Cast your mind back a decade and you'll remember much eulogising from the motoring press regarding a new concept in automobile engineering. It was the Wankel rotary engine and in particlar, the NSU Ro80. That stylish, wedge-shaped luxury saloon that was to become Car of the Year across Europe. So what happened to it?
As recently as spring this year (1977) it was quoted on the price list available to special order only. But the tale of the Ro80 is a sad one. For, while the rest of the world was struggling to make the Wankel rotary engine work for them in the light of forthcoming emissions laws and the unexpected fuel crisis, NSU gained the deserved reputation for an appalling reliability record on their Ro80 engine would often last no longer than twenty odd thousnad mile before a major rebuild was necessary.
Enter HME
But now the good news. Because of this reputation, the likes of you and I can go out and find a second hand Ro890 with a spent engine for very little, probably with no more than twenty thousand on the clock.
Terrific but whats the use of a lame car with engines costing as much again ? Enter HME
Hurley Motor Engineering is a small company based at Coventry that specialise in converting Ro80s to Ford power. They use the 2 litre V4 engines in most cases but are not fitting the 3 litre V6 as well.
But it is the V4 which is of most interest, because they will supply a kit of parts to enable you to fit it yourself, using your own engine, which you may have purloined from a breakers yard or a wrecked car, perhaps.
The V6 is only supplied fitted and with a brand new engine. Some major panel surgery is needed to shoehorn the big lump into place.
“the V4 will fit in the space without major mods” Budget Swap
So. lets have a look at the V4 proposition. The kit of parts contains everything you need except the engine itself, the carburettor and tubular exhaust manifolds. You can get away with using cast iron Ford manifolds but various things must be moved around to make room and it isn't a tidy job. Either Weber 40DCOE twin sidedraught carburettor or the similar Dellorto 40DHLA will be needed and a suitable air filter. It isn't possible to use the original set up because of the low bonnet line.
Any V4 engine will do but the 2000cc is a better set than the best and most reliable. These were fitted to the last of the 2000GT and 2000E Corsairs and some Consuls.
Why the V4? If you look at the Ro80 you'll see that not only is the Wankel engine amazingly short front to back, but it is also mounted very far forward and so only a similarly short engine, like the V4 will fit in the space without major mods. You should be able to pick up a good V4 (without flywheel, starter, alternator and induction system).
Included in the kit is a specially made cast alloy engine/bell housing adaptor plate, a torque converter adaptor brackets, a special pulley to drive the power steering pump, hoses, pipework, belts, a short oil filter to fit in the limited space available and selection of nuts, bolts and fittings. A purpose-made alloy inlet manifold is also included.
“with the aid of a step by step instruction
leaflet the job should take no longer
than a couple of weekends” Installation
As long as you are a reasonably competent do it yourselfer, you should have little trouble installing the engine. No special tools are needed and with the aid of a step by step instruction leaflet the job should take no longer than a couple of weekends.
Having taken out the old engine, a couple of small modifications are done to the NSU bell housing - shortening location dowels and drillling out a couple of steel bushes. The bell housing adaptor plate is then bolted to the Ford engine and a new crankshaft centre bush fitted.
After removing the Ro80 flexy drive plate from its original boss it is then riveted to the new adaptor plate. A few minor mods and the engine can be dropped in using the new brackets provided and the original rubber mounts suitably chopped about. The steering pump and alternator can then be fitted and the toque converter oil feed connected up.
As the distributor comes very closae to the bonnet, 90 degree rubber connectors must be used for the HT leads and it may be necessary to shorten the tops of the sockets or even fit a distributor that has had the body machined down to lower it five eighths of an inch. The latter can be suppled if all else fails.
Luckily the Ro80 has a twin pipe exhaust system and it is quite easy to modifiy this to connect to the two banks on the V4 especially using the optional tubular manifolds.
All that remains is to plumb in the hoses and other pipework, fit and connect the carburettor, modify the dip stick and you're away.
If this sounds a bit more than you are prepared to take on, you can get the job done using a new engine and all new part at an all in price - which still makes a lot of sense for an otherwise sound car.
“you'll find a lot of Ro80s with huge
batteries and a boot full of old plugs” Buying an Ro80
Although this engine conversion will be of great interest to those who already own an Ro80 there will surely be a potential for buying a car with an ailing engine for the sole purpose of doing the swap and ending up with a budget priced luxury car - and make no mistake the Ro80 deserved its 'Car of the Year' tag apart from the engine reliability problem.
So how do you tell when the engine has given up the ghost, or is about to? Well the problem lies with the rotor tip seals which eventually break up often when the car is asked to do a lot of town driving. The plugs soot up misifiring occurs and the resulting contamination affects the rotor tips. Once this happens the rotor housing will rapidly be eroded and low compression results. The first symptons of this are poor starting and an intermittent tinkling noise from the engine. Fitting a hefty battery and new spark plugs is not a cure - but you'll find a lot of Ro80s with huge batteries and a boot full of old plugs.
If you suspect trouble get an NSU dealer to give it a compression test. The minimum acceptable is nine atmospheres. If its down to six its useless.
Eventually the engine will seize and if this happens under power a shear pin breaks and the drive plate nut can unscrew forcing back the clutch into the torque convertor and maybe even the gearbox itself. Removal of the engine will be a hammer and chisel job in these cases. So try and avoid cars with seized engines.
A common fault is a clapped gearbox mainshaft bearing. Don't confuse this with the normal whine that a rotary engine makes. You'll be putting more low down torque through the box so try and make sure its sound to start with.
“the V4 has something the Wankel never had
-- torque!” On the road
All this work is all very well but what does that car feel like with its new and totally different eingine? I tried both a V4 and V6 conversion and the results were interesting.
Nobody would argue that the V4 can compare to the rotary engine on smoothness - the Wankel is like a turbine, whereas the V4 was always considered Fords roughest running engine. This accepted it is certainly no worse and possibly a little smoother in the NSU than it ever was in a Ford. Main noise is induction roar - the Weber air filter does not act as a silencer very efficiently and a marked sucking can be heard on acceleration
But the V4 has something the Wankel never had - torque!
The Ro80 gearbox is semi-automatic. It has a torque converter and a clutch. The latter is operated by a solenoid so that when the gear lever is touched the clutch disengages allowing selection of one of the three forward gears. With the ad of the torque converter the car will pull away in any gear and with the lusty V4 behind it will accelerate quite happily from standstilll in top gear. Throttle response is instant and top speed is in the nineties remember the NSU is a fair bit heavier than the Corsair.
Fuel consumption works out at around 22 mpg with the V4 compared to the 18 mpg with the rotary There is no doubt that the character of the car is chaned but not all to its dertriment - and it does have reliability.
I thought the V6 car less of a success. It certainly had bags of power but it was obvious that the car was not designed with a bit engine in mind. A little more work in the insulation department seems to be needed as there was a little harshness that was out of character with the rest of the car. To be fair no attempt had been made to improve the sound insulation becausse it was felt that this demonstrator should reflect the results of a typical installation and then it was up to the owner.
Handling with this big heavy engine right at the front of the car was surprisingly good. Only a tendency towards throttle steering on tight corners betraying the changed weight distribution.
So if you want a prestige roomy and luxurious car on the cheap you could do a lot worse than find yourself a lame Ro80 and apply the V4 treatment. Over 100 cars have already been converted just using HME kits. Not bad for a Car of the Year.