Wiring an Alternator

Alternator models with integral diode. (most common) Disconnect the brown lead and the thin black lead from Regulator box, terminals 51and 67 respectively and tape up (these are the old wires from Dynamo) The old wires from the Dynamo (at RHS front) need to be taped up and secured out of the way If your alternator comes with the loom then connect the thicker brown wire to terminal 30 of the regulator box Connect the thin black/Mauve cable to the terminal 51 to join the green wire or use a connector block. If your alternator comes without wires then you will need a … Continue reading Wiring an Alternator

Camshaft timing: Specifications

Version Power Intake open Before t.d.c Intake close After b.d.c. Exhaust open Before t.d.c. Exhaust close After b.d.c. New 500 Until October 1957 13 Hp 19° 50° 50° 19° New 500 October ’57 until March ’58 15 Hp 20° 50° 50° 20° New 500 March ’58 onwards 16,5Hp 9° 70° 50° 19° 500 sport 21 Hp 25° 51° 64° 12° 500 D, 500 SW Giardiniera And Autobianchi 17.5Hp 25° 51° 64° 12° 500 F and 500L 18 Hp 25° 51° 64° 12° 500R 18 Hp 26° 57° 66° 17° Continue reading Camshaft timing: Specifications

Wheels and Tyres for Fiat 500s – An overview

For the whole production of the Fiat 500 saloon from 1957 to 1975 the wheel and tyre size remained the same: 125 x 12inch x 3.5inch (125mm tyre width, 12 inch wheel diameter and 3.5 inch rim inside width) There was as a change in tyre quality from Cross ply to Radial in 1964. Crossply Radial Wheel designs varied across the different model configurations, the most common ones are as below:- The ‘N’ wheel was a pressed steel wheel with a welded cap in the centre, without any aluminium hub caps. The ‘D’ wheel was again a pressed steel wheel with … Continue reading Wheels and Tyres for Fiat 500s – An overview

Hazard Warning light – kit installation

Time to fit: 1.5 hours Hazard warning lights are taken for granted on modern cars but for our little 500’s this was not an option. In these days of increased traffic volumes and speed then some means of visual warning of a breakdown is vital and as our cars are prone to the odd roadside rest then Indicator flashers are a sensible idea. For those of us who like to keep our cars original then having modern accessories is not always acceptable, but something to increase our safety might be deemed a good idea, especially for those members who do … Continue reading Hazard Warning light – kit installation

Replacing a Starter Cable

A. With a standard 500 engine (if you have a 126 engine, please see section B) Remove the end fixing of the inner cable by bending the split pin legs straight and pulling it out. Pliers will be needed. Unless the pin it is perfect, discard it, as it is always best to use a new split pin when re attaching the fixing. Inside the car undo the 2 bolts holding down the Starter and Choke lever assembly. It is often easier to remove the 2 front seats, by holding the forward / back lever up and pushing the seats FORWARD off the … Continue reading Replacing a Starter Cable

Fitting twin-spark ignition

Twin-spark ignition is essentially a means of doing away with the distributor cap and the rotor arm. It should be noted that whilst this is a relatively simple alteration a few points need to be noted to ensure long service. IF using the coil off a 126 (or one specified at 1.5 ohms) then the use of the resistor wire (block) is essential. IF using a twin coil at around 3 ohms then you Don’t need a resistor wire. Very useful videos of the coil theory can be found here: THE CIRCUIT (assuming use of resistor wire) The circuit wiring … Continue reading Fitting twin-spark ignition

Spark Plugs for 500s

There are many spark plug manufactures around and all have different codes for their spark plugs, please see below a list of the most common ones for standard fitment 500 original engine (479cc & 499cc): Original plugs Marelli CW 225 N or Marelli 6N; Champion L7 or Champion L 87 Y Alternatives NGK BP6HS or NGK BPR6HS; Bosch W7BC or Bosch WR7BC; Unipart GSP541 126 650cc engines  Original plugs Marelli CW 8 NP; Champion L81 Y Alternatives NGK BP7HS; Bosch W5BC Continue reading Spark Plugs for 500s

Checking and adjusting the Fan Drive Belt

Check the belt tension. When the belt is correctly tensioned it should be possible to depress the belt 10mm at point ‘C’ (centre between the two pulleys) by applying a 10Kg load. (firm push) If it is more than 10mm the belt could be slipping causing the dynamo or alternator not to work effectively. If it is too tight, that entire extra load is put onto the bearings, which will gradually ruin the bearings. To adjust the tension, proceed as follows: Remove the three 10mm nuts (D). Withdraw the outer pulley half. Note. If the belt has any wear or … Continue reading Checking and adjusting the Fan Drive Belt

Gearbox oil: Which grade to use?

There is always some doubt in what type of oil should be used in a 500, 126 and a126 BIS gearbox. If you are not sure what gearbox you have a simple rule of thumb is, if the gearbox has synchromesh then it’s from a 126 (or 126 BIS) and if it’s a ‘crash box’ then it’s a 500! Model Fiat recommend Equivalent 500 all models TUTELA W 90/M SAE 90 EP 126 all models inc. BIS TUTELA ZC 90 SAE 90 EP means extreme pressure and refers to the additive in the oil. The additive is to stop metal-to-metal … Continue reading Gearbox oil: Which grade to use?

Installing a Fiat 126 engine and gearbox into a Fiat 500

The FIAT 500, last manufactured in 1975, was a superb town car. It was cheap, easy to maintain, mechanically robust and very economical. But the engine, for today’s roads does lack some power and for the last 2 decades 500 owners have been installing the larger 600 or 650cc engine and often the accompanying gearbox from the air cooled 126 cars. The engine train from a 126 it is generally very similar in concept, but differs in number minor details e.g. larger carburettor, different starter motor and often came with an alternator and importantly a synchromesh gearbox. The main advantage … Continue reading Installing a Fiat 126 engine and gearbox into a Fiat 500

Gear linkage adjustment

Sometimes when fitting a replacement gearbox you may find that not all the gears are easily selected OR the car jumps out of a gear. The following is a simple way of adjusting the gearlever to gearbox geometry: Assuming the engine and gearbox are fully fitted and all connection points fully secure particularly those pertaining to the gearbox. e.g. The flexible link between gearbox and gear-lever connecting rods should be tightened with a Little play. Ensuring the thin “springy” washer is in the correct place next to the Collar washer. A little movement is needed on both the bolts. The … Continue reading Gear linkage adjustment

Chassis numbers: Fiat 500 and Giardiniera 1957-1977

Fiat 500 chassis numbers per Manufacturing Year YEAR Model Factory From to Total 1957 New 500 (Normal) Fiat Mirafiori -Turin 000101 28538 28,438 1958 New 500 (Normal, Sport) Fiat Mirafiori -Turin 028539 51383 22,845 1959 New 500 (Sunroof, Sport) Fiat Mirafiori -Turin 051384 117657 66,274 1960 New 500 (Sunroof, Sport) Fiat Mirafiori -Turin 117658 181137 63,480 1960 500 D Fiat Mirafiori -Turin 182001 202091 20,091 1961 500 D Fiat Mirafiori -Turin 202092 288933 86,842 1962 500 D Fiat Mirafiori -Turin 288934 421569 132,636 1963 500 D Fiat Mirafiori -Turin 421570 607204 185,635 1964, 500 D Fiat Mirafiori -Turin 607205 800834 … Continue reading Chassis numbers: Fiat 500 and Giardiniera 1957-1977

Filtering out the noises

When I was assembling my Fiat from its thousands of bits I took great care to include as many of the original parts as I could. This included the air box parts around the fan on the engine. I have a pretend 500 engine using a few important 126 parts but making it look like a 499cc proper engine so I made sure I used the original engine outer parts to make it look right. Little did I know about a design fault lurking within the air filter cover. I knew that the 126 engine part had three clips and … Continue reading Filtering out the noises

Our boot won’t open!

We like our Twin Air 500 a lot, and I mean, a lot. It’s the second we’ve had, with 55,000 miles over 4 years, and our previous Diesel, ordered before the launch, covered over 70,000 miles in 4 years without too many problems (if you exclude a new engine). We drive it every day into London, and it’s subjected to speed humps, parking bumps etc…. But last November we noticed something very strange. The rear window and mirrors didn’t demist, and then the the boot wouldn’t open. A quick google revealed quite a number of owners of cars over 2 years old were … Continue reading Our boot won’t open!

Fiat 500 recall information

Fiat 500 recall information Recently we came across the following information on the AA website regarding recalls on Fiat 500 and associated models, which it has received from the manufacturer and from the Society of Motor Manufacturers and Traders. You can access this here. Of course, if you are the registered keeper of the vehicle in the UK, you should receive notification in the post, or at the time of the next service depending on the nature of the recall etc… but if you are not getting the car serviced anymore, or you have moved and not informed DVLA, then … Continue reading Fiat 500 recall information