Distributor end play

[Peter Cripps]

Today I noticed that the distributor on my Fulvia has quite a bit of end play. In other words, if I pull on the rotor, I get about 1.5mm of movement. This seems somewhat excessive to me ... presumably the fix would be to replace the shim that sits just above the drive gear on the distributor shaft?

Only problem I can see with this is that there appears to be a pin holding the gear onto the shaft. My Fiats have a similar arrangement, and sometimes that pin can be a real pain to remove!

Any wise words before I set to with a hammer and punch?

Thanks,

Peter

[Tim Heath]

The pin is a "roll pin". Suggest looking for a hardened nail (ie masonary) of around right diameter and grinding point off. Hopefully someone will advise on acceptable end play as some is bound to be but too much could allow static timing errors.

Tim

[Tim Heath]

Further to my last - the nail is to act as a drift not a relacement for the pin. These roll pins can be sourced at any good fixings supplier if you damage it on removal.

[Peter Cripps]

Tim, thanks.

What I think of as a roll pin is a hollow tube with a slit down the side, probably easier to drift out than the solid tapered pins that I've had so much trouble removing from Marelli distributors on Fiats. And yes, roll pins are available at my local hardware store.

Regarding timing error, that is exactly the issue I'm chasing. I set static timing error with a test light on the points, but it shifts by several degrees when the engine is running. I also see about 10 deg of shift as the engine warms up, I suspect because the distributor shaft gets driven up from the cam gear.

Peter

[Peter Cripps]

Meant to say 'static timing' not 'static timing error'. Of course.

Peter

[Huib]

First note that the gear is not symmetrical. On one side the hole is on a tooth, on the other side it is between teeth.. Remember how it sits relative to the square positioning hole for the rotor. If you remount it the other way around it is not a disaster but you may have interference with the clamps of the cap and nearby engine parts.

Put the gear in an aluminium vice and tap the pin out with a 3mm drive pin. Usually it comes out quite easily. It can be re-used.

The shaft is 12,5mm. You need 1/2" shims. Impossible to get in this country so I use 14mm shim. If someone in the UK or USA can get imperial size shims easily I would like to buy some through him (also the ones for the brakes).

Note that if you take the main shaft out and then the top part with the cams off there should be a ring of 2mm thickness.

I have never found any data on the maximum play. I shim it till it just runs freely using shims of 0,1 mm , 0,3 mm, 0,5 mm and 1,0 mm. If old shims are to be re-used you may have to sand them till completely flat again. Also the bottom of the housing.

If you lift the mounting plate for the points and condenser there is a felt ring in the center. It must be soaked with oil.

[P. de R. Leclercq]

One small point: variations in timing as seen with the timing light (at idle) are often due to a worn timing chain.

I have often been pleased to see a big improvement after replacing the chain.

Paul

[Peter Cripps]

Huib, thanks for your usual detailed reply. I do live in the USA, and should be able to get 1/2" shims without any problem. I would be happy to get some for you ... I was looking at a kit of various thicknesses from McMaster-Carr. If you go to www.mcmastercarr.com and enter 3088A932 into the search box, you'll get to the appropriate catalog page. Let me know what you'd like to get.

Paul, yes, I was wondering about the timing chain. Is there any way to check it for wear without taking it off? I did look at it shortly after I got the car ... seemed OK, no slack, but I'm not sure what I would be looking for. Once the engine has warmed up, timing is quite stable; there's a paint dot at TDC on the flywheel, and it doesn't wobble significantly under the timing light.

Peter

[P. de R. Leclercq]

Apologies Peter, I cannot remember if you have a 1600 or 1300. The 1300 distributor can suffer from wear in the spindle bushes, whilst the 1600 one of course, has ball races.

As for the chain, old Harry used to check them by holding them tight around the sprocket; if you could lift the chain from the teeth more than a "gnat's" then he would condemn the chain. Not so easy to do on the engine but possible - probably better on the inlet wheel. 1600s have a longer chain: two links which was actually a bit much (but you cannot have 1.5!) hence the longer tensioner pad.

Paul

[Huib]

Checking for slack by moving it up and down halfway between the two spocket wheels may lead to false conclusions. Sometimes it is very slack, sometimes it appears there is no slack. It depends on the position of the camshafts. There are always valves pushing against the lobes. If the camshafts are in a position whereby the tops of the sprocketwheels are pushed away from each other the chain appears to have no slack. You have to turn the engine till the inlet is on a closing valve and the outlet on an opening valve. If necessary retract interfering tappet screws. Then test for slack.

If not overly bad, no noise when lifting the throttle and the timing light relatively stable, you should be all right.