Pondering an engine swap - stupid question amnesty thread

I seem to recall the K4M is in Clio and Megane of the era?
Not a bad little engine, although possibly as much of a squeeze in a Twingo as the 172/182 engine is.

How about trying to get hold of the 1.7 injection lump from a Renault 5?

I'm afraid I don't have any Renault specific advice or experience, but I had done an engine swap, and helped friends with theirs also, so have some general thoughts that might be helpful.

In general I'd say it's perfectly possible with some normal tools by someone who's mechanically competent and has the right attitude. I will add to that, that a welder and some basic fabrication skills makes things so much easier. You will also need an engine crane.

In my head there's several stages to an engine swap. Firstly there's the 'Will it fit?' question. To an extent any engine will fit in any car, but most of us don't want to be chopping the body shell up to make the engine fit really. Skipping through that video, it looks like the engine fits in that space ok.

Next you've got to mount the engine in place. If you're lucky and doing a same brand engine swap then there's a chance you can mix and match engine mounts from different models and it will bolt in. I know, for example, there's various VAG group stuff where you can do this. But for most engine swaps that will mean fabricating some engine mounts and that means having the right welding/fabricating skills, or being able to call in some favours.

When I did my 13b rotary engine swap into my Mx5 about 10 years ago, I couldn't weld, but was able to get one of my Dad's colleagues who was a professional fabricator to do it for me. He did a great job, but I will say the process of having to do all the measuring and drawing out, then deliver the engineless car to him to have the mounts welded up, then get the car back and fit the engine, then take parts back to be modified, and so on, was slow and frustrating. If I had been able to weld and could have done it on my driveway with the ability to drop the engine into place and lift it back out to check it's all lining up as I go, it would have been much easier.

Scanning that video, it looks to me like they've welded up some new engine mounts, so probably not a bolt in type swap. So really you either need a mate who's gonna be happy to spend some days helping you, or you're going to have (or learn) those welding skills.

Now in YouTube/SEMA world, thats the engine swap done. In the real world, you've only just begun. But it's not necessarily that difficult. You now just need to work through each of the engines systems, working out how you're going to join the new engine to the car. So driveshafts, gear shifter, cooling system, fuel system, wiring, etc. Some of this may be simple, like the engine mounts you might find that you can use driveshafts from either the new engine, your original car or can find another model from the manufacturers range that has the combination of dimensions you require. Or you might find that you need to have custom ones made up, which can add cost and complexity to a swap.

How you do the wiring is up to you, you see various solutions from the long winded and expensive route of stripping the original loom back removing the wires you don't want, adding new wires you do want and hooking it all up to an aftermarket ECU for a factory like install, through to just tucking the old loom out of the way and putting an entire second loom and factory ECU that matches the new engine and having that zipped up under the dashboard. Either way you will need a plan to make it work, and if that included using the stock ECU from the new engine, it means knowing about any issues with immobilisers/check engine lights/etc.

It's all possible, lots of people on here have done successful engine swaps, and often the only way to learn is to jump in and go for it. You have to expect that it's going to take 3x longer than you estimate (and probably cost 3x as much) and that there will be challenges along the way. But if you're up for the challenge go for it

Also, if the bellhousing pattern matches and you can retain the Twingo gearbox, thats driveahafts, clutch and shifter mechanism ticked off the list to start with

Thanks for the heads up...

I've got my eye on an early Scenic with the 1.6 K4M as a donor.

Reading that they will be fitted with a JB3 gearbox, whereas the Twingo will have the JB1...some conflicting information on whether the JB3 and 1 bellhousings are the same although most of the internet suggests the only difference is in gear ratios.

By this logic I should be able to use the Scenic box but the Twingo driveshafts...wondering if I could pilfer the brakes off the Scenic too as they're bound to be better than that dinky solid discs on the Twingo.

This could well be one potential problem overcome... I'm off to join a Clio forum to confirm.