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T25 Subaru engine swap – Part 3

Well, we’re almost there! Last time around we left you withthe engine bolted into place for the last time and about aday’s work ahead of you to finish up before hitting thehighway. But be patient – while the end may be in sight,don’t try to rush these vital last steps, in particular the

modifications to the heating and cooling system.

Final fitYou need to start by installing the RJES-modified reversed coolant outletmanifold. This allows the engine’s top hose to point towards the radiatorpipes in the front right-hand corner of the engine bay. In the Subaruengine bay, the radiator was located in front of the engine – but in a VWinstallation, where the engine is reversed, it is effectively located behindthe engine (in fact, all the way down at the front of the T25).

Take a good look at the condition of the cam-belt – it’s somethingthat is easily replaced with the engine out of the vehicle, but if you didn’treplace it before installation, have a second look to make sure of itscondition. If in doubt, replace it now.

Refit the induction manifold, complete with throttle body and associatedlinkages. Don’t worry about the throttle cable, though, as you’ll bereplacing that in a moment.

Next up is the heater bypass adaptor. This is a vital component on aSubaru conversion. Without one, your engine will overheat as soon asyou turn off the heater, as you’ll be cutting off the flow of water. TheRJES-supplied adaptor is a simple bridging piece that allows a certainamount of water to flow through the heating system at all times.

You can now install the original header tank in a new location in thefront right-hand corner of the engine bay using the RJES bracket. Thisrequires the drilling of two holes for self-tapping screws, but apart fromthat it is straightforward.

Connect up all the coolant hoses, following the RJES coolant circuitdiagram which is available as a PDF file on the CD of fitting instructionssupplied with the conversion kit. One of the nice things about the RJESconversion is that there are no cheap convoluted hoses used, whichadds to the ‘factory-fitted’ look. Be aware that there are some very badlydesigned coolant circuits available on the Internet, which will be verydifficult to bleed air out of, so follow the instructions carefully.

The original fuel pump is no longer used, so you need to fit a newhigh-pressure one, along with a filter, to the inner side of the right-handchassis rail. Rubber mount the pump, otherwise it will be noisy. In fact,the sound of the pump running when you first turn on the ignition is oneof the giveaways that all is not stock! You should replace the whole VWfuel pipe with new 8mm-bore fuel-injection hose to SAE 100 R6, and adda return hose to the tank. Fortunately, even T25s with carburettorsalready have a fuel return fitting in the tank.

Connect up all engine wiring, following the instructions – it may lookcomplex but the modified loom is easy to install and should present noproblems – even to someone terrified of electrics! A new gearbox earthstrap is highly recommended, too.

Next you can fit the RJES throttle cable – a direct replacement for theoriginal – followed by the induction system. The plastic inlet pipe from a1990–1994 Subaru Legacy fits between the throttle body and air-flowmeter, while an aftermarket cone filter and adaptor is the simplest filterinstallation in the available space. Finally, connect the breather pipes tothe induction pipe.

Incidentally, it’s worth mentioning in passing that the Subaru

1. There’s not much to give the game away. To the casual observer it

still looks like a stock Type 25 but, as the local Saxo boys have

discovered, it’s a rocketship away from the lights!

3. Everything is so easily accessible – and it’s hard to think that the

Subaru engine is an afterthought, so to speak. All that remains to be

fitted here is the inlet ducting, and then it’s time to tidy up the wiring

and hoses prior to that first test drive

2. Reversed water manifold is necessary to allow the Subaru engine

to function with the original VW cooling system. A detailed PDF file of

the cooling set-up is included in the instructions from RJES

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In this, the final part of our series on installing a Subaru Legacy engine in aType 25, we take a look at the cooling system and our first trip out on theroad. Be prepared for a life-changing experience…

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