Technical Tappetty noise between 3-4000RPM (Mk1 1.2 16v)

[thedigger]

Alec, sounds like you and me have exactly the same problem. Don't suppose you've put magnatec in recently?

You'll have to ask a mechanic who knows these engines.

One thought though for the techies - is it possible for the ignition timing to be advanced making the engine knock/pink (preignition noise = pinking0?

Ignition timing is only affected by changing the cam belt isn't it? Mine hasn't been changed, since I've owned the car (and it's possibly never been changed, benefit of non-interference engines!), so I can't see how the ignition timing would have changed unless the belt jumped a tooth? Seems a little unlikely really. I'll try to get a sound clip of it now...

 

[thedigger]

Ok, it's a pretty crappy clip, but you can hear the sound at around 2k revs (it sounds more throaty on the video, it's a tinny, raspy sound in reality)

http://img42.imageshack.us/img42/3658/video0001u.mp4

It's a pretty crap clip (had to do it from the driver seat as i had no-one to rev the engine for me ) , so I'll try another one under the bonnet when I have a mrs to press the accelerator.

Btw, leaving the indicators on probably wasn't the best idea either :devil: tick, tock...

 

[nedge2k]

Ignition timing is only affected by changing the cam belt isn't it?

No, it's controlled by the ECU based on reading from the crank sensor. The ECU can advance/retard the timing as necessary.

 

[nedge2k]

I'm pretty sure my tappety noise is down to using 10w40. I've just got some 5w30 and I'll be sticking that in when I get round to sorting my oil leak! Will update.

 

[beau]

I'm pretty sure my tappety noise is down to using 10w40. I've just got some 5w30 and I'll be sticking that in when I get round to sorting my oil leak! Will update.

do not use that oil in a punto! 10w40 is the right stuff, if its got a noise then something is wrong, dont try and cover it up using the wrong oil you will cause more damage.

 

[dave]

I'm pretty sure my tappety noise is down to using 10w40. I've just got some 5w30 and I'll be sticking that in when I get round to sorting my oil leak! Will update.

the 5w is right but stick to the higher 2nd number, Selenia K 5w40

 

[nedge2k]

do not use that oil in a punto! 10w40 is the right stuff, if its got a noise then something is wrong, dont try and cover it up using the wrong oil you will cause more damage.

No, it's not. I know what I'm doing thanks, I work for an engine specialist.

It got tappety after I started topping it up with 10w40. When I dropped the oil and stuck fresh 10w40 in, at first it was worse. The it went back to the same. 10w40 is too thick, it'll run nicer on 5w30 and there'll be less friction to sap what little power it has.

 

[beau]

well what ever, but i think 140k on the 10w40 proves you lot wrong,

and like iv said, if your engine taps on 10w40 something is wrong, get it sorted, 10w40 will not make it tap.

 

[nedge2k]

Your experience with one car proves me wrong? Maybe you've heard the noise for so long you think it's normal

 

[beau]

Your experience with one car proves me wrong? Maybe you've heard the noise for so long you think it's normal

i look after around 10 fiat 16v engines between me, my best mate and customers, both mk1 and mk2 models, i use 10w40 in them all and none sound tappety or have ever had any problems.

at the end of the day what was said by chrisUK on that link on other thread is SPOT ON.

cold climate- 5w40
warm climate- 10w40

either way, either of those 2 will do no such harm.

 

[DaveMcT]

Nice argument this might help
http://www.autoeducation.com/autoshop101/oil-change.htm

The first number is the viscosity when the oil is cold. 5w = less viscous than 10w.
The second number is the viscosity when the oil is hot. 30w is more runny than 40w.

5w40 will flow better when the engine is cold but will have the same viscosity when hot as 10w40.
10w30 is thicker when cold and thinner when hot so it loses out on both counts.

If the engine noise is oil related 10w30 will make it sound worse than it does on 10w40. That said, brand new oil can run a bit thicker until its settled down so you could kid yourself and in a couple of days be back where you started.

 

[thedigger]

*Bumpy*

Anyone with this problem managed to sort it yet? My MOT is due in a month, so I might take it into the garage. If they can't find what the problem is, I probably won't bother MOTing it and send it to the FIAT garage in the sky (can't see too many people willing to buy a car with a rattly engine)

 

[DaveMcT]

You could try the screwdriver stethoscope test or use a mechanics steth to locate the source if the noise.

 

[thedigger]

Ok, I feel like a prized muppet now :yum:

Took it to the garage, explained where it was rattling, and drove it over their pit. Took them two secs to find out where the problem was - the pipe going into the middle exhaust box was rotten, so I need to replace the entire exhaust system after the cat. £80-odd for the part, but I'm gonna try to get second hand (I'm selling the car afterall). I take it installing a new exhaust on these doesn't need welding (looks like there's just a clamp after the exhaust).

More worryingly, I asked the mechanic about a spot of rust by the sills (where my Mrs tried to pull out of a parking space and got it all wrong)... looks like there's a ****load of rust to cut out, and they'll need to weld a plate.

 

[thedigger]

Ok, a few scraped knuckles and cut fingers later, it's sorted. Went to a local scrappy and got an entire decent-looking cat-back system for £30. The annoying rattle is gone anyway. Not to sharpen up my angle grinder to get rid of the tinworm.

 

[nedge2k]

I left the noise until it got worse toward the end of last summer - when I found it was actually the cam belt tensioner! Thankfully though, cam belt is a piece of cake on this engine - with the tools.

Can a mod add this to my first post as I can't edit it anymore!