Disaster!! On a trip from Venus Bay to the Philip Island Historic races in March 2014 (see Phillip Island Historic's ) the noise I had assumed to be either timing chain slap or valve gear wear developed into something far nastier, the tapping became a knocking and the engine oil pressure dropped as the noise increased in volume. At speed on the highway this was not that obvious, but as I slowed down when  approaching the racetrack I knew I was in trouble. Noel and I had both driven our respective cars to the event as invited display cars and I had spent the previous night at Noel's with the intention of attending on both the Saturday and the Sunday. After watching a few hours of the event and catching up with fellow A.L.R. and V.S.C.C. members Russell Meehan, John Lawson and Mike Southgate, we decamped and abandoned the car at my brother Stuart's place at Cape Woolami. Noel drove me back to Venus Bay where I had left my overnight bag and other stuff, and then back home to Melbourne the next morning. I then retrieved my tandem axle car trailer from storage and made the two hour round trip back to Stuart's to pick up the car.

The Aprilia made one more trip that month, this time to a panel beater to have the evidence of a misadventure removed (after forgetting to lock the rear left hand door on an after dark test drive a few months before). After this the car was not to move under it's own power again for another seven months.

I removed the sump and found that one big end bearing had failed and was the source of the noise. On removing the caps from the other rods I found the white metal on these rods was also failing. The early first series rods ran directly on the crank without any white metalling. Later first series engines and all the second series engines used bronze backed bearings as used on the mains of all these engines. White metalling alloy rods is fraught with risk and not recommended as I had obviously discovered, but this was a common repair for the early engines.

My habit with old cars is to try and keep serviceable spares for all the wear prone components of the car. With the Aprilia I managed to achieve this by resurrecting the ex- Clive Beattie 1938 platform chassis (chassis no 39-2424) and rebuilding it to the point that we took it to the 2011 Castlemaine rally as an entered car, although the driving was limited to a few circuits of the local oval. I had used the engine which came with the Stainless Stephen car from England ( apparently rebuilt by the late UK Aprilia guru Harry Manning) after plugging up a hole in the bottom of the water chamber with epoxy. By 2014 this engine had seen a period of service back in the Stainless Stephen car after I removed the replacement engine (4260) to sort out what appeared to be cam chain or valve gear issue. This was a short lived experiment as the water leak problem reappeared again while Ben Courage was driving the car on the 2013 Castlemaine Rally. After the rally Ben and I made two discoveries. The first was that replacing the Bakelite spark plug connectors with brass rods transformed the performance of the car and it now flew!. The car had run very well at lower revs, but the performance at highway speeds had deteriorated. The second discovery was far less cheery, after removing the sump from the hot engine we found water dripping from between the front two cylinders.

After re-bushing the cam chain tensioner and swapping various bits of rocker gear, Noel and I swapped 4260 back into the car which then appeared to behave itself and now had a new lease on life with the brass plug extensions installed. On V.S.C.C rallies early in 2014 the car ran flawlessly although the (apparently) noisy valve gear was a bit annoying. As things transpired the noises were more ominous than we realised.

After the disaster at Philip Island I made one more attempt at rehabilitating the Harry Manning engine and enlisted Noel's help yet again to swap engines. This time we gave up shortly after installing the engine when Noel realised the sump had a lot of water in it, only half an hour after filling the radiator I had repaired the suspect areas with Devcon epoxy, but had also made repairs around the top of the block to badly corroded areas. Close inspection (a few months later after removing the head) revealed I had built the Devcon up too high next to the oil drain to the sump with predictable consequences.

By now I had resolved to bite the bullet and rebuild an engine that would be trouble free and would last indefinitely. Neither of the engines I had used were candidates for what was sure to be an expensive rebuild as both had significant corrosion issues and 4260 had residual accident damage from a massive prang in South Australia in the early 1950's. I was eventually able to source an excellent replacement block from Paul Vellacott who has a sizeable collection of things Aprilia and kindly parted with an engine he had used in his own car but was now very tired.

Aprilia blocks tend to suffer from corrosion both at the top of the block (where they mate with the heads) and around the base of the liners. U.K owners have routinely filled corroded areas with epoxy over the years with great success and replaced the rotted alloy at the base of the centre stud with a new section of machined aluminium. The block that came from Paul was nearly virgin although the bearings were shot and the crank was to require much machining.

The engine rebuild job was entrusted to Tony De Sensi who runs Speedworks in Ringwood. Tony came recommended by Brian Florimel who thought Tony was one of the few engine rebuilders he would trust with something offbeat these days.

Speedworks can do most of the work in-house but the crank grinding and machining the rods were done by associated businesses run by Tony's ex workmates from his time working for Ian Shugg at Crankshaft Rebuilders in Blackburn.

The bronze backed main and big end bearings came from Cavalitto in Torino, as did the pistons, rings and timing chain. The second series rods were cracked tested and found to be OK as was the crankshaft. The engine was then balanced and the bottom end assembled. I reassembled the rest of the engine myself using the head from the Harry Manning engine and a N.O.S copper asbestos gasket from Italy. The rebuild took a bit over three months and cost over $7,000. Roughly $2,000 was spent on parts and the remainder in labour. The evidence so far is that it was money well spent. The quality of the parts from Cavalitto was as usual first class. I resisted the temptation to fit wedge top Fulvia pistons and markedly increase the compressions given my choice to use the alloy rods. I did toy with the idea and did buy a set of N.O.S Fulvia pistons (an eBay special for a couple hundred dollars) but after some consideration opted for the standard units.

The oil pump appeared unworn and the timing chain tensioner was re-bushed. I painted the water chamber of the block with Glyptal paint to keep future corrosion to a minimum and will use Redline Water Wetter in the coolant as this has been found reduce the corrosion in the very similar Lambda engine to negligible amount over a period of several years.

Noel and I installed the new engine in late October 2014, the car ran at least as well as it had with the previous engine and had more power. I also had elected to try the gearbox from the platform chassis which proved to be a thing of joy as you can now drive the car like one fitted with a synchromesh unit if you so desire. You really only need to double declutch if you are changing down at high engine revs. The previous gearbox was very good but this is better.

I have driven the car 3,000 of kilometres on the new engine. Peter Catalano (Thornbury Carburettor Service and a fellow Aprilia owner) had a look at the car and suggested the valve timing was a bit advanced, I adjusted this and the performance was noticeably better. Anne and I recently took the car on a four day jaunt around Victoria's Great Ocean Road region and the car ran beautifully achieving around 10 litres per100km fuel economy. It's probably worth mentioning I was definitely not holding up the modern traffic! The only slight disappointment was the front suspension damping disappearing due to excessive oil loss. I had fitted an oil reservoir as used on later cars and the damping reappeared after a bit of a recharge. The suspension will be the next project.

Five months on the engine coolant is still crystal clear, a testament to the value of the Water Wetter additive, I think Noel has had the same experience over a much longer period. Corrosion has always been the Achilles heel of early Lancia alloy blocks. As mentioned before Lambda owners have found it reduces corrosion to levels that can't be detected after several years of use. After inspecting around a dozen Aprilia blocks with varying levels of corrosion and discussing the issue with people like Ben Courage, I have come to the conclusion that all Aprilia blocks will eventually suffer the same sort of problems that Lambdas were infamous for if the owners don't take sensible precautions. I would recommend Bill Smith's book on Corrosion in Lancia Lambda Engines* to all Aprilia owners. I am far more relaxed about the long term future of the Lambda my father and I own than I was a few years ago. Modern coolant additives designed for pressurised cooling systems are by and large absolutely the wrong thing to use in your Aprilia and may accelerate corrosion.

Andrew Cox

March 2015

Chapter Eight. The Engine Rebuild.

*The book is available from the Australian Lancia Register.

Contact Robert Bienvenu at