Engine swap - March 2010

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After spending several weeks trying to sort out the 1600 Zetec SE engine, it transpires that it's a dud so I've resigned it to the back of the garage and I went out and bought another engine. This time I've gone for the 1.7VCT from a Puma which should give 125BHP in standard trim. I've elected to use the standard Ford EEC-V ECU to control it as the Megasquirt doesn't support the variable cam timing. Also, the Ford ECU is a lot simpler to connect since it is almsot a drop in replacemnt for the wiring I've already got.

The first job is to get the engine up and running without making any changes just to be sure that this one is ok before I start chopping everything about. So, the engine was propped on a pallet, and the wiring loom laid out. An old coffee jar was pressed into service as the fuel tank and I acquired another fuel pump for this test. The immobiliser was wired in and a spare ignition key was quickly connected. The coolant hoses were just connected without a radiator because I was only going to be running the engine for a short while, but I did do an oil and filter change just to be on the safe side.

And here is what happened...!


So not at all bad even if the PAS pump did spew it's contents everywhere and the revs were a bit erratic!

The next step is to start stripping down the Mojo to do the actual changeover. Here's how it started, and how it looked 20 minutes later.

One of the big problems that is going to arise is that the inlet manifold on the 1.7 is much larger than the 1.25, and that barely fitted. So I'm expecting to do a fair amount of chopping around to make it fit. I started off by taking some rough measurements and I think that I need to drop the engine by about 20-30mm, and move it back by about 15mm and this should give enough room. Initial thoughts were that I could probably do this with some offset spacer blocks on the engine mounting points but a closer inspection rendered this path pointless. As expected, the 1.7 has a different bolt pattern and location for the OS mounting point due to the variable camshaft timinig mechanism. The engine mount on the gearbox looks identical so this may only need a spacer plate.

The left image is the 1.7 engine mount and you can clearly see the extra bulge under the black cover where the VCT mechanism is. The mounting bracket is slightly larger to accomodate this which means that it's not a simple job of redrilling holes - a new mounting bar will be required. I called Jeremy today to make sure I wasn't missing anything obvious, and it transpires that he has a part made engine mount in his spares box so I'm hoping to get some photos of this soon to see what can be done. Some other references have been found at Richard Burgess' build diary here. He's built a Riot with the 1.7 engine and the Mojo and Riot have fairly similar engine bay layouts so this gives me even more inspiration for what needs to be done.

In the meantime, I'll crack on with the disassembly!


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