1973 Hillman Imp 1.6 De Luxe...........wait, what??!

1973 Hillman Imp 1.6 De Luxe...........wait, what??!

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Kitchski

Original Poster:

6,343 posts

189 months

Monday 27th June 2016
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Sometimes life doesn't go the way you expect it to. Sometimes bad things happen, and sometimes good things happen. Sometimes, things happen which initially start out bad, but switch to a positive, depending on the way you look at them.

I've got a million other readers cars threads going (because I have about a million cars) and most of them are old and French. Not this one though, oh no! This one is even older.....and Scottish! So what's the crack?

Long story short (I'll do the longer ones sometime in the future), I run a small workshop specialising in restoration (mainly TVR chassis) but also tinkering in classic and modern classic cars, as well as a plethora of kit cars and specials. A long, long time ago, a young man by the name of Tim came to me on the recommendation of a friend, and said that he had a Hillman Imp, and wanted to put an engine in it. It didn't have an engine fitted, it was basically a rolling shell he'd bought from a field:



He'd lusted after an Imp for many years, and this was the realisation of a dream! He asked if he should put a motorbike engine in, to which my reply (based solely on my own opinion) was no, you shouldn't. Bike engined cars are awesome on the track, and bike engines are just better than car engines in terms of technology. But on the road, where this thing was going to spend most of its life, the bike engine would be a pain. No reverse, little to no torque at low revs (BEC's often need revving to 5-6k revs, just to find the biting point as they're no longer trying to move 200kg of Kawasaki around). My advice was use a car engine, if it is to be a road car with very occasional track use. Next engine to be dismissed was one of the Imp's original innovative features, the Coventry Climax-based all alloy lump. Would be the cheapest in terms of a package, but would need serious tuning to achieve the 100bhp goal we had set. And it would be unlikely to be a reliable 100bhp, or certainly not as reliable as an engine designed to run 100bhp in the first place. That all said, both Tim and I wanted to retain the 'Impness' of the car. We've had literally 1,374 people ask us "Why didn't you fit a Subaru XXX or a Honda YYYY or a Dacia Sandero V8?" Well, the reason is because, at the end of the day, an Imp is what Tim desired, and if he ended up with a V6-powered spaceframe clad with Imp bodywork.....well, that's not really an Imp any more, cool as it may be. So it needed to still be 'Imp' in its DNA, even if the engine wasn't. And of course, we know more than most that if we went cutting up an Imp shell in a structural manner, we'd be well into the realms of the dreaded IVA test. We didn't want that!

And so, I had a brainwave. It's probably know by a few people on here that I have a serious condition called
'Likesrattlyoldfrenchitus'. This condition led to me considering a tenuous link - Peugeot. The Rootes group was bought out by Peugeot in the late 70's, Talbot name and all. I knew from my PSA obsessions that Peugeot used the Simca-derived XY engine (aka the suitcase, because it lays down flat) in the Peugeot 104, Talbot Samba, early 205 and early BX models, among others. They were available in 1360cc, and would yield around 80bhp. All alloy, quite light, sounded god-awful but generally quite durable and peppy. Trying to find one might be tricky, but I swear I'd seen the conversion done before. And so I Googled frantically 'Peugeot engined Hillman Imp' and found nothing on the XY engine. Balls.
What I did find, was a small thread on a forum regarding a Scandinavian ice-racing series. In that series, a limit of 1399cc had been set, and apparently the cars that were tearing up the field were Hillman Imps being pushed along by Peugeot/Citroen TU3 engines lifted from the AX GT and 205 XS. 85bhp, similar basic weight to the Climax and pretty tough. I didn't realise they'd fit, as they sit bolt upright, but a quick trawl of some Imp forums revealed that they did - just!

Could we find an AX GT engine? Could we feck! But the TU came in many different flavours, and one of these was the TU5 in the Saxo VTR 1.6 unit. 90bhp as standard, and pretty tough. Lots of midrange torque (perfect for munching Imp transaxles) and they engines were cheap. Hell, even the cars were cheap, so we bought a car!:



Only drawback, is that the TU5 only came in iron block flavour, unlike the all alloy TU3 fitted to the AX GT. With a weight penalty of around 30kg, we'd need to be clever to stop the car handling like a pig. In retrospect, the perfect engine would have been the TU2J2 fitted to the S1 106 Rallye, but they're even rarer. And more expensive.

The Saxo came with 120,000 on the clock, and no MoT. We popped it on the dyno before the engine came out, where it continued the Saxo tradition of bettering its book power figures (every Saxo to date has produced more power on the dyno than the book figures state!) 95bhp was the number, and the graph was strong (even if the radiator was not!)
The engine was duly removed and the Saxo discarded.

Now we had a square peg (a TU engine), and a round hole (an Imp). But the TU5 would get us to the 100bhp marker we set, and provide it reliably. So how to you make a square peg fit a round hole? Simple, you improvise:



We spent a LONG time to designing that!

Now we had a TU engine and a way of mounting it to an Imp transaxle. We came up with a hybrid clutch using Sierra bits and Saxo bits, along with a flywheel from a 106 Quicksilver. We had Reg Patten build a mk3 gearbox (the strongest casing) with a Ford-splined input shaft, to allow the Sierra driveplate to fit. Then we used Lotus Elan roto-couplings to connect the box to 1in Imp Sport driveshafts.
To push the TU5 engine into the 100+ club, we fitted some Honda Fireblade bike carbs (the standard injection system wouldn't fit), as well as a Newmans PH3 fast road camshaft, and Raceland 4-2-1 stainless exhaust manifold (standard VTRs use what is basically a 1.1 exhaust, possibly to strangle them a bit to bring insurance groups down). The ignition is distributorless, and managed by a Megajolt box mounted in the back. To keep the engine cool, an MGF radiator was installed up top, and I took and angle grinder to the front end to create a kind of 'custom' grille. Twin cooling fans keep the temps in check, and Evans Waterless Coolant circulates the pipework plumbed through the cabin (as the original Imps had radiators mounted in the engine bay) which is heat-wrapped and hidden below handmade GRP panels, carpeted to take the eye away from them. The rear seats are no longer there, though I would put some in if the coolant pipes didn't go there.

The rest of the Imp was also given similar treatment. All suspension was stripped, shot blasted and painted in POR15 before before fitted out with polybushes. The front drum brakes were binned in favour of Fiesta mk1 discs, Goodridge braided hoses were fitted all round, and the steering tie rods were upgraded to the Imp Club adjustable types. The body shell was fully resprayed in Vauxhall Karabic bue. Why? Because Aquarius metallic is harder to mix up, and the Vauxhall colour is 99.5% the same as the fairly rare Aquarius, just much easier to deal with if it needs any future resprays (which it does, already - more on that later!) We had the pinholes for the side mouldings smoothed over, along with the rear panel where we removed the bumper mounts and starter handle hole. Speaking of the rear panel, we braced it and fabricated an extended engine mounting boss, so we could utilise all the original Imp mounting points. The engine cover is a carbon-fibre piece, as is the front spoiler.

The entire build can be seen here in this blog we did along the way (apologise for some of the pictures - I got carried away with Picasa back in the days!)

And so where do we end up now? Well, life doesn't always go the way you plan. And so, as I said when I started the thread, we're at that point. Tim no longer owns the Imp, I do. Life came Tim's way, and shat at his doorstep. The alternative was to break the car up, as Tim couldn't stomach seeing someone else enjoying the fruits of his cash and our labour. If I didn't take it, nobody would. I couldn't bear to see the Imp come this far and not cross the finishing line. We'd covered around 100 test miles since January 2016, but still had (and still have) plenty of kinks and creases to iron out.
Yesterday, me and my wife took it to the Seven Stars near Petersfield, to see if we could take a run out in it without issue. We got there and back, though there are still issues! Even so, I took some pics at the end and this is where we're currently at:



The interior is half finished. I don't like the seats (have more period ones ready to go in) and the dashboard needs more of a dashboard! The binnacle itself is a custom-made six-dial version of a Stiletto dash, finished in black crackle paint (naturally). It comprises an oil pressure gauge (which doesn't work properly), a coolant temp gauge (which doesn't work properly), a speedo (which doesn't work properly), a rev counter (which DOES work!), a fuel gauge (which DOES!) and finally a volt gauge (which works, but is only there because it came in the box - will likely get replaced with an AFR gauge or something):




The 'frunk' (front-trunk) would usually be loaded with a spare wheel, a heater blower motor, a fuel tank and not much else. Now, it houses the radiator and cooling fans, an alloy fuel tank (which sits on a custom-strut brace), the electric fuel pump and pressure regulator. The two areas are split by a plastic bulkhead, which is there to prevent the radiator heating up the fuel tank. The spare wheel well has been opened up to allow warm air to pass through, and the lourves in the wheel arches allow the low-pressure air in the wheel arches to suck the high-pressure air out........when the car is moving anyway!) The splitter is carbon fibre, as mentioned, and the grille is an original Imp grille we cut up and hid some mesh behind (had the idea on the bog one night!) The headlamps are halogen-converted:




The business end! The Citroen TU5 lump sits with masses of space either side of it, as the original Climax lump laid flat. To fit it in, we had to remove the parcel shelf skin, but otherwise it fits fairly well, and nothing structural needed to be hacked out, which was important to us. The rear panel was a standard Imp piece which we customised into one being able to take a Spoox Peugeot 106 Grp N mounting plate. Spoox carbon fibre timing covers replaced the plastic (must have saved, ooh - 0.012kg there!). The gearbox is a standard mk3 box fitted with a custom input shaft, and uses original Imp mountings. We added a Mini stabiliser bar to the offside of the engine to aid stability, and the rear panel is braced triangularly, just for a bit of additional torque-resistance (we're going from 50lbft odd to around 100lbft):





To compensate the weight gain of the engine, the battery and radiator have moved off to the front. The Longlife exhaust system is tiny, and weighs very little. The carbon-fibre engine cover weighs around 1.5kg - around 5kg less than the original. Access to the engine is gained obviously though the engine lid, but can also now be gained through the interior of the car. This sound-deadening box we made from Celotex board, and insulated it against heat. It's mounted on a rear stiffening brace, which also houses the seat belt harnesses:



There is also a safety devices roll bar fitted.

So what's it like to drive? Erm, frantic! That would probably the be the best way to describe it. In terms of performance, it's probably on par with a 205 GTi 1.9 or a mk2 Golf GTI 16v - that kind of level, only with a lot more noise! The gearing is the weak link, really. It's only 4-speed, and the final drive is very short. 2000rpm equates to 30mph in top gear, and each 1000rpm increase equates to an additional 15mph, so 6000rpm is 90mph. Being that the limiter is at 7000rpm, top speed is basically a ton, so it's not exactly....refined. It pulls well, makes a nice old skool carb induction roar and plenty of soft pops from the exhaust on the overrun. It's very easy to drive in traffic, all controls are light and easy to use and it idles sweetly.
Handling? It's good! So much communication through the steering and through the car itself. You can feel the weight shifting around, but it's all well-mannered. That's at 7/10ths - on a qualifying lap it might be more of a handful, but it kept up with a new shape Mini being driven fairly briskly recently. Probably enough to make the driver look in the rear view mirror and think "Eh?!"
The gearchange should be sweet, but isn't. More work needed here as it makes some awful noises when coming on and off the clutch, and it tends to lose its oil. We always knew it would take a while to iron out the creases, and we suspect the concentric slave cylinder we fitted is to blame.
The brakes are equally as bad. So much so, I'm currently looking at a pair of old Wilwoods and some 5mm plate steel.
The suspension is surprisingly compliant. Riding Gaz coilovers at the front and Gaz adjustable dampers with standard springs at the back, it rides quite well. The suspension was quite advanced for a small car of the time, and it shows even today, where it rides better than something like a Metro, designed nearly 20 years later.

On the whole, it's a lot of fun. I love innovative, often overlooked cars, and I always wanted to own an Imp. The Imp was the first car to have folding rear seats (which I've removed) and using an all-alloy engine in a compact car was certainly unusual (removed that too). But on the whole, it's a good giggle and I'm looking forward to tinkering. Next step, new seats (I don't like the ones currently fitted that much) and I'll be ditching the gold wheels (again, not my cup of tea - Tim loved them though). Oh, and the engine needs to come back out to have a look at that clutch/gearbox issue. I'm aiming to get it to some shows and meets this summer though, and a couple of mags have been chasing for a feature for a while.

Cheers for reading the 'short' version hehe I'll try to keep this updated!

daniel-5zjw7

486 posts

59 months

Monday 27th June 2016
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You sir are very skilled!

I love these.. saw a really nicely prepped one on Ebay last year and just couldn't stop going back to it. And as an ex S1 Rallye owner, the idea of that engine in one of these sounds epic!! Though the VTR lump does the job fine I'm sure!

Haven't been able to look at the pics properly yet but will do later!

rev-erend

20,585 posts

242 months

Monday 27th June 2016
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In about 1982 - we put a 2.0 Ford pinto into a Singer Chamois.

It pulled great wheelies.

The gearbox was a VX transaxle.

gforceg

3,347 posts

137 months

Monday 27th June 2016
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I learned to drive in an Imp and I used to daydream about this sort of modification and performance.

Great work.

5potTurbo

9,322 posts

126 months

Monday 27th June 2016
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Wow! I haven't seen an Imp since, well, forever!
As soon as I saw the OP name I knew it had to have a French link. wink

AdamIndy

1,648 posts

62 months

Monday 27th June 2016
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I absolutely cloud9 that! Very well thought out and put together it seems. I bet it's a hoot to drive too!

Well done, the car is excellent!

Rsdop

419 posts

75 months

Monday 27th June 2016
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That is superb! Love a modified classic, and the fabrication looks excellent smile

Vitorio

4,296 posts

101 months

Monday 27th June 2016
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Excellent idea! and very good execution.

And good for now sacrificing a 106 rallye for a TU2 lump, those things are rare as fk!

Gallons Per Mile

964 posts

65 months

Monday 27th June 2016
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Superb! I love random engine conversions especially when they're done on old cars like yours biggrin

Smokin Donut

267 posts

184 months

Monday 27th June 2016
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SWEET! I love it. I'd put an pressed ali dash in, but I have a soft spot for them.smile

Kitchski

Original Poster:

6,343 posts

189 months

Tuesday 28th June 2016
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Thanks guys, some kind words to read on a Tuesday morning smile

Had the new seats arrive yesterday, so have mostly bolted those in place. They're much smaller, and fit pretty well. I've left the passenger one out so I can get access to the engine from inside, as I have a feeling it's going to have to come out again to try and figure out what's going on with this gearbox!

dom9

7,047 posts

167 months

Tuesday 28th June 2016
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That's fantastic! TU engine looks great in there biggrin

Cupramax

9,155 posts

210 months

Tuesday 28th June 2016
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Interesting thread, my first two cars were Imps, i remember them with some affection (probably through very rose tinted specs). I seem to remember the original Coventry Climax engines were canted over to one side, how have you found enough room to have the TU upright or am i missing something, is it considerably smaller physically? Will you be fitting a new sump every 5 minutes? Mine were absolute rust buckets even back in the 80's and had the front wishbone mounts literally rust/fall out on one yikes that was an interesting drive home biggrin

Kitchski

Original Poster:

6,343 posts

189 months

Tuesday 28th June 2016
quotequote all
Cupramax said:
Interesting thread, my first two cars were Imps, i remember them with some affection (probably through very rose tinted specs). I seem to remember the original Coventry Climax engines were canted over to one side, how have you found enough room to have the TU upright or am i missing something, is it considerably smaller physically? Will you be fitting a new sump every 5 minutes? Mine were absolute rust buckets even back in the 80's and had the front wishbone mounts literally rust/fall out on one yikes that was an interesting drive home biggrin
Yes, the Climax lumps were canted right over. We've removed the skin of the 'parcel shelf' which used to go in behind the rear seats (the structural framework around it is still there) and the TU engine it pretty much up against the underside of the rear member under the rear window (which is why it had to go to carbs - the original EFI setup wouldn't fit). The sump is visible underneath at the bottom, but it's not come into close contact with anything yet, and the car itself isn't that low at the rear as we've set it up for stability. That's why the front is so low.

It was pretty rusty, yeah. Has had sills, arches etc, though we farmed out all the bodywork to bodyshops in the area. A mate of mine painted it in a shed!

John_S4x4

1,327 posts

215 months

Tuesday 28th June 2016
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That looks like a fantastic build. Well done on all the hard work clap

I've owned Imps in the past and to drive they are great cars. To carry on fixing all the problems and issues for keeping them on the road - not so great. I currently own a Davrian and am thinking about the BMW K1200 motorbike engine conversion.

Shadow R1

3,542 posts

134 months

Tuesday 28th June 2016
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Some effort gone into that. smile

gregs656

5,671 posts

139 months

Tuesday 28th June 2016
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Your threads are always excellent. Love the Imp.

jhonn

1,105 posts

107 months

Tuesday 28th June 2016
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Nice job! Thanks, I enjoyed reading that - I remember Imps from my youth, they had some innovative features as I recall and punched above their weight.

What does the car weigh now? Can't imagine it's more than 800kg or thereabouts - 100bhp is nice to have in something so light and nimble - it makes me think British Porsche. biggrin

It looks very well engineered - well done. thumbup

Mr Tidy

12,390 posts

85 months

Tuesday 28th June 2016
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Fantastic write-up OP!

I love reading threads like this - seemingly random collection of parts beautifully put together to make something really unique! thumbup

Hope we get some future updates.

Kitchski

Original Poster:

6,343 posts

189 months

Wednesday 29th June 2016
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John_S4x4 said:
That looks like a fantastic build. Well done on all the hard work clap

I've owned Imps in the past and to drive they are great cars. To carry on fixing all the problems and issues for keeping them on the road - not so great. I currently own a Davrian and am thinking about the BMW K1200 motorbike engine conversion.
Cheers. The K1200 engine looks really right in the back for an Imp. Truth be told, it wasn't an engine that came to mind when we were planning to conversion years ago. Less peaky and revvy than the usual superbike stuff, should be good!

Shadow R1 said:
Some effort gone into that. smile
You can say that again!

gregs656 said:
Your threads are always excellent. Love the Imp.
Very kind, thanks

jhonn said:
Nice job! Thanks, I enjoyed reading that - I remember Imps from my youth, they had some innovative features as I recall and punched above their weight.

What does the car weigh now? Can't imagine it's more than 800kg or thereabouts - 100bhp is nice to have in something so light and nimble - it makes me think British Porsche. biggrin

It looks very well engineered - well done. thumbup
They were innovative cars, for sure. Cars that bring something new to the table always strike a cord with me, even if they're much maligned. Ironic thing is I've removed some of the innovation by whacking an iron block in it!
Weight? Not sure. Want to find out though! Should guess its around 750-800kg wet, so yeah 110bhp or whatever's probably giving it 140bhp/ton or so.

Mr Tidy said:
Fantastic write-up OP!

I love reading threads like this - seemingly random collection of parts beautifully put together to make something really unique! thumbup

Hope we get some future updates.
We've got a lot of experience with kit cars, and I'm originally a car spec/history geek who also used to work in car parts, so I often get ideas about what could fit here and there.

I'll update it with some more details and images of various aspects sometime soon. There's loads I've missed out, like the Toyota MR2 SW20 throttle linkage!