June 22nd 2017
I did another trial at Blagill, Alston (England's highest market town), in which I passengered Neil McHardy and he passengered me in our respective cars. His has a Honda 1500cc engine. The most obvious difference between that engine and the Imp engine is the low-end grunt. When the Imp waves a white flag and coughs to a halt, the Honda carries on chugging up the hill. Strangely the brothers McHardy called their car Struggler, when it doesn't really struggle, compared to mine.
I had the opportunity to compare them one after another on the same Hills.
What I suspected at Blagill was confirmed at the next event with regular passenger, John, at Gale Hall, Melmerby, on the Pennines. The long steep Hills which are mainly just climbs past marker poles did for the little engine. As the momentum slows, if you try to give it a bit more gas the wheels spin, if you try to continue on a steady throttle, the engine just stalls.
If you have the opportunity to get a bit of speed over the ground it seems OK, but if there is a bit of slalom, you lose momentum and can't claw on up the incline. We got a few clears, but so did other people as it was a dry day.
This is a bit of a bugger really.
The Imp engine is a great little motor. For a 1040cc motor it has loads of torque ( with a high torque cam) and runs beautifully. It will crawl up Hills at tickover.
However, things have changed. Cars with bigger motors, electronic engine management, LPG and independent suspension seem to have created a need for more extreme Hills to create clear winners.
Which is bad news for my faithful little Imp engine.
Bigger engine needed.
I went to see Chairman Andrew who showed me his cars and how he used Suzuki engines to get the best out of them. He offered me help and encouragement. I did fit a Suzuki to my Concord, and it was very torquey, but I just can't get the idea of fitting a Rover K series motor out of my mind. They have a bad reputation, connected to early ones, which had head stud problems and suffered over-heating.
Some of this was down to the poor installation in the cars Rover built and partly due to fitters not understanding the cooling system, and how to bleed it.
I found a 1.6 motor and bought that. They weigh 78Kgs which is about 20Kgs more than the Imp engine, but about 30 bhp more.
A quick trial-fitting showed that it would be (just) possible.
The pedal box will need moving (and I will probably convert to cable clutch).
The suspension A-frame leaves no clearance for the oil filter assembly. I'll probably make a new A-frame. That face on the right of the block is where the oil filter fits.
I decided to use the Talbot gearbox from the Imp as it has a Fack intermediate gear which the Imp can't pull, but the bigger motor should be able to make use of when it's wet.
Yes, that is the end of a 7/16th spanner I found inside the bellhousing. I found the rest of it later.
I kept mentioning to John there was a lot of jangling at tickover.
If any previous owner wants it back, just let me know.
Adaptor Plate
I went down the route of making an adaptor plate (using 6mm steel plate) to mate the two.
I did this before fitting the Suzuki engine, but this time it was a bit more complex.
My main concern is that the bellhousing is 260mm wide and the Rover 1.4/1.6 flywheel starter ring is 260mm across. This meant that I had to grind a bit of a rebate into the bellhousing to let it fit.
Other than that the important things like the input shaft length seemed right. there was no spigot bearing in the crankshaft, but an off-the-shelf one, from t'internet, fitted perfectly.
The clutch plate (I used a Talbot one to match the splines) fits into the Rover cover-assembly well and sits on the splines at the right spot. I had to extend the fulcrum pivot bolt for the release arm by 1 cm to get the release bearing to contact the fingers with enough throw left on the release arm to clear the clutch plate.
The Rover installation has the starter motor on the bellhousing, which I am not using, and anyway it would be where my left leg lives when driving. I was confident of being able to put the starter on the side of the engine block, on the driver's side, but it would have to be where the timing sensor is. (Dead centre of this shot)
I decided to remove the timing sensor and rely on a trigger wheel on the crankshaft pulley. This meant I could install the starter tight against the block.
Removing the alloy casting for the sensor was a nightmare. I haven't much experience with alloy, so ended up drilling a row of holes and grinding away the stump. There must be an easier way.
I did think to tape over the crank end before starting.
I want to have the starter on the driver's side as reading about Caterhams, which use this engine (in-line), showed that putting it on the passenger side was a bit of a problem as the exhaust overheats it.
I found that a Fiesta starter motor had the correct clockwise rotation and number of teeth so I found one at the dismantlers at one of our trials sites, Eden Hall.
It needed setting back from the adaptor plate so I had to make some brackets to get the correct position and mesh with the starter-ring.
If you have little left to live for this video may help eek out your remaining, empty hours.
I had to cut an extra hole in the bellhousing as the starter was not in the position that it was on the Imp engine. Such is life.
Some of the bolts connecting the engine and box came through the plate where access was impossible, due to the bellhousing or engine block hiding them, so I welded two captive nuts and a bolt to the plate to make it easier. I also welded a couple of dowels into the plate which locate in holes which I drilled in the block face, to securely locate the plate, so that everything stays where it should be. I only tagged the nuts and bolts. If they should strip in the future it'll be easy to cut them off with a grinder.
Fitted to the engine.
That'll do for the moment.
Next post will be about the thermostat, the engine mounts and the new A-frame.
(and maybe about making the new manifolds - eeek)
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