Technical 1999 Pushrod Seicento valve gear noise

[Frenchseicento]

The car has done under 65,000 miles, but has had an intermittent clatter, presumably from the valve gear, since shortly after I bought it in January this year.

I just took off the rocker cover, with the engine cold, and checked each rocker (with opposite valves fully open), and there is no clearance on any of them to account for the noise.

However, I noticed that there is considerable sideways clearance on both numbers 1 and 8 rockers, those at the ends of the shaft. If I move them smartly back and forth along the shaft a fairly loud click is produced as they hit either the end circlip or the rocker pedestal.

All the other rockers have springs to take up any slack, but there is no provision for this on the two at the ends.

I'm now hunting for Belleville washers to put between the pedestal and the thrust washers, or failing that, I'll make up suitable shims.

Has anyone else found this as a reason for valvegear noise?


EDIT: I meant curved or wave spring washers

 

[rallycinq]

Usually its oil related issues with the hydraulic tappets. Around 99 there was a change to ones that you couldn't preload.

I always found them sensitive to oil quality. A good quality 10/40W that is fresh always helped.

Cheers

D

 

[Frenchseicento]

Thanks, I've found that noise from hydraulic tappets is usually cured by an oil change for the other old nails I have had, but this noise is intemittent, possibly depending on engine speed, and is not usually present just after starting the engine.

An oil change made no difference, and as I said above, there is no up and down play whatsoever on the tappets with the engine cold, having stood for several days, ample time for tappets to lose their oil.

However, I have just noticed that there are no thrust washers at the ends of the rocker shaft between the circlips and the adjacent rockers, which may be the reason for the excessive sideways play.

All the diagrams I have been able to find for the 899cc rocker shaft show thrust washers, and I would expect them to be fitted to avoid the rockers rubbing against the sides of the circlips.

It does not appear that the rocker cover has been removed before, as all the hoses which I removed still had the original FIAT retaining clips. Unless the FIAT dealer who serviced the car used or re-used these.

Can anyone confirm that there should be washers between the circlips and the rockers at each end of the shaft?

 

[Frenchseicento]

I shimmed the rockers to reduce the sideways play, and while cleaning up the rocker cover before reassemby I noticed a scuff mark on the pressed steel baffle plate inside the cover, which corresponds to position the lifter end of rocker no.8.

The rocker also has a worn corner where it has been contacting the baffle.

Someone has bent the plate down, just below the oil filler cap, causing it to touch the rocker, possibly by shoving a funnel or similar into the filler hole.

 

[David C]

Someone has bent the plate down, just below the oil filler cap, causing it to touch the rocker, possibly by shoving a funnel or similar into the filler hole.

Ah, good that you found a positive reason for the noise as well as the missing washers.

Has the noise improved now?

My Cinq 899 had the earlier rockers which had both a hydraulic tappet and an adjuster (having both is basically an admission that the hydraulic bit really didn't work...!!).
After several years with it being really tappy, I changed the rocker gear to the non hydraulic setup from a Panda and it is considerably quieter.

 

[Frenchseicento]

I haven't put it back together yet. I decided to replace the thermostat, so waiting for a new one to arrive, and it's too cold in the garage to work right now.

I'll post the results when the car is back together again.

 

[Frenchseicento]

Ah, good that you found a positive reason for the noise as well as the missing washers.

Has the noise improved now?

Finally put it back together today, I decided to replace the thermostat while it was accessible, so had to wait a few days for that.

The engine now purrs like a kitten, the loudest sound is from the injector, no more of that clatter