The Mini

A 1980 Mini LE made by British Leyland Morris. 998cc’s brand new, but had probably lost a few horses over its 25 year lifespan by the time it came into my ownership.

The first major upgrade to the Mini was to get it painted. Dark silver with white roof and matching bonnet stripes replaced the olive green that had given it the nickname ‘Kermit’.

12″ Minilite rims and a jet black interior rounded off this well kept classic.

Upgrades

Fairly early on I learned about Mini’s and their leaks, and thus began a fairly standard investigation and drip system setup consisting of an old piece of lino that would need wiping every journey.

Of course, this allowed me to gain some knowledge and understanding of the Mini, the A-series engine and the inner workings of cars, which previously was limited to 4 tyres, go pedals and steering wheel.

In an effort to improve the leak, I came across a 1275cc engine, and began the journey of taking out the 998 and putting in the 1275.
In terms of engine swaps, this was relatively easy. However, with more power, comes more responsibility in the form of brakes. I picked up a set of 4-pot disc brakes from a Metro, which are able to be straight swapped onto the Mini.

The 1275 came with twin carbs, which sounds awesome, and looks awesome, but are a nightmare to set up. Research suggested that a larger single carb would work just as well. But I was never able to get the right needle dialled in and the engine always ran dodgy, spluttering sometimes, but rich at others. In the end, there was additional leaks, and so the 1275 had to go.

My expertise in the automotive world is relatively limited. However, my brother is in the business, and so, embarking on this project with him has not only made navigating my inexperience easier, but it has been something we’ve worked on together and made an unbreakable bond together.

With his help, we decided to upgrade the engine to something more reliable. Turning it electric was going to be expensive and somewhat experimental at the time. Getting a small engine from a Micro, or Civic was a better route, given that others have done this and there’s a lot more information out there on how to do it.

Donor Car

There are several ways to go when it comes to Mini engine conversions. The most common, and probably the most sought-after, is with a Honda b16a VTEC engine. The VTEC delivers a fair amount of go-forward and the dimensions are relatively small. Small enough with the tiniest of margins to fit in the engine bay of a classic Mini.

The best way to do it is to get a car that has a VTEC in it. That way it comes with the mounts, the wiring, the ECU and all the additional parts you wouldn’t necessarily get if you just buy a b16a engine.

The donor car for this project was a 1992 Honda CRX Del Sol.

The VTec

There are two main issue with getting the VTEC into the Mini. The first is cutting the engine bay a bit to allow the VTEC to fit. The second is getting a subframe for the engine to mount onto.

In New Zealand, this isn’t always easy. We have stringent rules around certification and modifying vehicles. The subframes has to pass the checks and adjustments to the suspension have to go through a design approval process. Manufactured subframes, such as AllSpeed, have to have their welds checked prior to painting, and so importing these isn’t always an option.

Subframe

The best method for making a subframe is to use the towers from an original Mini front subframe, and then build a frame off it to hold the b16a. The Mini’s suspension and wheel geometry is all held within these towers anyway, and so it makes sense to keep that as is.

The subframe is based off KJB Fabrication’s frame, and Dutchey’s VTEC frame. Both of these have got extensive documentation on the web.

Building this from scratch was not at all easy. I’m very much used to working in 2-dimensions when drawing and designing. Drawing it in 3D was easy enough, but when it came to actually building it with 30mm steel box section, there was a lot of trial and error before the frame completed with angles and cuts and grinding all taking time and brainpower. For starters, I had never welded before, and so that in itself was a steep learning curve.

I mocked up the frame dimensions using timber, just so we could see if the design would fit. Using cardboard templates was invaluable, especially when working out angles of the frames as it comes off the original towers. Every joint of box section needed to be fishplates to meet code.

It was several iterations before we could safely say that it would fit in the Mini’s engine bay, as well as contain and hold the b16a engine. Following that, it was even more fettling to get the subframe AND engine into the Mini, and further work to get it loaded into the Mini and bolted on.

The certifier wasn’t too enamoured with my welding efforts and so we got a friend of a friend to tidy them up. This allowed the certifier to give the all clear with the subframe, with him double checking that the suspension geometry wouldn’t be affected by it. I assured him it would not.

With the all clear given, the frame was painted and the task of fitting all the additional parts that make the engine work began. Intake manifold, exhaust manifold, radiator, and alternator all required a fair bit of work to get them into position and operating correctly.

Intake Manifold

The Intake Manifold required a bit of work, but was well within my level of expertise. Cutting the tubes in half was the most nerve racking, as it signalled a moment of no turning back. At this stage, some fairly robust hose clamps and silicon elbows would make up the modification to fold the manifold forward so that it doesn’t fowl on the bulkhead of the Mini. Despite people warning against this due to their tendency to come apart, we figured that at this stage, it was our best option, at least as proof of concept and to get the b16a running. It’s certainly a lot easier to do this than to weld cast aluminium!

At a later stage I will investigate into a more permanent solution. The benefit with having the elbows working, is we now have something to reference off of when making the permanent manifold elbows. It will keep everything in the right position for the new elbows to be made from.

Body Mod

Along with getting the Intake Manifold modified is creating enough room to fit it inside the Mini. Because of its location and the tight fit the b16a already has, most of the extra engine parts actually have to be fitted after the engine and subframe are loaded into the bay and tower bolts tightened. The Intake Manifold requires the bulkhead of the Mini to be cut back, even with the elbow modifications. Of course, this takes time, with getting the engine into the Mini, figuring out where the cuts have to be made, taking the engine out again, making the cuts on the Mini, and then fitting it back in again, and checking that the manifold fits. This was made 100x easier with the use of a hoist and a trolley system for the engine, where it could be rolled away from the angle grinder sparks as the cuts of the bodywork were made.

Alternator

The next big mission was the alternator.

The original position of the alternator on a b16a engine is under the intake manifold, but is totally unsuitable in the Mini as at this location, the b16a itself is almost up against the firewall to the cabin.

There are several locations people have fit the alternator in the Mini. Some mount it spun 180 degrees and put under the passenger side fender. This isn’t ideal as the wheels are right there and the amount of dirt and water that it would get exposed to would be troublesome to say the least. The other location is level with the intake manifold. There are no mount points here, so a tall bracket has to be made to reach any mounting holes on the back of the engine block. Longer belts are needed, as well as a tensioning pulley and a fixed pulley to adjust the trajectory of the belt so that it clears the subframe. All of this was done while not only fitting the alternator into a spot, but mounting it off the engine from locations that were accessible, and ensuring that the whole system lined up so that the belt would run nicely.

Exhaust Manifold

Many people get custom exhaust headers made up for the b16a to fit in their Mini. Regardless of this, some modifications usually have to be made to the front lip in order for the exhaust to fit down into the tunnel. The grill fits over the front of the frame and so there is some clearance at the front for this, but not a lot. I definitely do not want to modify the grill as I want this to look as standard as possible when all is said and done.

The exhaust manifold that came with the engine from the donor car was going to be the best option at this point. For one, we already had the part, and custom headers were going to be expensive. For two, it was fairly close to fitting just fine anyway, and the cut that was required would just be able to be covered up by the grill. There is a slight concern around the heat it will cause, but we will deal with that in due course.

Just like cutting into the manifold, cutting the front lip to fit the exhaust manifold in was incredibly dicey. The nerves were very high, and I didn’t want to cut out more than what was needed. At the same time, I needed to cut enough away for the manifold to be put in position and fit in. And just like the Intake Manifold, the engine had to be put in and taken out each time so that the cuts could be made by the angle grinder without sending sparks all across the engine.

I am not ruling out getting custom headers made, but just like the Intake Manifold, at this stage, using the existing Exhaust Manifold is a way of testing and a proof of concept.

Radiator

There are lots of considerations for the radiator. Essentially, the Honda radiator that came from the donor car was not going to fit in the space we had available. It was close, but every angle was fouling somewhere on the subframe or the fenders, or the engine itself.

When changing radiators, especially the dimensions, the capacity of the existing radiator is the most important value. This is essentially how much coolant it can take care of in order for the engine not to over heat. You need to get something that had a similar capacity, but smaller dimensions. This is sometimes achieved through different thicknesses, or by slight adjustments of angles in the radiator body.

A performance Mini radiator has a capacity that is only slightly less (A soda bottle’s worth) than the Honda radiator. Using a standard Mini radiator as a size guide, I found that I could fit it in to a location, albeit at an angle. I put in an order for a performance Mini radiator and with a slight modification to the location of the bottom hose nozzle, fitted the radiator into two brackets that attached to the subframe.

New hoses had to be ordered in, and getting some adjustable ones of these is a must, as the standard ones that have pre-made shapes for the bends of the engine no longer work with the new location of the radiator. I got some that are meant to form to the shape they are in once they have hot coolant running through them.

Mounting Locations

The key to all of these parts is to think about where they’re mounting to. The alternator for example, can’t be mounted to the subframe, as if the engine moves under acceleration, then the belt can loosen or tighten or adjust the angle and cause considerable damage. The radiator on the other hand, can be mounted to the subframe, as the hoses that connect to the engine are flexible enough that they will adjust with the engine should it move. Taking the movement of the engine and what part you are mounting where is definitely something to take into consideration at all times.

Wiring

One of the main benefits to getting a donor car with the engine is that it comes with the wiring looms. Usually if you buy an engine on its own, you won’t get the wiring with it. This would lead to you having to build a wiring loom for it by hand from scratch.

Luckily I know a guy; my brother. I don’t know how many hours he took leaning over a 1992 Honda CRX Del Sol wiring diagram, but essentially he was able to cut out the redundant wires because the Mini didn’t need it, and re-route parts that were in different locations and fit it all into the Mini.

We used the Honda ECU as a start point, and then built a central point under the drivers seat where relays and fuses could all be housed. The reason for choosing the driver’s seat is because most people getting in and out of the car use the passenger side as the seat folds forward. Having the electronics over that side would be troublesome with people always stepping on it or tripping over it.

We used several plugs that allow for the loom to be disconnected at different breakpoints and essentially allows the engine to be removed without having to pull the whole loom out. It essentially makes an engine side and a cabin side of the loom.

Running

With the engine in, mounted, and bolted onto the towers, the intake manifold, alternator, exhaust (pipless at the moment) and radiator (filled) were all fitted and working and the wiring all done, we were ready to turn it over.
Using some engine starter spray in the manifold, we turned over the key. Several iterations of this process happened, with some small adjustments being made to throttle positions, and eventually it roared to life.

Then we decided that we should probably put some oil in the engine – a step overlooked in the excitement of trying to get it running!

Following this, it was time to get it running off its own steam. This meant it was time to hook up the fuel tank and run new fuel lines. The original Mini fuel pump was suitable for a carburettor setup, but was not going to be able to keep up with fuel injection. However, the later 1990’s Mini’s came with fuel injection and so had SPI fuel tanks and fuel pumps to suit. We got our hands on one and got it installed. The fuel lines needed to be replaced to allow for more fuel flow and so running hardline down the body was carried out by another friend of a friend.

We put some liquid gold in, ensured everything was hooked up and filled up, and turned over the engine. The fuel pump did its thing and after a few cranks, the engine spluttered to life. For a bit. It wasn’t humming properly. Turns out we hadn’t quite got the timing right. Sorting that out, the b16a purred to life and idled just fine.

Another stage complete!

Set Back

As with any projects of this nature there are going to be set-backs. However, this was one that I was not expecting.

I had just sent the axles of the Mini and the Honda off to get merged. Essentially the Inside part of the Honda axels that connect to the b16a driveshaft needed to be connected to the outside part of the Mini axel to fit into the Metro hubs. This is not a task I could do myself, as it needs to be done at a high level of accuracy and performance for it to pass the certification.

While waiting for these to return, a freak accident happened where a car plowed into the workshop, crashing into a van which crushed the Mini between it and the workshop benches. Significant damage was sustained to the front and back, with left fender folded up, bumpers damaged, boot caved in and boot floor crumpled in. Luckily, it happened after-hours so no one was working on the van or Mini at the time.

The fact that we were so close to the home stretch, to be set back this much was disheartening to say the least. The 5 month long battle with insurance was even more so. The icing on the cake was getting the merged driveshafts back a week after the accident and not being able to move forward with it all!

New MINI

With the original 1980 LE written off, and the damage coming with a substantial repair bill, it was going to be easier and cheaper to purchase another Mini and start again.

Luckily, nearby friends just so happened to have one available to purchase, and so after picking it up and getting it to the workshop, it was back to square one.

The first thing was to cut out the parts in the engine bay required for removal. By using the previous body and taking measurements from it, this was a lot easier and quicker since the last time we did it!

Then it was checking fitment for things like the ‘Frankenwiper’ that was the last part being worked on the previous car before the accident.

Loading in the new loom that we made up and passing the wires through the new body took a while, and then it was on to getting the rear subframe (which was in better condition) fitted and loaded.

New Subframe

While fitting the engine and subframe into the new body, we noticed that it was not fitting as expected. Whilst part of it was actually clearing tight spots easier than before, other parts we not.

It all pointed to the chance that the subframe was damaged in the crash and had been twisted and warped.

We booked in a weekend to fabricate a new one, with adjustments made from various problems we’d noticed on the previous subframe. Welding techniques have improved due to many YouTube videos being watched since last time. We lowered the side arms on both sides along with proper joint techniques, ensuring that we kept things aligned with each other, while taking measurements off the old subframe. Positioning the engine mounts became the most difficult part, although we will make one of them removable this time so loading the engine in and out isn’t as problematic.

Design Approval

Another big change we are going to be making is with our certifier. We are working with a new certifier and it has been recommended to get advice from the technical team at LVVTA through the Design Approval process.

While we have begin the initial fabrication of the subframe, we haven’t completed it to it’s final stage so that any changes we might need to make it can be performed without undoing a whole bunch of work.

The benefit to going through the Design Approval process is that if the design is approved, then it will make the rest of the certification process a lot easier, as the certifier will be able to use it to check off that we have met the design requirements they set when it is inspected. There is also a little bit of peace of mind knowing that people with more expertise and engineering knowledge have looked over it and made their professional opinions on it.

Dream; It’s Over

I know they say don’t give up on your dreams; but to carry on where we were heading, the Design Approval Team at LVVTA were requiring an engineers report to confirm that the modifications I was making to the original subframe towers weren’t weakening the structural integrity of them. Initial investigations into what that engineers report would cost, and it became apparent that this was the end of the road for this dream.
I called it quits on driving around in a VTec Mini.

Reborn

Within a few months of pulling the plug on the project, I had sold the b16a engine, and eventually the Mini shell and bits that I had set aside for the project.
At Christmas 2025, the next chapter of my Mini journey began.

I took possession of a 1994 Rover Mini on Christmas Eve, while up visiting family in Rotorua.
Several factors lined up that were signs that this was the one:

• I paid what the insurance had originally paid in the write-off of the original Mahvin.
• It is the same colour as what I had Mahvin painted.
• It came available as we were arranging our visit up north, and the owner was happy to hold it for me until Christmas.

Everything lined up.

Over the next few months, years, however long it takes, I’ll be upgrading the Mini and giving it a new lease of life. Various parts from the original Mini will be making its way onto the new Mini, and the spirit of Marvin carries on.
I will add any updates predominantly on Instagram, but I’ve also created a category on this website for any articles or updates involving Marvin the Mini.