Been talking to various people ....

November 5th 2017

... and it looks like a few think my choice of a Rover K series is not an obvious one.

So I thought I may expound my thinking and reasoning.

To start with I've had three cars, two with Imp 1040cc engines, which I think are great. However they just haven't got the grunt to chug up a long hill without politely coughing and giving up.

The first car, I put a 1.6 Suzuki G series 8 valve engine in. I made an adaptor plate and fitted it to the Chrysler gearbox already in place.

It made a great difference. There were a few compromises that I didn't really like, the main one being the inlet manifold, which on that engine is part and parcel of the cooling system. LPG would have overcome the awkward carb location.

The other compromise being the distributor standing to attention on top of the engine. Electronic ignition would have solved that.

The next car had the popular Triumph Acclaim engine and gearbox fitted. It was a good car but I couldn't get to terms with the rather inelegant solution of having a locked diff in the gearbox at the front of the car and a free diff in the back axle. It may have given a huge range of forward gearing, but reverse was the world's crawliest crawler gear.

With the third car, the CAP I decided the Imp engine would have to go. Again it was a great engine and apparently had a successful career when most cars were smaller-engined and independent suspension was rare. But these days the long hauls up long and steep slopes with slaloms was proving beyond the engine, and certainly beyond my meagre talent.

Again, I looked at a Suzuki engine. The M Series 1.6 motors are better than the G series from the point of view of having a simpler inlet manifold and they already use electronic ignition.

But I had a fancy to try a Rover K series motor.

Yes, they have a reputation for giving trouble with overheating and failing head gaskets. But I decided to research the problems thoroughly.

To begin with, this engine is used in Westfields and Lotus without problem. Why is that?

The problem began when Rover decided to try to get it to warm up quickly they put the thermostat in the return from the radiator.

This created two problems.

1st, it was very difficult to bleed air from the system. Although they provided bleeding points on the engine, many fitters did not even know these existed.

2nd. They initially used a lot of plastic in the engine build. Some head locating dowels were plastic.

Also they made a poor head gasket system which relied on bonded-on sealers to make the seals.

So the engine could overheat straight away due to air-locks in the cooling system. When the hot engine eventually got the thermostat, sitting down the side of the block with only a minor hot water feed to trigger it, to open a slug of overcooled water from the radiator rushed into the engine and created a thermal shock which could compromise the head/block joint.

Add in the fact that the inlet manifold was plastic and wasn't torqued on as tightly as a metal one would be, water leaks from the inlet manifold could exacerbate the problem.

Other things like a very narrow fire-ring around the liner tops meant that some slight warping or movement (plastic head-locating dowels remember) could lead to loss of compression.

A new head gasket consisting of 5 layers was introduced. In the centre is a steel shim with swaged on fire rings This, like the original gasket is encased by two steel layers - rather like a sandwich. However, in contrast to the older gasket design, rather than using bonded-on 'elastomeric' butyl rings to contain the coolant jacket and oil drain spaces, the gasket has an additional two steel layers on either side of the gasket with swaged / raised areas to provide the coolant/oil void sealing. These layers are there to help prevent any coolant leakage failures - which, on the older gasket design, was frequently due to peel-away of the butyl rings.

Just as relevant was that in most sportscar installations they either did not use a thermostat or fitted a remote one in the top hose. Not utilising a thermostat is not always a good idea, but it seemed to work.

For my engine swap I decided to take the valve body off the thermostat, but leave the plate in position. This should maintain some back pressure to encourage scavenging of hot water from pockets in the head (through the hot water bleed pipe on the inlet manifold), maybe.

In a trials car which rarely gets above 15mph the cooling of hot water through the radiator hardly occurs until the electric fan cuts in. By fitting a thermostatic switch in the top hose you can easily gauge the temperature of water leaving the head and regulate the cooling very accurately by controlling the fan.

So it has shown. The car reaches 80 degrees quickly and hovers between 80 and 90 all day.

To my mind this is the major consideration in using this engine. If you can adequately provide cooling on a late model engine (which has the later, metal, head-dowels and head gasket) you can concentrate on the benefits of the design.

Power

Although I elected not to install the injection and just use a single ISO (SU lookey-likey) there is still bags of power. The motor is rated at 109 Ps at 6000 rpm and 138 Nm at 4500rpm.

OK, that torque is at quite high revs, but there is still plenty low-down. Even if the power is down a touch as a result of the single carb, there is still plenty of it.

The Suzuki is variously rated depending on the car it is in, but generally about 101 Ps at 6000 rpm with 143Nm at 4000 rpm so the Rover seems slightly peakier.

The Honda (Acclaim) engine (1335cc) by comparison has about 72 Ps and 108 Nm.

Weight

Various people have suggested the Rover engine is heavy. Well yes, it is heavier than the Imp Motor which weighs a featherweight 77Kg.

But it weighs 100 Kgs, which is obviously 23 Kgs more, or about a third heavier.

However it does knock out about 40 more Ps (35 if you are being pessimistic) than the Imp. and the extra weight of the engine is only a percentage of the car-and-crew weight whereas the extra power is a total gain.

The Suzuki engine weighs a touch less than the Rover at about 93 Kgs, but there isn't very much in it.

The Honda 1335cc engine ( I use this to compare as a lot of live-axle cars use this, and I had one myself) weighs about 93 Kgs.

But here is a thing.

To use the Acclaim (Honda) engine most people use the Honda gearbox and final drive (locked) driving a higher geared back axle with a free diff.

That means that:

A) you are carrying an extra diff around.

B) the weight is further forward in the car.

See these two pics.

The yellow highlight shows the gearbox and diff tight behind the Acclaim engine.

Here the gearbox (without a diff) lies further back in the in-line transmission car

So, using a combined engine/transmission unit would seem to put more weight further forwards (even if it is a touch lighter) than the bigger Rover engine.

Anyway, logic aside, the Rover is in the car now and seems to run very well.

If anyone is pondering using one I would encourage them to do so. The 1.4 engine is identical in size and weight to the 1.6, so the 1.6 would seem to be the one to choose.

They are available for £150 or so.

There are still plenty of them about and lots of new spare parts available as well.