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

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

Author
Discussion

HerbertD

28 posts

101 months

Wednesday 29th June 2016
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Loving the concept as I went through a similar process some years ago with a Ford CVH 1600 engine shoehorned into a Sunbeam Stiletto. Went well, but handling was challenging to say the least. I posted some details & photos of this some years ago : http://www.pistonheads.com/gassing/topic.asp?t=125...

Full respect to you as your conversion looks fully sorted and nicely finished!

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Cupramax

9,148 posts

210 months

Wednesday 29th June 2016
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Nice Stiletto but what does a large lump of Ford pig iron do to the handling? The standard imp engine was all alloy and weighed hardly anything.

HerbertD

28 posts

101 months

Wednesday 29th June 2016
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Yes, it certainly did'nt improve the handling, that's for sure! To be fair, the guy that I sold the car to was going to convert it back to the standard engine to go historic rallying. He was based in Southern Ireland, so I don't know what happened to it. It would be interesting to see if it still exists.

Baron Greenback

4,787 posts

108 months

Wednesday 29th June 2016
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Awesome idea, I doff my hat off to you!

vrooom

3,752 posts

225 months

Wednesday 29th June 2016
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This is awesome. i love those kind of car. i love rear engined cars.

Kitchski

Original Poster:

6,342 posts

189 months

Wednesday 29th June 2016
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HerbertD said:
Loving the concept as I went through a similar process some years ago with a Ford CVH 1600 engine shoehorned into a Sunbeam Stiletto. Went well, but handling was challenging to say the least. I posted some details & photos of this some years ago : http://www.pistonheads.com/gassing/topic.asp?t=125...

Full respect to you as your conversion looks fully sorted and nicely finished!

[pic] [/pic]
[pic] [/pic]
Now that's interesting to see. I've never actually seen a CVH one before! The TU to PSA was basically what the CVH was to Ford, only with the TU they covered everything from 950cc up to 1600cc. Ford continued to rely on the old Kent lump for the smaller stuff (there could be confusion here, as the Kent/Pinto/Cologne engines are the old tech heavy ones, generally referred to as 'pig iron'. I know the Cologne with the type 9 box that I have in my TVR stressed the engine crane out much more than an S50 BMW M3 lump and 6-speed box!) The CVH was a bit more modern, and I'm pretty sure it had an alloy head (just because of the era of it) but could be wrong. The engine in the Imp is an iron block/alloy head, and though I would assume it's a bit lighter than a CVH, I doubt there's that much in it. The Beetle transaxle will make a big difference, though, as those things are HEAVY! They're reinforced as on a Beetle or Camper, the engine hangs off the back of the gearbox, with no engine mounts, so the gearbox casing has to be pretty heavy duty to handle that. The Imp transaxle is only 29kg or so, but then this engine may yet eat it!

Handling feels pretty good on the Imp though, so far. I estimate it's probably running a penalty of around 15kg at the rear, over a standard car (once you add the engine weight, then deduct all the bits that have been relocated or lightened). Then on top of that, we've got the front spoiler (not sure how much difference it makes with downforce!), the nose down/arse up rake of the suspension which rides pretty softly on the front axle (I hate the negative camber look, but it works in this case). The tyres are also wider than the normal Imp spec.

Would be interesting to drive a standard one for comparison. I've never driven a normal Imp!


Edited by Kitchski on Wednesday 29th June 14:36

Kitchski

Original Poster:

6,342 posts

189 months

Friday 1st July 2016
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I was planning on updating the thread in a different manner to the usual. Because the car has had so much work, and so many new designs etc, the 100miles or so that it's covered since it was built are really test miles, and the car is still being tweaked. I've got a small list of big issues to put right at the moment:

  • I've got suspected fuelling problems with the carbs
  • I've got some pretty bad bodywork issues, caused by the guy who did the panelwork on it prior to the paintjob (carried out by a different guy)
  • I've got clutch/transmission issues.
Everything else is stuff I can sort later on. Stuff that doesn't really hamper my use of the car. I did change one non-critical bit, though! OMP T-RS Legends (left) out, OMP Brands Hatch (right), in:



Never really liked the full buckets, in terms of style and in terms of fitment. They were MASSIVE in the little Imp. They'd be great in something a bit bigger, but I wanted a more old school look:



They match the OMP harnesses, and OMP steering wheel. I could be sponsored by OMP!:



They also have corduroy centres. Win:



Anybody want to buy a pair of seats? All funds go to a good cause hehe :

Moderator edit: no advertising please.

So on to more pressing issues - gearbox.

The transaxle I'm running is the standard Imp transaxle. It's very light (good), very short geared (not so good) and fairly weak (obviously a bummer, but not so much of an issue if you're sensible and don't try to jump from about 45bhp to around 110bhp).
The idea with the conversion was that if it chewed a gearbox up, we could replace the engine with a 1400, 1300 or even 1100cc version of the TU in preparation for the next gearbox. Or, we could upgrade the gearbox, but unless you want to spend £3k on a 5-speed Jack Knight dog-box, that's going to involve cutting and shutting something. Or, Tim (now me) could just learn to drive a bit smoother!

Now, we have transmission issues already, with around 100miles covered. Or rather, I suspect we have clutch issues. The gearbox is dropping oil from the bellhousing area, and when fully depressing the clutch pedal, you hear a nasty grounching kind of noise. Trying to select gear can make this worse, but not by much. It'll do it in neutral. Let go of the clutch, and all is quiet again. Gear selection gets worse the more you drive the car.

So we have a problem! The original Imp setup used a slave cylinder, release arm and normal clutch (first car to have a sprung centre plate I believe - more innovation there, innovation fans!) In order to run the TU, we had to improvise!
We used a modified Imp input shaft, found purely by chance on an Imp forum. It had been made to accept a Ford-spec clutch plate, so that's exactly what we used - a Ford Sierra 1600 clutch plate, turned down around 5mm to mate up to a Saxo 1400 clutch cover (which was designed to use a 180mm clutch, not the 200mm of the standard VTR spec. Because of this, we dropped down to a 1400 flywheel too, which came from a 106 Quiksilver (on the bay of E, at a cost of £10, posted!) We had to drop down to a 180mm clutch as the 200mm one wouldn't fit inside the Imp gearbox bellhousing! So, we sent the shaft away along with the rebuilt Reg Patten gearbox, back to Reg Patten for him to install the new input shaft.



When it came back, we fitted this:



Concentric slave cylinder. At the moment, it's my belief that this is the unit at fault. Why, is anybody's guess. Worst case, the gearbox doesn't like having the load of the clutch against it there, and has fractured (causing the oil leak). Best case scenario, the design is fine and it's simply a faulty unit.

We'll find out tomorrow, when I pull the engine out and have a look!

Edited by jeremyc on Friday 1st July 08:04

Chris Stott

7,949 posts

155 months

Friday 1st July 2016
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Haven't seen an Imp for donkeys years.

In my late teens, a mate had an Imp with an engine from Greetham Engineering. My abiding memories are how loud it was, how fast it was, the constant smell of Castrol R and how many drive shafts it broke.

Kitchski

Original Poster:

6,342 posts

189 months

Saturday 2nd July 2016
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So Friday saw an attempt to figure out what the gearbox issue is. Engine and gearbox to be removed, which begins by access the back of the engine via the interior of the car (aha! Stick that in your hash-pipe Hillman!):



Engine and box out (again):



Engine and box split:




Trying to work through my head as to what could cause the issue. The issue being a loud groaning sound, matched to engine revs, which arises when you press the clutch pedal down. I had visions of the release bearing failing (it has, as it goes - or the bearing part at least) or something grinding away on something else. I didn't stop to consider the thrust bearing, which looked fine on the face of things:



But rattled around in the end of the crank like a prick in a shirt sleeve! This is why:



150miles down the line, it's knackered. So why?

Well, the Imp transaxle has a very floppy input shaft (ooh err!) Stood alone, there is no bearing support and the shaft flops around. It's designed to engage at the very end into a bearing at the end of the crankshaft, which a Climax lump used.
The Saxo setup is different. There is no play in the Saxo's input shaft, and they don't use a spigot bearing. Because of this, we had to make one from phosphor-bronze, which we then bonded into the end of the Saxo crank. It looks like the epoxy we used didn't really hold up to the job, so on Monday I'll be popping down to see the boys at the local engineering works and see if they can make me one which is more of an interference-fit. Stick it in a freezer while heating the crank up in preparation, kind of thing.

Fingers crossed, that was the issue with both the noise and with gear selection.

Markgenesis

396 posts

90 months

Sunday 3rd July 2016
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Love this, i was into Imps about 15 years ago, had a few including a very rare Commer Van, one thing i always found frustrating was the cost of tuning bits and engines, (£1000 back then for a 998 bottom end), common thing was to use the Sunbeam 940 bottom end with Sport head and cam, the engines are jems though, my main one (a Californian coupe)had a standard Sport engine with a Janspeed manifold, MK2 Fiesta front rad and MK2 Fiesta discs was my only car and a daily driver.

I can confirm the Imp engine is very light, i built the Sport motor in our spare upstars bedroom (no garage at the time) then carried the whole thing downstairs myself and out into the drive laugh

Stunning little car, hope you get the bugs sorted.

Keep the updates coming.

Kitchski

Original Poster:

6,342 posts

189 months

Friday 11th November 2016
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Just realised I never updated this!

So what's happened so far? Well, I had to go on a speeding awareness course, as the trip to the Seven Stars with the wife resulted in being zapped by a man in a van! Speedo wasn't working - it's a fair cop!

Since then I've removed the engine, installed the new spigot bush, refitted the engine etc and made a few tweaks to the layout. Horrible noise coming from spigot bush gone, but now the clutch is not working properly, and I have a torrent of DOT5.1 hitting the floor. Time to drop the concentric cylinder and explore other ideas.

I've also sourced an original mk2/3 dashboard, as I'm not really loving the non-dash the car currently has. Plans are to get a mate to flock it, tart it up with some carbon fibre and tit bits and go from there. I want to keep the electromagnetic indicator stalks though - they rock.

It also needs some bodywork to sort out the mess the first bodyshop guy made of the doors, but I suspect this might have to wait for a while.

Oh, and the wheels are no longer gold:


Jellyfish

52 posts

90 months

Sunday 13th November 2016
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Good effort. Hope you get the issues ironed out so she gets seen out and about a lot more

Kitchski

Original Poster:

6,342 posts

189 months

Thursday 23rd February 2017
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Time for an Impdate!

Work has resumed on the Imp, mostly because it's immobile and in the way, and I need to get it out and home again. If that means fixing it so it can be driven and enjoyed again, so be it!

The main issues currently concerning the Imp are:

1) The clutch, which didn't work and needed a re-think
2) The interior, which I wasn't mad on, and needed a rethink
3) The bodywork, which needs sorting!

Of those three, the bodywork is the least important. It won't be done any time soon, mostly because funds don't currently allow. The issues aren't the paint, as on the whole it's a beautiful paint job. It was done by a mate of mine, though if he spots the bit he didn't quite cover properly under the driver's door on the sill, he'll kick himself!
It'll be sorted when the bigger bodywork issues are sorted, namely the fact the panel gaps around the doors are atrocious! They were done by a bodyshop on my workshop's industrial estate, and they are shocking! I shouldn't be surprised, as I've had similar issues on another car I had done there. Still, you live and learn!




I also found that he'd used a fair bit of filler in the front arches, when the front tyre tried to knaw a chunk off:



Anyway, as I say the bodywork will have to wait. What's more important is getting it to drive right! The interior will come later.

Those who've been following the thread will remember I've had issues with the concentric slave cylinder arrangement we first used. The setup had its advantages, as the bearing had its own guide so to speak. It exerted the force directly onto the clutch, with no other moving parts. Great!
Only not. The issue has been getting the thing to stay leak-free. The unions had leaked since day one, and once I'd finally got those to seal, the main seals themselves decided to start weeping. It could probably be fixed and used again, but I've given up on it. The main problem is that each time you want to do anything with it, you have to take the bloody engine out and take the gearbox off! It's not that hard, but after the 3rd time it gets pretty boring!

Originally, the Imp used a hydraulic setup, with a slave cylinder pushing on a release arm posted in from the top of the bellhousing, thus:



I decided that I would go back to this tried and tested layout, but realised there was a problem fairly early on; The original Imp engine is canted over, and the Saxo engine sits bolt-upright. This means that there is an engine where the Imp slave cylinder needs to go. Bum.

I looked into 'pull'-type cylinders, that I could mount on the opposite site of the release arm. I looked at making a cradle for the standard cylinder to sit inside, in front of the release arm (so that when extended, with would drag the arm in the right direction). However, salvation was at hand, in the form of Car Builder Solutions! They offered a very slim clutch slave cylinder:

{url]http://www.carbuildersolutions.com/uk/flat-backed-clutch-slave-cylinder[/url]

With one of these, I might be on to something! I ordered one up, adjusted it so it fitted and offered it up. it fitted! The only issue was that the cylinder sat slightly higher, which then meant I had to cut the top off the release arm I'd found, and attempt to extend it:




Once I'd extended it up to the height required to meet the cylinder, it was looking promising!



That was the top taken care of (and yes, I've done some maths and it will extend far enough to disengage the clutch - I even measured how much travel was needed to do this:



I even filmed it in action! Only needs about 5.5mm of movement from the would-be release bearing to completely disengage:

https://youtu.be/DqXUdgtYQhw

The original Imp setup, however, used one of those 'orrible graphite bush-type affairs, rather than an actual bearing. Aside from being awful, this is incompatible with the clutch cover, being a TU 1.4 setup.



So I set about trying to remove the carbon/grahpite bush from the Imp's release mech so I could attempt to convert it to a bearing-type setup......and broke it.

I have no pictures of this. Honest!

I wasn't 100% sure that this was the best way to go, as there would be more work to be done trying to extend the release mech out to reach the clutch (baring in mind the adapter plate between the engine and gearbox means everything has be extended forwards the same kind of distance), but with no other ideas immediately at hand, I decided to get another bearing in to see where I'd end up. I had a stroke of luck, as by chance I discovered MG Midgets (with the A-series lump) use a similar setup, only slightly deeper:




I drilled the retaining clip holes and successfully removed the graphite from the housing:



It now fits the Imp release arm:



It hasn't won me all the extra clearance I needed to make up for the adapter plate, but it's a step towards it. However, I'm now at another crossroads. You can see in that pic above that the release housing is drooped over - the centre of gravity just can't keep it upright, even with the standard Imp bearing.
The issue is that once the clutch is fitted and everything's in place, the top of the bearing is going to constantly be resting against the clutch fingers. Now there won't be much weight against it (not unless I use the clutch as a footrest like a numpty), so in theory the bearing should be OK. To be fair, even if it did shorten the life of it to something like 15,000 miles, how long exactly is it going to take this car to do 15,000 miles?! It'll be 15years I expect!
Even so, it bugs me. I like the idea of using a sleeve for the bearing to slide up and down, like on the original Saxo setup, but the problem is the release arm has fixed location points to the bearing; It won't allow it to move back and forth as it's trying to move in a small arc, and when sliding up and down a sleeve there is no room for an arc, with or without all the animals and floods and Noah and st.

So my thought processes at the moment are:

  • Do I need to fit a sleeve, and in doing so have to redesign the release bearing setup and how the arm operates it.......again
or

  • Can I just have a spacer made to go between the existing release housing and the current release bearing, and live with the arch it sweeps in an arc?
Decisions!

davepoth

29,395 posts

157 months

Thursday 23rd February 2017
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What about putting a "bump stop" inside the bellhousing so that when the arm is in the disengaged position it prods the housing from the back and forces it to be vertical?

Kitchski

Original Poster:

6,342 posts

189 months

Thursday 23rd February 2017
quotequote all
davepoth said:
What about putting a "bump stop" inside the bellhousing so that when the arm is in the disengaged position it prods the housing from the back and forces it to be vertical?
I did wonder about something like that this evening. Just something for it to park against when the pedal's off. I'm planning to fit a return spring to the release arm, so it might work well with that.

AyBee

9,177 posts

160 months

Friday 24th February 2017
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davepoth said:
What about putting a "bump stop" inside the bellhousing so that when the arm is in the disengaged position it prods the housing from the back and forces it to be vertical?
I like this idea - was also going to suggest adding weight to the bottom to change its centre of gravity.

TimmyJK7

13 posts

53 months

Monday 20th March 2017
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Great write up Rich! It is still very upsetting to not owning this but I know it is in the best of hands. I cannot wait for this car to be finally finished and being enjoyed on the roads! Good luck Rich!

NiceCupOfTea

25,000 posts

209 months

Monday 20th March 2017
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I love this. My dad had 2 Imps in the early 80s, a bog standard one and an Imp Sport (Stiletto engine), lovely things. I can still feel the hot vinyl seats on my legs in the summer and remember the clang of the doors cloud9





Can't tell from the pics, but one of them is pretty much the same colour as yours!

rallycross

11,010 posts

195 months

Monday 20th March 2017
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I have seen this car and I love it but I cant help think that heavy lump from the Saxo should not be in there!

The original car had the lightest of engines, alloy, compact, light, just like an AX GT engine - if anyone can do it you can Rich, a lightly tuned Tu3-S on twin 40's would be ideal!

dom9

7,047 posts

167 months

Monday 20th March 2017
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rallycross said:
I have seen this car and I love it but I cant help think that heavy lump from the Saxo should not be in there!

The original car had the lightest of engines, alloy, compact, light, just like an AX GT engine - if anyone can do it you can Rich, a lightly tuned Tu3-S on twin 40's would be ideal!
Now, if only he had an AX GT going spare... wink