1965/67 Hillman Imp pick-up (bonnet repair)

Back in the day.... Say around '82/5
I was hooning about in an 875.

A local bash n bang garage had a Sunbeam 930 engine as scrap... I think the guy upsized his car. I got the engine for washers and stripped it >> I had a spare 875 block so dropped it into a local block shop and just said 'bore out to fit pistons' (about £35). I put a 875 sport head on [with a 930 Reinz gasket] and 875 bottom end...

Never had any trouble with the gasket/leak/fail... Was a nimble thing.
533KNX

I bought a 998, from a striking miner, that was for a chair combo = never had a pilot bearing fitted as they run a belt pulley!
Wills ringed, R20... What a Rocket
884KOE

OVIMOR

Hi there Darkspeed

I got my head out to take some pics and measurements and I'm pretty sure mine is '875 compliant'

I may not have measured exactly where you did, as there is no carbon on the face of my head to show the bore-size, but measuring the recessed oval (combustion chamber?) where the valves live I get just over 67mm.

I also measured the flat area between #2 & #3. This is about 21mm and would be less if the bores were larger. You could perhaps compare that with same area on yours


measured to edge of recessed area



67+mm



21mm between chambers 2 & 3

I'm still confused tho as the 875 bore is 68mm and the 998 is 72.5mm. That means the bores would be just a little wider than the bit I've measured (combustion chamber?) but the witness marks from the head-gasket look a lot wider than that and I'd have thought those matched the bores.

I think I better compare this head against an 875 I have

The number is for the casting not the machined finish - the chambers are machined to suit the application and may well have been given a different part number - the 107 was a very early casting and machining could have been for any of the bore sizes they were playing with at the time.

You will also note if comparing a 107 with other heads that the slots for the coolant passages are shorter.

Fantastic Darkspeed and with Jan 67 date quite approp for my car as it was registered in Jan 67

There are sometimes markings on the weights as well, typically it's a number that relates to crankshaft advance in degrees. The weights have a stop on them that can be filed down to increase the total advance, or welded onto to reduce the final advance.
I have messed about with a couple of dizzies for Rover V8's, setting the maximum advance for 20 degrees / 22 degrees so that they work with a static of 16 or 14 degrees for an all in of 36 degrees. As the Vac unit is a starting/economy/emissions device, I strip them off, when engines are tuned / modified from stock the Vac signals are so bad it just creates issues. Most Dizzies for modified engines have no vac, they just have a fixed curve typically 20 -24 degrees crank advance set for a linear increase from 1000 to 3000 rpm on the weights. After 3000/3500 RPM on an N/A engine ignition advance, once optimised, makes little difference.

You have also helped me identify a NOS Vac unit I have - Sport - I expected it would be but as I have no intention of ever using it I have never checked until today.

Amazing. Does it have that same long number (544......) after the 3-10-10 bit?

you could sell that as 'convert you STD Imp dizzy to Sport spec'

Oh wait, we need to see how the springs and weights differ

Well I got my 2nd Sport distributor already

As I said the seller accepted quite a low-ball offer for it and for £31.30 it arrived today

Not sure if I've said already but I was wondering if the cap differs on the Sport ones (as there are caps listed on Ebay for Sports that are quite expensive) but was told on Fb forum all are the same.

I was .'. pleased this one has a cap and will compare it with the one on my STD dizzy. I actually had a look at the numbers on them tonight and they differ but the caps look identical.

Also, as Darkspeed said, the vacuum unit on this later Sport one (41190) is same as the earlier, respite the Lucas chart saying 'none' for vacuum code.

I keep looking at the number on this in case I've read it wrong (41109?) as it wasn't listed for an Imp but it's definitely correct

Anyway I was a bit busy working on the VDP today but I will be getting into the Imp parts soon.

I'm also going to examine the Imp Parts List to see what it shows regarding the dizzies and associated parts. Don't know why I forgot to do this before as I've had the book for years and it is very detailed



as received from Ebay




I now have a cap to refer to/compare



2nd version of Sport distributor. possibly matches to 2nd version of Sport head



same 3-10-10 vacuum unit as earlier 25D (41132)



Lucas part number for cap



41132 LHS. 41190 RHS. will be interesting to see how internals differ

So I set about the cleaning couple of days ago and am very pleased with the way the block came up. Just used a bit of the Green Gunk, an old paintbrush and cloths (for nooks and crannies). On the gasket faces I used Scotchbrite pads. I have 4 different grades (red, gold, green, grey I think) and started with the finest but later used rougher ones and no damage to the alloy.

I started cleaning the (very oily) timing-chain cover also.

I was moaning about the damage done to the crank journals last time (by having them exposed to damp air after 40+ years protected in engine oil and then spraying some curse word useless fluid on them to protect them from damp and making it worse ) but I'm also cleaning them with the pads and they seem ok. The pics are mb a bit forgiving (due to flash) but there's nothing more I can do other than get them re-ground or something and I'm not doing that. Having said all that the bearing shells, well the middle one anyway, are showing signs of corrosion so perhaps the journal(s) weren't as clean as I thought when it was dismantled.

I'm also blaming all the rust-staining on the cylinder bores on myself. When I stripped the engine they were clean and damp storage (I hate Scotland) has caused this. Pretty sure I didn't spray them like the crank and they aren't as rusted. Funny that

The block looks brand new which makes me very happy as this engine has been carted about thru various lock-ups over the years with leaking roofs and break-ins and looked horrific when I took it to the sanctuary of my barn about 6 years ago.

The upper side (block sits inclined to RHS in car) is a bit stained but nothing really bad. If you look at the pics at start of this thread it's some difference. They are all of the upper side of engine which was sitting in leaky lock-ups for years and years.

I've only found a tiny bit damage. One thread for the (for the water pipe-elbow stud) has been mullered with a non-standard bolt. I think it is metric as the Imperial spanner wouldn't go on it and it should be a stud anyway. Will be easy enough to sort as it's not off-centre and there is still some thread below the top of hole.


I've also being trying to do more forensics on the block to prove to myself it is original to the car. I had a go at this a few years back but it was inconclusive dating Imp engine components and have now picked up a few more pointers by reading the parts list and asking on a Facebook group.

To re-cap.... my block has no engine number on it which makes sense as I was told it had a Sport engine fitted before it was registered. The chassis number (419 series) is for a Mk1 Imp DeLuxe so the original original engine would have been a normal 875. I'm basically looking for clues that my bottom-end was made prior to Jan '67.

So what I've found is:

• Sport block would be drilled and tapped (on underside for oil-drain pipe from head
• Sport pistons are a fraction longer than STD (about 0.1mm)
• Sport pistons have a fractionally bigger compression height (about 0.05mm)
• Sport gudgeon-pins were thicker-walled
• the driving-gear and driven-gear for the oil-pump on the Sport were Tutrified and should have a T on them
• there were different drain-plug positions on the sumps which could be used to establish a date

So what have I established on my parts?

• my block definitely has the tapping for the oil-drain but this was also available on very late Imps so it's not conclusive
• it's quite hard to measure to 0.1mm with a vernier but I'd say mine are nearer the STD dimension
• compression height is even harder to measure accurately as there's no way to know your caliper is exactly on centre line of gudgeon-pin bore
• my pins look thick-walled but don't have a thin one to compare with
• can't find a T on driving-gear (on crank). still to check gear on pump
• not got my head round the sump periods yet. need to check parts list further but I definitely don't have the very early type with plug at rear

What I'd really like to do is go back and speak to the guys who had the Imp before me. I did this 30 years ago roughly and it was a mixed success. I'm now worried the guys will have died but it's worth a try I guess. My plan was to go back when the car was finished so I'd have something nice to show them but they will definitely be dead by then

I've said before but I know my Sport head was put on another car back in the 80s as I've spoken to the guy who did it. He fitted an L4 head which is ironically quite similar to the Sport head but for some reason didn't employ the oil-drain. I always wondered where he got a suitable plug to blank-off the hole in block. When I removed it last night and saw an integrated sealing-washer I thought it must be a sump-plug and sure enough taking my own one out of the sump it's identical.



underside of block looking like new



flywheel end



timing-chain end



crankcase area



upper side a bit stained



top face




timing-chain cover very oily



thread on underside of block for oil-drain pipe looks OEM


plug that was in hole in block is identical to my (corroded) sump-plug




crank journals seem to be cleaning up ok




crank bearing shells. 1 scored, 1 with corrosion and one ok



cylinder bores look ugly with damp but hopefully not pitted


something up here


there should be 2 studs/washers/nuts for water-pipe elbow. threads were messed up on the one remaining



looks like there is enough thread left in the damaged one to sort things out



no sign of a T, for Tutrified, on my oil-pump driving-gear