This makes the wiring really easy as now you have two completely separate discrete looms. Once the engine is in the car you simply plug the original corsa starting and charging loom back into the corsa car loom.

When you removed the corsa engine loom (with the engine) you should have been left with a square 9 pin plug in the drivers side foot well. The complete xe loom remains on the engine throughout and simply feed through the bulkhead in the same place as the original corsa loom. On the end of the xe loom you have 3 plugs which will need to be cut off, some of these will be joined to the 9-pin plug and some simply left. (You can cut the plug off the corsa loom before discarding it and use this on the end of the xe loom so that you can still easily unplug it for removal. (Easier to do this before you fit it to the car)

Wiring colours are as follows:

XE loom

Green - rev counter feed, wire to green on corsa plug (some corsas may not have this wire, in which case use a bullet connector and run a green wire to the rear of the clocks if you wish to fit a set with a revcounter.

Brown/Blue - ECU light, match to corsa plug

Brown/White - Diagnostics, match to corsa plug

Brown/Yellow - Diagnostics, match to corsa plug

Blue/red (thick) - Fuel pump feed, match to corsa plug

Blue - Coolant temp sensor feed for dash clocks, match to plug

Red/White - Autobox, unused in conversion

Red/Blue (thin) - electronic speedo feed, match to corsa plug

Red (large) - Battery +ve

Black (thin) - Ignition live - move this inside and match it to the corsa plug

Black/green - Aircon (unused in conversion)

Fuel relay block remains as is.

Engine mounts

Mounts are commonly available on ebay, or from Chris Astley (Link to Chris Astley Motorsport) The simplest is fitting to a 1.2 8v corsa where you just need the drop mount. This bolts between the engine block and the original rubber on the wing.

For 16v corsa models you will also need a wing mount which takes a calibra rubber. This bolts into 4 pre-tapped holes on the corsa inner wing (16v models don't have a rubber here like the 8v ones.)

The front gearbox mount is easy; just use the original corsa one.

The rear gearbox mount sometimes needs a spacer, sometimes doesn't. Undo the bolts and fitted the under car rubber as close to the box as possible, then fit the engine and measure the gap. Spacers can be made from flat bar or bought in if you aren't the 'home engineer'.

Engine mounts can be stiffened by filling the gaps with polyeurathane sealant

Gear linkage

The gear linkage needs to be extended by the same amount as your gearbox spacer if you have one. Insert new metal into the curved section being sure to keep the alignment. Also extend the top bar using a piece of threaded rod and some small rose joints.

The gearbox end of the linkage is not suitable on the Corsa, you can remove it and fit a nova end, then simply invert the white plastic block.

Coolant hoses

Use your original 1.2 8v radiator. You will need to fit the 1.0 12v top hose for the right hand side of the rad (thermostat housing)

The bottom hose and header tank hose are retained from the corsa.

The long hose from the cylinder head (under the dizzy) runs to the heater matrix.You may need to shorten this (use some copper plumbing pipe joiners with the solder removed as these have a ridge to stop the pipe blowing off. Simply cut it on the long straight run and shortened it.)

This leaves you with two outlets on the coolant gallery, one goes to the heater matrix and one to the header tank. The heater matrix pipe comes from the corsa, but the header tank pipe had to be made up from copper pipe and the bends from the discarded pipes.

Take this opportunity to dispose of the rusty spring clips and fit new stainless jubilee clips in their place.

Fuel supply

If you have a single point injected corsa your current fuel pump will not supply sufficient pressure for the new engine. A pump from a multipoint corsa must therefore be used, and transferred into the SPI carrier in the top of the tank.

In the engine bay, you should have the original rubber pipes coming off the fuel rail from the donor car. Sleeve these over the plastic pipes in the corsa and secure them. Use two proper fuel clips here, DO NOT use jubilee clips as they will leak.


It is best to use the standard air box in the conversion. Cone filters aren't always a good idea, especially in a cramped engine bay. Space is tight, with the clips on the air box just touching the cam cover on the engine.

The easiest way is to use an Ecotec 2.0 induction pipe and a converter plate for the TB (again available from ebay/Astley) Powercaps can also be used. The SFI box WILL NOT fit. Bulkhead modification is again a suck it and see job, but the powercap will almost certainly need it.

The ecotec bend is joined to the xe afm and then use the xe hose to the airbox as it contains the air temp sensor.


The standard xe manifold is the most suitable really, anything 4-1 wont leave sufficient ground clearance under the collector.

You will need to lower the ARB a bit if you wish to keep it (An upgrade is a 23mm one off a diesel combo van)

There will be some welding involved with the exhaust here!

Driveshafts and Hubs

Few options here:

22 spline smallblock shafts:

You can run a set of these from a TD or gsi corsa with the original outer hubs, bearings and small cv joints, using an mk2 cavalier 1.6 big block inner cv joint to mate it to the box, simple, quick, but obviously leaves you with vulnerable outer cv's

Big block shafts with machined hubs:

Machined hubs are available widely to fit into the std corsa bearings in the steering knuckle. You then use the big block driveshafts complete with outer cvs. This is ok, but there have been instances where these hubs have failed due to being too thin around the ends of the splines. Many people run these with success however.

Big block shafts with machined knuckles:

This is the best solution and involves machining out the steering knuckle to accept a larger bearing allowing you to retain the std hub dimensions. The knuckle should be carefully bored to 68mm by a machine shop and the circlip grooves deepened. There is also a small ridge on the hubs which should be removed to prevent them fouling the new bearings. Golf mk2 1988 synchro 4x4 rear wheel bearings can now be fitted.

It is worth checking the length of the shafts once the car is on the ground with full weight on wheels. If the shafts are too long they will bottom out and WILL NEED SHORTENING.

The equal length shaft setup from the calibra will also fit complete and is one of the best modifications on a powerful corsa.

Speedo feed

All the f20 boxes are mechanical drive, so you will need the mechanical fitting with the small gearwheel on it in the box from the donor car.

If your corsa has a cable speedo, simply attach the cable to the fitting on the box, however if it is electric things are a little more involved. All electric drive corsa boxes use an f28 style electric pickup, which cant be used with the f20 box. If you have this issue, use an early c14se corsa sender, which simply screw to the fitting on the box and requires an earth, ign live and the feed to the dash.

Suspension and brakes

Obviously these will need to be upgraded suitably to match the higher top speed and extra engine weight. (See Link to big brake Tutorial


On a side note, it is obvious that some aspects of servicing are best undertaken in a preventative manner with the engine out of the car. Change the timing belt and rollers, spark plugs, clutch, etc before fitting and the oil and water afterwards.


Once the engine conversion is complete you will need to let the DVLA know about it. This can be done on your V5C and sent back to them. You will need to declare the new engines cubic capacity and the new engine number.

You will also need to declare the engine change to your insurance company. Corsa Sport Premium members get up to 15% discount from:
Adrian Flux & HIC (Herts Insurance Consultants)

Emission testing is something that confuses a lot of people, and some testers too!

The law states that emission levels are tested to the age of the block. You therefore need to provide proof of the age of the block to the tester. If you cannot prove the age he is bound by law to test it to current levels. It is best therefore to keep a copy of the donor car's V5C to prove the engine age.

[Edited on 09-07-2009 by Ste W]

[Edited on 09-07-2009 by Ste W]

[Edited on 22-07-2009 by Ste W]

I would rather lose by a mile because i built my own car, than win by an inch because someone else built it for me.

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