Bench testing a re built Mk1 Hillman Imp engine.

Having rebuilt Imp engines many times I have never then set it up on the bench and test run it, I always placed the motor back in the car and did it that way. Whats involved and what are to pros and cons of doing the bench test?

Number one is just who clean and accessable the engine is. This engine is destined as a display engine and has no actual car to be fitted in, so in this case I have time to spare to work slowly through the test.

The engine is a very very early Mk1 Imp engine and dated 1963, its number is B41/1/501572 WSO the wso means its an export engine and the 1572 means thats the number of engines built to that time.

Test one was to ensure all the oil galleries were filled, once the Shell Oil was in the sump and I had turned the engine over, the oil filter bowl had taken its fill and the sump could be topped up.

Next is to make a jig to offer better support, then do electrical connections, fit a small petrol tank and fire up the motor! Its now 49 years old by the way, it will become 50 years old after the Imps launch date which was May 3rd 1963, this engine will be from that early series.



Roy

Imp transaxle spiders

This subject is probably unknown to many Impers?

Only the very early transaxles had the captive spiders as far as I know, just as well, its impossible To service the seals without taking the large nut off on those boxes, I wonder who thought that idea out?

Note the differences on the corners, the one next to the camera has sharp corners which are best removed if serious hard work or rough roads are expected, as the sharp corners will bite into the rubber drive coupler.

An early Imp drive spider, note the groove at the end of the shaft, the groove held a circlip which stopped the shaft from being removed from the transaxle, only the early Mk1 boxes had this?

The later shafts looked like this and could be removed from the transaxle so that the lip seal could be replaced.

The early shaft with its circlip groove.

Roy

A comment in from an expert is below:

Roy,

I have seen some of the spiders with the the large nut to hold them together.

The spider is also locked into the transaxle by a circlip cut into a groove on the inner spline.

I hope we are not getting confused,over this.

My warning was about the end of the half shaft coming from the rear suspension to the donut.

The end has sharp edges from the way it was forged.

Because it moves in relation to the donut, the sharp edes cut into the donut.

Donuts usually break when the car is accelerating hard, putting a lot of load on the donut, then the donut is also twisted by a lot of compression or droop on the suspension.

The other circumstance is rally stuff, where one wheel is say dropped into a hole and spins, then suddenly finds grip.Then the sequence above kicks in, and the donut shears. The sharp edges will cut and nmake this happen sooner.

So make the end of the drive shaft look like the middle spider and not the one nearest to the camera.

PS Also avoid racing, rallying or anything which might cause exceitement..............life gets so boring.

   

Regards, 

Colin

Colins picture, which was what started the discussion.

You can do this with the shaft still on the car easy enough with a mini grinder and suitable disc, wear the correct eye protection!

Hillman Imp front disc brake kits

They can be fitted on the Singer Chamois, Sunbeam Sport, Stilletto, Commer van and Husky Estate as well. Its a really good move into better braking and of course you will not need to keep re adjusting those front brake shoes anymore.

The kit includes the link plates, stainless steel braided fluid hose and the required spacers, nuts and bolts.

Why bother trying to make these up yourself when a supplier exists in the UK already!

This is another set as fitted to an exported Imp sprint car earlier this year.

A file photo from my suppliers.


Roy

The Imp engine conrod design

When compared with other engine makes, the Hillman Imp has the top of the range design of conrod, the journal end cap is so well located!

This is now 49 years old, bead blasted and washed clean its ready to go again.

The piston is a plus 0.030" size, it took a week soaked in oxalic acid to free off the seized rings and some alloy was lost, it will have been soft from years of water damage anyway?

The rings came out eventually and as far as I can see they are fine to reuse, the dimentions match with a new Rootes Car Co, ring still.

Roy

Roy

How to remove seized piston rings from Hillman Imp pistons

This will apply to most other makes of engines also?

We have a really early Mk1 Imp motor here, the engine number
 is  B / 41 / 1 /501572 WSO (export) which means its engine number 1572 made?

The bores had been fitted with some 0.030" pistons, they were removed when I was gifted the block and parts but all rings were well seized and to remove them risked breakage.

An oil and petrol mix was tried for a week, they were left soaking  and checked daily, nothing very much changed.

I then moved to using Oxalic Acid, its quite mild when mixed to a ratio of a half cup of powder to a litre of water. Daily the rings were tested but lightly, one broken ring will ruin the set.

It took six days before things loosened up enough to attempt to remove the rings that were by now becoming loose. Two second rings are still stuck, I will leave them a while longer, then see what we have and if we can take them out.

Roy

January 1st 2013

The engine was started today and I am pleased to say is a perfect runner, the Solex auto choke carb was a problem, it used too much choke, so we replaced it with a later manual choke Solex carb.

Its starts first time and ticks over around 600rpm and there is no smoke from the exhaust silencer!

Note, some may find sourcing Oxalic powder hard to do, we can post you some easy enough if thats the case?


Note, the rings when fitted back to their pistons and inn the 1963 Mk1 engine worked fine. That engine has now run on about 9 liters of petrol and the engine was run as a demo on May 3rd 2013 to highlight the Imps 50 years since production!

Hillman Imp low compression piston, part two

I have just the one and odd piston, it must have come to me a part of a job lot of parts?
there was no conrod or gudgeon pin but the top two rings were still there, quite worn, so the engine has done some miles.

The piston on the left is the low compression one. Both the skirts are shorter and the top deck is thinner.

The shorter skirt is also shaped and is hollow, check the thinner deck hight on the left piston.

The hight is different due to the shorter skirt, note the gap under the bottom of the skirt on the left piston.

The piston on the left is the low compression one, you can see the valve cut outs are lower and if you look closely you can see a set of half moon marks above the cut outs when the engine was run with the pistons fitted the wrong way around!

Click on the pictures for a closer look.

Roy

The Hillman Imp low compression piston

I have many early pistons from various Imp engines I have stripped but one is different from the rest.

The one on the left has a shorter skirt and the distance from the top deck to the gudgeon pin is shorter. Instead of 18.80mm it is 18.26mm,so 0.54mm shorter, so a lower deck height in the bore and lower compression.

Both pistons are standard bore and both carry the same number inside, 7101025 this tells me they just skimmed the required thickness of the standard piston to get a low compression piston?

This is further prooven when the top lip of each piston is measured, the standard piston is thicker there, 0.153mm to 0.126mm on the lower piston.

This is the lower compression piston, look closely and see that there are half moon marks in the crown of the piston, it was fitted and run the wrong way around!

Roy

Bob Meadows and his Mk2 Imp

A mail to the editor of the Imp Club is below:

Hello Graham,

Did I send you this picture? Its either Wales or Yorkshire?

The registration number looks like a G to me so 1969 and after I came out here, October 1968, so my dad Robert Henry McBride took the picture which was found in some of dads photo stuff.

The guy in the picture is my old friend Bob Meadows, a fellow Camping Club member and also an ex apprentice of Tysons of Dryden St, Liverpool, Bob did brickwork and I did Joinery.

Bob left Tysons and joined Pepsi as a service engineer, he was asked to choose a new model of van for his work, his choice was the Imp Husky and he was very happy with it. His first Imp was a Mk1 green car I seem to remember.

Regards

Roy

Where is Bob now I wonder!

A 1963 Hillman Imp engine rebuild

As this year draws to a close my mind turns to May 3rd 1963 and the launch of what was then a brand new motor car named the Hillman Imp. Seen in the early sixties as a revolutionary car for such times, its engineering still stands out today.

This engine is quite special and said to be very rare?

It has the date it was made printed in white on the steel sump, 7th July 1963, thats just three months after the launch of the Imp on 3rd May 1963.

Note where the inlet valve has just nicked it, the head gasket just misses the corrosion on the left!

There are no piston rings in as yet, I was checking the piston crown height to the top of the block before the rings are fitted. There is bore wear but with a brand new and original set of Rootes standard size piston rings, this motor will be a good runner.

What makes the engine so rare is it has pistons with no valve cut outs, its said that very very few of these engines left the factory?

The crank is in really great condition for 49 years old?

The cylinder head gasket is the last of a batch the Payen in South Africa made for me, they have worked really well and I have never had one leak or blow.

The engine has been a static display but will now be re assembled with its original 875cc pistons, crank and bearings which are all still on the standard sizes. The idea is to have it running on the 50th anniversary of the Imps launch!

Roy

Imp 998cc Wills ring gaskets

There are two types of gaskets when Wills rings are fitted, the actual hollow rings between the cylinder bore and the cylinder head with its groove machined in it and the outer paper gasket that stops water leakage from the block edge.

The rings in front of the blue gasket are the Wills rings, those under the gasket are 998cc piston rings.

Note, Wills rings can not be used on the Imps 875cc liners, they will crush the top alloy casting with the steel liner underneath.

Roy

Erics 1967 Mk 2 Imp

Seen here and after around six years of continual changes, additions and recently a supurb full body repaint is the car that Eric bought off me on one christmas day around 2006.

The Imps rear window is now a closed panel, it really does smarten up the back of the car. I made the template to have tempered glass made to, the frame rubber is made in South Africa.

Roy

Fitting front discs to an Imp and how to remove the caliper pot.

am in the process (slowly) of fitting a set of front disk brakes to my 1967 Singer Chamois.

The parts came as a kit from Colin Valentine, he has supplied two full kits to Hout Bay this year, the other kits

were complete with calipers and discs. In my case I sourced them locally, being Ford Fiesta used calipers and new 240mm diameter

steel discs, which are really low priced here at R280 the pair, about twenty pounds?

This saved a lot on postage, as the small parts kit with mount plates, braided hoses and bolts weigh so much less.

Colin mentioned to check and service the caliper pot by using an airline and place a block of wood across it to stop it flying out, beware your fingers he added!

I tried the air line method but both pots were well stuck and would not move at all, the jig I made used brake fluid and the pots came out with very little problem at all.

Regards

Roy

Phil Webb has an Imp once more!

News from South Africa and taken from the web site named Jolon Imp.

Tonight visited Phil Webb in Krugersdorp to see his 1965 Hillman Imp.

Phil in fact was the one who purchased the Bob Kelsey Imp W103 from Conrad Spamer of the DKW fame and he is hopeful that he can even retrieve the origional Minilite rims rom the Kelsey Imp.

Great chatting with Phil and we hope soon to have a whole fleet of Imps to send me on my way next march.

Terence Tracey standing is with Phil Webb who has found himself another Imp after a very long time!

http://jolonimp.wordpress.com/

 

Roy

Roys Hillman Imp toys

They say the only difference between a man and a boy is the size of their toys?

These Corgi toys are now made by Vanguards, I have a number of those in my display cabinet also but this one is an original Corgi toy, complete with its box!

Check the painting, which we now know was painted by David Shepherd for the Rootes Group.

Roy

Hillman Imp, testing in Kenya meets an Elephant

They were testing in Africa. A chap called David Shepherd was the painter [wiki]. "He was painting trees and elephants when they drove past and kicked dust up on his painting. He got rather pissed off, so they stopped and had a chat with him. The test drivers told him all about the car and he asked if he could do some sketches of the Imp and put it into his painting, which he did. When the painting was finished, it was given or sold to Lord Rootes and it is still in his home estate.

Clark Dawson: "Paul Burch, who had a lot to do with Rootes Development, told this story and got Rosemary, himself and me a copy."

 

The above was a fictional story but it reads well!

 

In 2009 when I first saw this painting, I assumed it was by David Shepherd but could not proove this.
I made a copy for myself, framed it and hung it in my office, where it still is today.

I sent a copy to Impressions magazine, Grahame the Imp Clubs editor published it in the February 2010 issue, page 15. This later brought a reply from another Imp Club member, which was published in Impressions April 2010, page 26, Mike Marsh is the member and he is in Bulgaria.

During this time we had tried to find out if David Shepherd had in fact painted the picture? I found nothing, then Sue, Davids PA found my blog and contacted myself. The mail below tells us more about the picture.

 

From: David Shepherd
Sent: Fri. 14-Sep-2012

[...] You have revived many happy memories I have of the Hillman Imp. I am afraid that the situation which you describe, regarding how my painting came about, is complete fiction, although it makes a wonderful story!
I received a commission from the Rootes Group to paint a painting of the Imp in Africa for their calendar; it certainly made an exciting picture. To achieve this I photographed the Imp at the factory and then added my own material for the elephant and baobab tree. I then painted the painting from the photographs and my existing material.
Since receiving your email, we have been doing some research into who owns the painting now. It would be lovely to know where it has ended up as I have long since lost track of it. Do you have any information as to its whereabouts?
Many thanks for your interest and I hope that I have answered your questions.
Best regards
David Shepherd

 

We are now trying to find the original, we have a signed copy which will be sent to David to see if its good enough for him to allow copies to be made, more on this later!

 

Roy

Your Imp cylinder head needs very thin tappet shims, why?

Hello Impers!

 

A new R 20 Rootes comps camshaft ready to fit, note the closed hole in the tappet cover as this 998cc Imp engine will use an electric fuel pump. This type of camshaft needs timing with a dial gauge, you can not use the method as per the normal or sports Imps.

Some ideas.

 

This often happens because the valves and or seats have been over cut

And the valve has started to disappear into the head too far? New seats and

Valves are the best idea then.

 

You can also cut a bit off the end of the valve stem, so use a thicker shim?

 

With very thin shims you run the risk of the inside of the bucket sitting not

On the shim but the cap it rests in, check this as you will reach a point where

Nothing is changing unless you cut the cap down as well!

 

Roy

An Imp in another view, or how to rig the Imp to turn it 350 degrees.

This was the best way to re build what was to be a sprint car, suitable for fast road it was not an out and out racer but has the ability to go fast when required.

This shot was when I was lowering the car back to the ground, I had had it fully inverted around a month while I worked on the cars underside.

 

For some time I had the car on its side, this really did make a lot of space in the garage!

 

 

Fully inverted, the steel turning rig fits under the car and is well out of the way.

The car as loaded and on its way to Scotland eventually, the turning rig now waits for its next Imp rebuild.

Roy

Hillman Imp cooling fan gaiters

These are now quite a hard to find item, I guess we can use some soft sheet rubber similar to that used on a diving suit but with new ones being made in Australia you may want to buy from there?

The moulded black band is well produced, it looks like a better quality than the original, buy them from Bob Allan of the Imp Club Spares department. spares@theimpclub.co.uk

The red plastic cowl is not supplied.

Roy
 

Hillman Imp drive shafts

This could also be said to be the Singer, Sunbeam and Commer Imps as well.

This is the Imp Sport 1 inch sized drive shaft, the splined shafts are the same and interchangable.
Note that an oil seal fits just behind the bearing.

New bearings and UJs sourced locally and from the UK.

Note the competition drive couplers.

Drive shaft universal joints.

Where they fit.

 

The rear suspension sub assembly is best done on the bench.

 

 

 Later as fitted to the sprint car, working like this has its good side, you can see whats going on and work really clean.

 

Roy