1965/67 Hillman Imp pick-up (fixings, dynamo, run-stand)

So I fianlly got back to working on the Imp this week after the usual chore of earning money. Still I paid off £800 towards my credit-card so the the plan of clearing my debt before end of April is pretty much ehm - going to plan

This (hopefully) means May onwards I can do ef-all apart from work on the Imp and get into lots of debt.

So yeah. I got back to fiddling with the engine-stand but also bought a dynamo along the way.

I think I said above about the alternator having different brackets(s) and the fact it's not original to my car anyway and I figured as most Imps had dynamos it would be easier to mount one of them which means I could get on with the job of getting the radiator built into the stand.

Also as the alternator isn't original to my car the wiring might not be right for it so all in all it seemed like a good idea to get a dynamo and I got one on Ebay for £30.50 (inc P&P). It arrived very quickly so this weekend I bolted it on.

It doesn't actually alter the position of the water-pump but everything is secure so I then mocked-up the fan-shroud, gaiter, radiator and rear cowl.

It was clear the rear cowl will foul the rear part of the stand but I don't see why this would need to be fitted anyway so I'll forget about that

One thing I found after mounting the dynamo, pump etc was that the extra weight makes everything want to tip over. This means I'll need to re-examine the feet I put on last time.

After mocking-up the radiator etc it struck me that the best way to establish exactly where it should sit would be to attach the top and bottom hoses. I did that today and now have ideas about how to mount the radiator....

I think I will put a piece of bar coming from the rear-stand over to the inner-top radiator-tab with another bar welded at right angles to it, which I can hang the radiator from. Don't think I'll need supports at bottom too - but we shall see.

The dynamo is a C40 which I think is correct for the Imp and I bought it off a guy who is well into Imps. However the parts list shows the type fitted was C40-1. Interestingly the Sport or twin-headlamp models got a different one C40L and it had a different mounting bracket. I'd noticed this in the parts list before and wondered why that could possibly be then read the other day that the L one was longer which would .'. require a different bracket. Seems obvious now



Lucas C40 dynamo



rear support bracket for generators differ. painted one is for alternator



dynamo goes between front and rear brackets


dynamo bolted in



fan-cowl connects to gaiter connects to radiator (front) shroud/cowl



cowl connects to radiator straps



rear cowl connects to radiator straps but would foul engine-stand




hoses and block of wood used to find position of radiator before making more bracketry

For the rivet-pickers following this thread here are some pics of the bolts that came with the dynamo. They are all correct thread (5/16 UNF 24TPI) and seem to be correct length. " of them are definitely correct to an Imp as they have the AUTO thing cast on the heads with the ring (which denotes UN thread) but the longer one is different and its nut has a very unusual sort of triangle stamping on it.

The short bolt which connects the adjusting-strap to the dynamo was a bit mullered and I spent quite some time dressing the threads back into the end of it with a thread file. I couldn't get the die to catch on it as the threads were flattened out as well as being dirty. It looks ok now but you can see the end is thinner than it should be. The tapping in the unit was also full of corrosion or something and it did clean-up with a tap but the fit is a bit loose. I think the bolt was forced in and corroded so it'll never be quite right but perhaps with a better bolt or even just putting a nut on the back it will work. I could put a thread-insert in it I guess but that'll prob cost more than another used unit


dynamo has 3 fixings. casting is threaded for adjusting-strap bolt


adjusting-strap bolt head



similar to rear-mount bolt head



front-mount bolt has different markings on head



and unusual stamping on nut



adjusting-strap bolt after re-dressing threads




thread in casting is a bit weak

So a couple more steps in right direction and probably one backwards

First of all I got a new (used) oil pick-up pipe for £10 (plus £3.99 P&P) on Ebay. You may remember my original one is loose when it's supposed to be permanently fixed to the casting. I can either use this new one or re-secure the other one now I have a reference item (for the position of the tube)

So making this run-stand for the engine a small hurdle was that the starter-motor doesn't readily bolt to the engine - because the threads for its bolts are in the gearbox casing. You .'. need some bolts plus nuts. Keeping it in the family (and having no suitably-sized metric ones anyway) I went for Imperial ones (3/8 UNF x 2 1/4") which were long enough to get through both components but not foul the frame of the stand. It was £5.99 inc P&P and that included nuts and washers.

I guess I must have the full set of bolts somewhere (in the gearbox casting perhaps) but would have needed nuts anyway. Funnily enough I started going thru a tub of Imp bric a brac I've had for about 30 years and found loads of nuts, bolts and washers but only a couple were 3/8". I'm pretty sure these aren't from my own car as they were in with a bunch of stuff I got when I bough the Imp. Anyway I spent a few hours one afternoon cleaning and sorting them all and am sure they are Imp as nearly all of them have the 'AUTO' brand name stamped on the heads.

That brings me to my next point...

In the tub of spares was a wiring loom and a control-box. Thing is the loom colours didn't match any of the wires hanging on to the box. I posted on an Imp group about this and someone explained the loom is actually the front harness for a late Imp with printed-circuit on the binnacle.

While making my run-stand I'm been thinking it would be good to have it wired neatly with same colours as factory but not having a spare to hand I decided to wheel-out (well, wheel-forward)Lonesome George to see what I need. It was a great feeling pumping up the tyres and moving him from his slumber thinking he might finally come to life. Even tho it was only a couple of feet. With this great weather we've been getting and the area under him sweeped out for first time in over a decade I felt like it's all do-able.

There isn't much to an Imp's wiring (thankfully) and everything was pretty dirty so I couldn't make out the colurs etc but a day or so later I started deep-cleaning the whole 'engine-bay' and the wiring to see what was what.

I then remembered the guy I bought a lot of Imp stuff rom last year had a box of wiring and control-boxes so contacted him and we arranged for me to go today. I told him I'd pay up to £50 for good stuff like complete looms and boxes) and less (like £30) if the looms were cut or damaged.

Anyway I got there today and the bag of stuff was a bit of a disappointment. There were 3 control-boxes (which sell for about a tenner) and a tangle of random wires. Some of it was household or speaker wire but there seemed to be some pukka stuff in there so I gave him £20 for 1 box and all the wiring. He didn't seem too pleased but I di ask first how much he wanted.

Anyway I got the stuff home and separated all the junk from it leaving me with a pile of 'might be Imp' to examine further.

One amazing thing was I found the 3rd bit of Chamois wood-capping in the bag . Last year I bought the dash-panels and wood off him and the small LHS piece of wood was missing







oil pick-up pipe




no holes in mesh



3/8 UNF bolts to mount starter motor to bellhousig



starter now securely attached to engine



and bolts not fouling frame




lots of Imp fasteners found



spare front harness is no good to me



my original rear wiring as found



original wiring clipped to bulkhead



cleaning engine bay


cleaning wires (oil & water senders)



wires cleaned on RHS of bay


wiring LHS of bay




control-box in spares has no brand name or part number on it



looks good inside



my car has plug for alternator



£20 worth of tangled wires and a pukka Lucas RB340 box



pile after removing obvious junk

So I have my front & rear parts of the 'run-stand' basically done, plus the thing for hanging the radiator, and am now looking at incorporating something to securely hold the electrics needed to start and run the engine.

I know I could have it held together with clothes-pegs and stuff and touch the battery lead to the battery to work the started and have the coil-wire stuck on the terminal etc etc but I'd like to be able to turn a switch just like in a car.

On top of this I think it's a good idea to connect the front & rear frames for rigidity as I want to be able to move the thing around. The rear frame is actually rock-solid but the front only has one possible connection-point to the engine so it's never going to be very 'secure'.

There's no point welding bars between the two frames as then the engine is trapped inside and wouldn't be easy to store when not in use so am looking at something that can be quickly and easily clipped on. I want to keep nuts/bolts/clamps/pins to a minimum, especially loose ones, so decided to try again using a sort of fixed tight fit system which worked surprisingly well on the radiator support thing.

Regarding the 'electrics-bar': There are really only 2 or 3 things I need to include which are the starter-solenoid and its wiring plus the ignition-coil (and possibly an ignition-switch and the battery itself). I feel it's a good idea to have the things in roughly the same orientation as they are on the car's body so had a look in the engine bay and saw how close they were to the radiator-support tabs. They are almost in-line with them

Looking at my frame there was an open end in the box-section at the radiator-support bar. The electric item won't weigh much so there is no need for another bit of square tubing and I have plenty of the flat bar to use so I stuck a length in there and it looks like a good place for it. I've not decided what angle to put it in at and will need to make up brackets, or drill it, for the coil & solenoid but it seems like the ideal place.

Next I had to find a way of connecting the frames with out fouling other stuff (including the electrics-bar) or making the thing a lot bigger. I was drawn to another open end on one of the original bits of frame. The sloping piece of the rear frame looked ideal.

Buoyed by my success with the external clamp idea I thought I'd try doing an internal one. Basically like a tube inside a tube so the new top-bar could just be pushed inside this part of the existing frame.

It would be tricky to cut 4 strips of metal and somehow hold them inside the square tubing before welding them so I firstly slit a piece of tube down all 4 corners them squeezed them in then welded them inside the actual tube to be used then cut off the bit I didn't need.

I have to say it hasn't worked as well as the external one. Even with making sure the fingers are pushed out enough to make the insertion tight it seems a bit loose. Maybe not long enough bit the bolt securing the rear-frame to the engine limits the length of it.

Another obstacle I had to get round was the radiator top-hose which was right above this area. I didn't want the frame pressing against the hose so decided to go the long way round with lots of mitred joints to get the bar eventually heading over to the front frame.

It's quite time-consuming to cut all the mitres without a jig without having to them compensate with the welding for joints which are too tight (lack of penetration) or to wide (welding fresh air) but 6 cuts later I was round the hose and it's still pretty true



I want a bar here to mount the solenoid and coil on to



scrap piece of bar showing how I hope to connect front & rear frames without fouling elactrics-bar



handy start point on rear frame but radiator hose is very close



going underneath would be very tight



piece of tube slit to make fingers to fit inside tube



fingers tacked into 1st part of new frame



fingers welded and rest of tube cut off



maybe not tight enough



1st part of new frame-section



top-tube now clears radiator hose

So one of the first things I'll need to have functional when firing-up the engine is - the starter-motor

I have obviously had it in my hand, mocking-up the stand, but have never actually looked at it or tested it. I therefore spent some time on YouTube watching other ppl rebuild them and it looked do-able .

I have to say for over 3 decades I've always had in my mind 'pole-shoe screwdrivers' after seeing in many old manuals pictures of some heavy-duty clamp/vice type thing that hold the (electrical) item steady while you wind down an integral screwdriver to shift the large screws on the casings of dynamos and starters. My reaction every time was/is 'how the fk does anyone get one of those things? to use once '

However we now have the internet and you can get anything on that so I had a quick look and didn't find anything, apart from other guys trying to make workarounds.

Anyway - back to my starter. I could feel the pinion/spinny-thing on the shaft was stuck so knew it had to be stripped anyway.

In the YouTube vids I saw the guys spent a lot of time arsing about with the Bendix spring trying to compress it to remove the little snap-ring on the end of the shaft. They did it with small vices or large grips.

I decided to try doing it on my press and it went very well. You don't need any pressure really but obviously you need to be able to see the clip under whatever you put on the spring to compress it. A socket would be no good so I tried the remains of a (Mondeo) front wheel-bearing inner-race with and old washer and a bit of flat metal on top. It worked fine.

After you have prised the clip off you can remove a big washer and the spring itself.

Then you should be able to remove the inner worm-drive and the pinion itself. I had a bit of bother here as they were stuck but after some gentle persuasion and judicious filing of burrs on the shaft-splines the worm came off. I haven't got the pinion off yet. It seems there is a bit inside with cut-outs that needs to match the splines but I can't get them to align. The teeth on my pinion are a bit knackered and it seems you can get new pinions quite easily so if it won't come off I'll cut it off. I'm guessing something inside the pinion is damaged

After hitting this stumbling-block I turned to the legendary pole-shoe screws. I wasn't going to spend the next 2 years searching for the tool, and figured you could pull them out with a welder anyway if things got really bad, but none of this was necessary. I used my Blue Point #4 Phillips bit on an old-fashioned impact-driver then, when I felt I'd hit it as-hard-as-I-could-without-breaking-something several times, I used a short breaker-bar on it and they all came out fine

Although I couldn't get the pinion off I could still take the armature etc out of the body as there is an alloy end-cap on both ends. There are 2 long screws holding them together with the body in-between. Theses screws also came out no probs with no damage to the heads.

These dynamos are (mostly) equipped with a metal band round the top which cover holes in the casing that are like windows where you can see the brushes and their springs. I'm not really sure how useful this feature is as you can't (afaik) actually service the parts when they are inside the unit so perhaps they were just a quick way to check if further action was needed. The small screw & square nut for the band was soaked in ATF a couple of weeks back so it undid fine.

With the armature out and the pole-shoe screws removed the pole-shoes drop out which means you can then remove the poles (field-coils?) but first you need to remove a series of washers etc from the stud/terminal that sticks thru the end-cap.

I think the coils (poles?) are quite fragile and was having a little difficulty getting the 2nd nut of the terminal and could feel it twisting a bit so spent quite a bit of time dressing the threads with a thread-file to get the nut off without damaging the coil(s). The stud didn't appear to be any of the UNF/UNC sozes I have in my set but seemed to be 28TPI which was on my thread-file.

Once the poles/coil assy was out I put all the small fittings back on in correct order to avoid problems later. One item did break tho. It's a white plastic collar/insulator that is no brittle but I see you can get new ones on Ebay so no big deal.

Removing the coil assy I had to release the brushes which are soldered/fixed on to it and it's quite fiddly getting the springs off without damaging the wires the brushes are on.

When i went to tackle the 2 remaining brushes on the end-plate I relaised the plate actually comes off the body, like the other one, which makes it easier to do but I still manged to nick one of the leads.

So that is the whole unit basically apart and now I need to decide if it's viable to replace the brushes or if they even need replaced. They are obviously worn but I don't know what the wear-limit is. I think I saw something about 8mm the other night and they are a lot longer than that still.

I can see brushes (c/w leads) on Ebay but not sure how hard it would be to change them. They looked like they are sort of built into the unit rather than being soldered.

Another small point is the insulating paper thing inside the unit. On a video I saw there was a much bigger one that had a dent in it so you knew exactly where it went back in the body. Mine is just a simple oblong and I'm not sure where it sat but I think its job is to prevent the coils terminal and brush-wires from touching the casing so that should make its position clear when I reassemble the unit





workshop-scrap (violet dots) used on starter in press to compress spring



bearing race with cut-out to give access to shaft


clip released


clip then space then spring


underside of spacer


large split washer sits between spring and pinion



worm-drive, shaft and pinion all a bit stuck



burrs on splines stopping worm from coming off


pinion should come off shaft after worm


something inside pinion is preventing it from coming off shaft


teeth on pinion are a bit knackered



I expected these to be impossible to remove



this bit seemed to be best fit for pole-shoe screws


impact-driver seemed to help loosen screws


screws came out fine


removing this band gives (visual) access to brushes etc


this is probably worn carbon rather than a paper insulator


long screws holding end plates on to body of dynamo also came out no problem


armature removed from body with pinion-side end-plate still on it



special washers fitted both ends of armature


view of poles, pole-shoes, brushes etc inside body



these nuts etc need to be removed to withdraw poles from inside body


fittings in order removed


pole assy removed from body


2 of the 4 brushes are soldered to the poles


small plastic collar from pole terminal broke


fittings back on terminal along with plastic collar (violet) and metal collar (orange)


other 2 brushes (violet) are attached to end cap. coil brushes go into other (orange) positions



end-cap complete with 2 brushes removed from casing






brushes have consecutive numbers on them


brush appears to be mechanically fixed to end-plate


spring/brush posts are heavily insulated from end-cap



need to work out where paper insulator was originally positioned