Is anyone aware of a definitive list of non interference and interference engines across the Fiat range? I'm mainly asking about petrol engines but maybe diesels will help others as well.

Thanks

I'm very rusty on the petrol engine "non interference" candidates. A crude guide is compression ratio. The lower the CR the less likely of interference.

By definition (based on compression ratio) then all diesel engines will be interference (there may be exceptions). However the likes of the later 16V multijet JTD engines have protective camshaft rocker arms. These arms have inbuilt weak/fracture points that are designed to sheer/break if a valve comes into contact with a piston. This is what is supposed to happen but I have no knowledge of if this actually happens with no valve, guide or piston damage.

All the old style 8v fire engines are non interference

Dave's right about 8V engines and I can confirm from experience that 1.6 and 1.8 16V engines are not.

Thanks all.

So my parents have a 2010 (60 registration) 1.4 8v. Is there any need to worry about cam belt change of just let it go? I think (if my memory serves me well) the interval in the handbook is 5 years or 4 for city driving or 120,000 km.

It's not going to do any damage but what happens if it lets rip in the middle of nowhere? These have got to be one of the easiest and cheapest belts to change so I'd do it for peace of mind.

austenw90 said:

Thanks all.

So my parents have a 2010 (60 registration) 1.4 8v. Is there any need to worry about cam belt change of just let it go? I think (if my memory serves me well) the interval in the handbook is 5 years or 4 for city driving or 120,000 km.

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The new engines are all interference as they have the vvt pulley and solenoid


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Always change the cam belt at the specified interval have seen so many engines destroyed by it being overlooked have also seen plenty go early aswell

Avaxbox said:

The new engines are all interference as they have the vvt pulley and solenoid


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Really interesting, as you say even 1.4 8V is VVT since the Punto Evo.
I think the 1.2 8V has no VVT, so no interference ?

Where did you fin these technical informations ? It's always really interesting, if you have a source

Looking at the cars I work on you can see the solenoid into the head

I know the 1.2 8v in the ka has got vvt on it
Autodata lists whether engines are interferance or not
As stated for the cost of a belt change its well worth it for the peice of mind
I remember years ago seeing 1.8 escorts snap the cam in 3 places when the belt broke on start up but do no damage when it broke at 80 mph

how can I know if I have an interference engine or a non interference one ?, I have a Fiat Single point Injection 1.4 Liter 4 Cylinder 8 Valves Engine, Car bought 2004

and how do I know if I have Variable Valve Timing in my engine ?

Mando said:

how can I know if I have an interference engine or a non interference one ?, I have a Fiat Single point Injection 1.4 Liter 4 Cylinder 8 Valves Engine, Car bought 2004

and how do I know if I have Variable Valve Timing in my engine ?

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We have both a 2010 Panda with the 1.2 non vvt 8 valve engine and a 2012 Punto with the 1.4 8valve engine with vvt. So I have also wondered which of this engine family is interference and which is not. (don't know about other fiat engines). As regards the Panda, I'm pretty certain that all the earlier engines (mk1 pandas etc and all 1100's) were non interference? I believe it was when the 1.2 changed from a solid cam sprocket to the VVT that it became interference? So I believe my Panda to be non interference?

Here's a video showing the non VVT sprocket



and here's the VVT jobbie



I'm only referencing these videos for the illustration of the sprocket types - not for their instructional efficacy.

As regards the 1.4 8 valve engine the pulleys look the same and I believe the same situation regarding the VVT engines being interference applies. So, as far as I've been able to find out if it has a "solid" sprocket it's probably non interference. VVT sprocket means it's almost certainly interference. (I'm not going to "experiment" with our Punto just to find out!) As far as I know, On Panda and Punto, these VVT engines started to be used around 2011/2012

So I think it almost certain that a 1.4 8 valve built around 2004 is going to be non interference? - But if someone knows different? On both my boy's Punto and my Panda it's not that easy to get the plastic cover, which encloses the cam sprocket, off. You can also tell if it's VVT by looking for the VVT control solenoid. To find it look at the top of the engine. Find the oil filler cap and to it's left you'll find the cam position sensor Plugged into the top of the cam cover near where the pulley is (a black plastic "widget" with an electric wire connected to it) Early engines didn't have one of these - don't know if your's has but probably it does at that year. Now look between where this sensor is mounted (or not mounted!) to the cam cover behind the sprocket, and the oil filler cap. slightly towards the rear of the cam cover will be the VVT solenoid (if it's a VVT engine) it screws horizontally into the cam cover where it can control the oil flow to the sprocket. It is a metal cylindrical "widget" with an electrical connection plugging into the rear of it. If you've got one of these then your a VVT engine and so interference.

here's what one looks like out of the engine:

https://www.google.com/search?q=fia...-UQ9QEwC3oECAQQDg#imgrc=Ja11gx-aTPgCTM:&vet=1

Strewth, that turned into a bit of a marathon didn't it? All this info is just stuff I've found out for myself and I believe it all to be true but I couldn't guarantee it. There's a lot of more knowledgeable people than me on here who might like to chip in with more info?

My own attitude to cam belts is not to risk running them for too long. Ok, maybe I do have a non interference engine but, If I'm sitting stationary in the fast lane of a busy motorway during rush hour because I didn't change my belt and it broke, the fact it hasn't stuffed the pistons into the valves is going to be of minor interest at that moment!

dear friend thank you for your precious info, and help, yet I still struggle and find it hard to tell and look on the engine, I will try to take some pictures and try to figure out together

Pugglt Auld Jock said:

We have both a 2010 Panda with the 1.2 non vvt 8 valve engine and a 2012 Punto with the 1.4 8valve engine with vvt. So I have also wondered which of this engine family is interference and which is not. (don't know about other fiat engines). As regards the Panda, I'm pretty certain that all the earlier engines (mk1 pandas etc and all 1100's) were non interference? I believe it was when the 1.2 changed from a solid cam sprocket to the VVT that it became interference? So I believe my Panda to be non interference?

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A while back I was looking for similar information for my Grande Punto and found this thread from 2015 where matty23 posted information from Autodata about the interference characteristics of some of Fiat's engines:

https://www.fiatforum.com/panda/357352-interference-non-3.html?p=4106826

If this is correct ... if ... then the Panda 1.2 8v 188A4000 engine (compression ratio 9.8) is an interference one?

As for my car with its 1.2 8v non-vvt 199A4000 engine ... nothings says interference like a first-hand account of a misaligned cambelt causing bent valves:

https://www.fiatforum.com/grande-punto/324075-who-said-valves-couldnt-touch-pistons.html

Hope this doesn't muddy the waters too much!

Pickwick said:

Hope this doesn't muddy the waters too much!

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Thanks very much for this Pickwick. But, Oh deary me! and I thought I'd got on top of this! Hopefully it will never be a bit of information I'll need to rely on as I'm obsessed with never taking chances with timing belts. Strange what confusion there is over this family of engines though isn't it? I can't think of any other like this. Maybe it's simply because it's been in production for so long and undergone so many revisions during it's life?