Galaxy and Scorpio 2.3 bottom end conversion

Guide by EXUPTURBO, Revised by Icurus


A tuning option that is becoming more popular these days is the use of the Ford Galaxies 2.3 litre bottom end. 

There are several ways to do 2.3 conversions, either with the Galaxy or RS head, with RS sump or Galaxy sump and balancer shafts.

If you use the Galaxy head you will have to get the water way welded up that is used on the Galaxy for the thermostat housing and get the black plastic heat insulator that goes between the head and the inlet machined for individual O rings or use gasket paper.


You can not use the original RS inlet set up on the Galaxy head because there are cut outs on the face of the Galaxy head which would not allow a seal if you used the single RS2000 O ring.

If you use RS2000 head then no modifications are required, it will bolt straight on and you will be able to use the RS inlet system, but you will end up with a compression ratio of 11.8:1 which will kill your pistons through detonation if you do not constantly use 97RON fuel or higher, such as Optimax etc, though you will gain more power as a result of the higher compression.


The only way out of this is to have the pistons machined down by about 1.2 mm, this can only realistically be done with the pistons removed from the con rods, (the gudgeon pins are an interference fit in the rods, and pressing the pistons from the rods tends to destroy them!), even if you get the pistons machined whilst on the rods you can never get it balanced properly. This is the bit where it can cost a LOT more money than going the Galaxy head route if you do not want to be tied to 97+RON fuel use, as 2.3 Galaxy pistons are around £160 each.

Once you have decided which head to use you will need to get hold of the following from a scrap RS2000 engine.

Camshafts (the Galaxy cams produce less power)
Oil sump
Oil pickup pipe
Mains bearing cap bolts
Sump baffle
Dipstick tube
Flywheel (you can use your old one)
Lower timing chain cover
The semi circular casting that bolts just in front of the no 1 mains bearing that fits the RS sump and also contains the oil pump chain tensioner (Very possibly its the same part on the Sierra DOHC 8V engine) as this is not available without a cylinder block from Ford.


You will require these new parts:

RS timing chain

RS oil pump chain

Chain guides, upper and lower, for both chains

2.3 head gasket and the other gaskets needed to assemble the engine

Con rod bolts if these have been removed

Head bolts

Now find a friendly machine shop that can machine the block and make up a small blanking piece to fill the mismatch between RS sump and Galaxy block.

While the engine is there you will need to get the oil feed that used to go to the Galaxy balancer shafts blocked, by tapping out and fitting a blanking plug, an M8 tap should suffice.


Now it's just a matter of bolting it all together and fitting it, the engine will bolt straight in and use all the RS power steering stuff/alternator etc.


1. If you replace cam chain and timing sprockets only use the Galaxy crank sprocket as they are different and will cause problems with the front pulley.

2. The bolt holes for the inlet system on the Galaxy head are not as deep as on the RS head, so the bolts may bottom out before the correct clamping force has been reached, which may cause an air leak.  To solve this you can either cut down the bolts, get some new shorter ones or, pad out the bolts with a washer.


Inlet manifold face of 2 litre head



Inlet manifold face of 2.3 head showing the water way that needs to be blocked up


2.3 head with water way welded

bits needed from 2 litre i.e. half moon casting, baffle, main studs and oil pickup


If you use the RS sump on the 2.3 block then this hole needs blocking off to prevent loss of oil pressure.  This used to feed the balancer shafts.


The 2 litre block showing extra metal


2.3 block showing difference


RS sump on 2.3 block showing mismatch and hole

Block machined and insert in place to fill the hole


Pic of the nasty power sapping balancer shafts that spin at twice engine speed, sapping BHP



The Scorpio block 


The Scorpio block has a few differences to the Galaxy block.


The dipstick hole is towards the rear of the block and if this location was used then a false oil level would be the result when using the rs tube and dipstick, so you need to have the block drilled in the fwd dipsticks location, fortunately the block does have a lug moulded for this which helps in identifying its location.


The crankcase breather PCV valve is also located in a different location, but as long as you use the Scorpioís associated pipe, it will connect to the rs inlet manifold with no probs.


The water pipe outlet behind the water pump needs to be moved 90 degrees as itís also in the wrong location.  There is a blanking plug in its required location, and this can be un-screwed and swapped for the water pipes elbow.  This picture shows the plug moved to its correct position for use in the Escort.



Also, I noted that the Scorpio blockís CPS has a wider top section, so you need to retain the Scorpio one as the rs one will not seal or even fit snugly in the hole.


The 2.3 crank on the Scorpio is the same overall length as the 2.0 crank but has a slightly different timing chain sprocket.  In this picture the 2.3 sprocket is on the left.




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