Timing chain / cam removal

[DavidLaver]

The oil strainer I know about - but whats that bit at the bottom with the blanking plate?   

David

[DavidLaver]

...and some more pictures...

[ColinMarr]

The bit projecting forward with the blanking-off plate is the tube that carries a push-rod to actuate the mechanical fuel pump, and the blanking-off plate shows where the pump would have been. It projects forward like this to clear the radiator so as to be accessible from the front after lifting off the grill, whenever it might need attention. It is little things like this that show what a clever thing the Aprilia engine is!

It was quite common to fit an SU type electric pump so I guess this must have been done here. The original pumps were fine and not dissimilar to those fitted to Fulvias.

And just behind this you can see the alloy fitting that connects to the very short radiator bottom hose, which doesn’t look to be too badly corroded. Another nice thing about the Aprilia arrangement is that because the radiator is carried on the engine mounts (also visible in your photo) there is no need for much flexibility in the hoses and they can be very short.

Colin

[DavidLaver]

I've got an Augusta radiator for the car but its tempting to put an Aprilia one in if only to have the dynamo in the middle which makes me giggle every time...  Would also let me use standard hoses, and the standard pump.

If the dynamo is not Aprilia, but still has to run backwards I've got something ex-Fiat 850.  If it runs forwads I'll either buy an "off the shelf" Lucas or recondition one of the Aurelia spares.

Any tips on the oil strainer?   Do they reeeaaaalllllyyyy work...   Did ANY other cars have them?   For the "Bazzered" engine its already got a Fulvia pump and the plan was a remote filter as I did for the Austin 7. 

For this particular engine I think changing the oil every time its run should be enough 

David

[ColinMarr]

David,

If the engine is for normal use I think the strainer will be fine. In ancient times we used to do about 10,000 miles a year and changed the oil every 3,000 or so. Duckhams 20/50 was favoured and cheap. At the same time the strainer was duly cleaner and gunge drained from the brass plug below the strainer, but I can’t recall much muck being collected in this way.

This reminds me of another thing. On the other side of the engine by the distributor is a large brass plug with screw-driver slot. Undo this to release a spring that holds down the oil pressure relief valve. I am not sure it made much difference to the oil pressure, but every so often it seemed normal practice to remove the spring and stretch it a bit. Then to lift out the ball with a magnet, clean it and refit it, tapping it down with a brass rod to re-seat it before re-fitting the spring and plug.

Colin

[DavidLaver]

How is the strainer cleaned?  Other than "every time you depress the clutch".   It reminds me of town gas literally being scrubbed with brushes and water.  Guess in time scratching a sound from a plastic disk at 45rpm will seem as silly.

I love the Aprilia end to end - other than being a bit annoyed at it having BOTH a rear leaf AND torsion bars.  A bit off topic - but anyone know the excuse for that?

David

[ColinMarr]

David

The mechanism is on a ratchet – every time you hit the clutch the vanes rotate a bit and comb out crud, which is supposed to collect against the edge-stop - and this is what you are supposed to clean out at every oil change. That in this day and age you rarely see any crud doesn’t mean much – how many times do you flatten out the paper cartridge filters in your modern car to see if it has managed to catch anything? Remember this is designed to cope with 1930s oil and garage cleanliness! Have faith – it will work.

You must be joking to question the read-end! Not an excuse – a delight! This is one of the real genius points in the Aprilia design. The whole thing about the transverse leaf spring is that it is soft and ‘slow’, and designed only to hold the car in a stable horizontal mode so that up or down deflection can be taken by the short torsion bars, which in the neutral mode are unstrained. In this way the torsion bars return the rear end back to ‘flat’ in the most effective way possible. As far as I know other torsion bar systems are strained one way or the other all the time.

I have experienced a number of cars with independent rear suspension, but none provide that delightful sure footed pitter-pattering over the undulations that I remember so vividly from an Aprilia saloon. Yes, I must get another one!

Colin     

[ncundy]

If it is a wet liner assembly, then you can put a brace across the top of liner (a piece of bar with a hole at either end that locates acros two of the head studs). Of course you can only remove downwards, but the liners will stay put.

[Scarpia]

as I am confined to weekend "forum" visits i'm just catching up on this.(Thanks David for so much input and useful photos, really excellent material for reference purposes.)

just to come back to the fuel pump blanking plate questions which Colin answered , I include a couple of photos of mine .You can see clearly the pump on the arm which is operated by a pushrod assembly.Originally there was a combined pump and "filter king" type assembly with glass bowl on the aprilia.If this design performed a pressure regulation (such as is the case with the modern filter kings) I don't know but the filter was missing on my car in any case due to the modification for dual fuel lines for the twin carbs.
I'm just experimenting with a modern in line fuel injection filter as you can see.This type is cheap, last a long time as this is considerably more effective than the filter king type. (injection systems are much more sensitive to dirt in the system and the capture capacity of this is much more effective.).
agreed it doesn't look so vintage but its invisible in practice and performance comes before originality in mechanical areas. 

[Scarpia]

I can only agree with Colin's sentiments about the rear supension.Its the cleverest and most elegant solution I have yet to see from an aesthetic and engineering standpoint.
The other side of the coin is like much of the aprilia it can be a little fragile.They are like swiss watches, things of great complexity and beauty but don't drop them..

Without splitting hairs though Colin, I'm not sure what you mean about the torsion bars being unstrained in the neutral position.? With the wheels off the ground perhaps?.
The achilles heel of the aprilia are the same torsion bars.They are splined at the ends and tend to wear where they engage in the trailing arms linked to the hubs.Once they wear to a certain point the splines slip (under the torsional strain that is created by the leaf spring) and that side rear corner of the car springs up 5-10 cm. Improves cornering still further on one side....Actually a common problem on aprilias. (when they were commonly on the road I mean!)

If the torsion bars were unstrained this could not happen I think.

[ColinMarr]

I guess age is taking its toll – on me as well as Aprilias! I am remembering a time when Aprilas were less than 30 years old, not the 70 they are now.

I don’t recall ever having problems with slipping splines, and if that happens I guess it’s dire and they will no longer be ‘neutral’ for very long. As I remember it, the routine was to level up the car with a second jack under the hub, slacken the torsion bar clamps and withdraw the bar (isn’t there a threaded centre to put a screw in the grip it with?). And then, clever, clever thing that it is, the torsion bars have a different number of splines on each end, in effect a vernier – so that refitting is a matter of offering it up and rotating it until you get an easy unstrained fit – then bolting it all up again.

The weakness was surely in the cable-ends that locate the transverse spring to the trailing arm. They can look OK, but rust from the inside, fray and then give way. This happened to me once in France fully laden on a camping holiday. The leaf spring dug in the road and ripped itself to pieces and the car sank into the wheel arches. I just happened to have a spare cable-end with me…. took the wings off …. limped it to the next village  and with the help of an agricultural workshop, we got it fixed… and then drove on to Rome.

Colin

[ColinMarr]

And this was a time when you could park you car in St Peter’s Square without any fuss or bother!

Colin

[JohnMillham]

My (second series) Aprilia had its torsion bars welded in place by a previous owner. This wouldn't have been too bad if they had first been in the appropriate (level) splines, but they had one up and one down, resulting in  a permanent "lean to the right". I could go round roundabouts at a ridiculous speed, but had to slow down rather more than usual in order to exit left! It would have been a great car for Silverstone or Goodwood, where most of the corners are right handed.

[Scarpia]

mine too.!! only when I stripped it down did I realise it had been welded in place.

I had to undo the leaf spring (sharp intake of breath), grind the weld off the end of the torsion bar, and then carefully align both sides and re weld.Replacement shafts (in better condition) are none existent, and until now its never given a problem again.Actually I cannot remember if it was mainly the shaft that was worn or the housing it fits into but I suppose one day I'll have to re engineer a new shaft /solution. I try not to think about it...

Colin,

are those marks on the photo or do I see two holes in a diagonal slanting line on the side of your engine bay. I have two like that on my car (other side) and I believe they were for mounting a radio antenna?

[ColinMarr]

Scarpia,

I hadn’t thought about welding them in, but I guess that is a solution of last resort.

Yes, the marks are (or were!) the remains of a radio aerial mounting. They pre-dated my ownership of the car and I never did fit a radio. Even in the 1960s I couldn’t be tempted by a 6V valve radio with the bulky power-pack needed to run it.  If you are interested, I know a lovely man who is an expert on historic radio equipment, who also happens to be an Aprilia owner and guru – he doesn’t use this forum and it’s not fair to mention his name. If you are interested I can put you in touch and who knows, he might be able to supply you with a period set.

Colin