Technical Problems after Service/Cambelt Change

[jrkitching]

but my other cars that do use 'belts have fairly obvious timing marks on the respective pulleys which would enable an initial inspection and diagnosis if this is indeed the problem. Given the criticality of a timing belt change I would HOPE that whoever did the work would at least get the marks aligned.

Your comment, understandable from anyone not familiar with these engines, illustrates well why so many folks seem to run into problems.

There are no timing marks to align; the cam sprocket isn't keyed, and can be set to any position on the camshaft, so the valve timing is infinitely variable. This does mean you can set the timing precisely to compensate for any small variation in component tolerances, you're not constrained to aligning with the nearest tooth, but it makes the belt changing procedure both non-standard and more involved.

So it makes no sense at all on these engines to talk about the timing being 'one tooth out', since it can be set anywhere. Indeed, if anyone does suggest the timing is a tooth out, it's a sure sign they don't understand the way this engine should be timed.

Even checking requires the correct timing tools, and is practically as much work as changing the belt in the first place, so this isn't something that can be quickly verified.

The Euro5 and later versions are interference engines, so get it substantially wrong and you'll cause some serious damage.

 

[Panda IIs]

Your comment, understandable from anyone not familiar with these engines, illustrates well why so many folks seem to run into problems.

There are no timing marks to align; the cam sprocket isn't keyed, and can be set to any position on the camshaft, so the valve timing is infinitely variable. This does mean you can set the timing precisely to compensate for any small variation in component tolerances, you're not constrained to aligning with the nearest tooth, but it makes the belt changing procedure both non-standard and more involved.

So it makes no sense at all on these engines to talk about the timing being 'one tooth out', since it can be set anywhere. Indeed, if anyone does suggest the timing is a tooth out, it's a sure sign they don't understand the way this engine should be timed.

Even checking requires the correct timing tools, and is practically as much work as changing the belt in the first place, so this isn't something that can be quickly verified.

The Euro5 and later versions are interference engines, so get it substantially wrong and you'll cause some serious damage.

Thanks, that's a really good insight, I think I had read that somewhere else on here but hadn't really digested the implications. Surely the solution at installation is to mark everything up prior to moving anything - oh and use the correct tools!!

 

[murphyv310]

Hi.
Firstly on a 1.2 there is no need to remove the coil pack for a timing belt change. It's had plugs but are they the correct grade or has some ham fisted nut cross threaded them?
Although it's best to use the fitting tools for a cam belt replacement it can be done 100% perfectly if it's done carefully and accurately marked. I've done it twice, firstly on a 2014 then a 2017 with no issues and also no Phonic wheel relearn.
I'd also check for air leaks from the small breather hose and inlet manifold cracks again a possibility from some heavy-handed grease monkey leaning on the manifold.
Plug leads have been mentioned and again a distinct possibility.
Hope you get it sorted.

 

[Popitinpete]

Posts from folks who are having problems with rough running after cambelt changes appear here with depressing regularity.

I don't buy the phonic wheel relearn argument; valve timing is mechanical and unless the relative orientation of the camshaft & crankshaft has changed there's nothing to relearn.

I'd say the most likely cause of these problems is that the engine hasn't been timed correctly after the belt was changed; no amount of software relearning will fix that and it's necessary to get the spanners out.

There's a well-documented official procedure for changing the belt, which, let's just say, isn't exactly standard workshop practice and absolutely needs the proper timing tools. Half the DIY mechanics and independent garages changing belts don't know this procedure, and half of those who do think they know better and do it some other way. From what's been posted here, sometimes these other ways work, and sometimes they don't.

My advice to anyone suffering running issues after a cambelt change is either to buy the proper tools and reset the timing as described in eLearn, or take it somewhere that has the appropriate tools, knowledge, and the will to use both.

This is one of the few instances where I'd actually recommend those without the necessary skills & facilities to take the car to a franchised dealer.

Same

 

[Popitinpete]

Hi.
Firstly on a 1.2 there is no need to remove the coil pack for a timing belt change. It's had plugs but are they the correct grade or has some ham fisted nut cross threaded them?
Although it's best to use the fitting tools for a cam belt replacement it can be done 100% perfectly if it's done carefully and accurately marked. I've done it twice, firstly on a 2014 then a 2017 with no issues and also no Phonic wheel relearn.
I'd also check for air leaks from the small breather hose and inlet manifold cracks again a possibility from some heavy-handed grease monkey leaning on the manifold.
Plug leads have been mentioned and again a distinct possibility.
Hope you get it sorted.

Unless the plug leads chose the exact time between the car going into the workshop and being driven away to break down its highly unlikely. The air leaks from the breather hose and air cleaner assy being leant on make absolute sense.
Facts: car running perfect, has cambelt change now running like a dog. The problem arose after the car was worked on.
Hope the OP gets back to us.

 

[Popitinpete]

Your comment, understandable from anyone not familiar with these engines, illustrates well why so many folks seem to run into problems.

There are no timing marks to align; the cam sprocket isn't keyed, and can be set to any position on the camshaft, so the valve timing is infinitely variable. This does mean you can set the timing precisely to compensate for any small variation in component tolerances, you're not constrained to aligning with the nearest tooth, but it makes the belt changing procedure both non-standard and more involved.

So it makes no sense at all on these engines to talk about the timing being 'one tooth out', since it can be set anywhere. Indeed, if anyone does suggest the timing is a tooth out, it's a sure sign they don't understand the way this engine should be timed.

Even checking requires the correct timing tools, and is practically as much work as changing the belt in the first place, so this isn't something that can be quickly verified.

The Euro5 and later versions are interference engines, so get it substantially wrong and you'll cause some serious damage.

There is talk on this thread of doing the belt change WITHOUT undoing the cam sprocket bolt (the unofficial way but probably the most used way). To get the belt to drop onto the cam sprocket you turn the CRANK sprocket a few degrees by temporarily taking a bolt out of the Crank holding tool then put the Crank back to where it was, ie, being held by the timing tool again. If tippex marks were used on the cam sprocket and these are spot on after turning the engine over twice to check everything still lines up the timing will be correct because the cam sprocket bolt has not been touched/loosened ergo the cam sprocket has not 'free wheeled' on the camshaft itself.
Not the official way I know but I reckon by far the most common.

 

[Pugglt Auld Jock]

Hi.
Firstly on a 1.2 there is no need to remove the coil pack for a timing belt change. It's had plugs but are they the correct grade or has some ham fisted nut cross threaded them?
Although it's best to use the fitting tools for a cam belt replacement it can be done 100% perfectly if it's done carefully and accurately marked. I've done it twice, firstly on a 2014 then a 2017 with no issues and also no Phonic wheel relearn.
I'd also check for air leaks from the small breather hose and inlet manifold cracks again a possibility from some heavy-handed grease monkey leaning on the manifold.
Plug leads have been mentioned and again a distinct possibility.
Hope you get it sorted.

Hello Trevor, hope you had a happy Christmas day. My 2010 Panda 1.2 (60hp) has the coils bolted to the end of the cam cover (opposite end to the sprocket) so if you're wanting to use the cam locking bar then you have to remove the coils. On the other hand, as I'm sure you know, I did both the Panda and Punto's cam belts by the "tippex" method without slackening the cam sprocket bolt and had no problems including not needing to do a Phonic relearn on either vehicle. Because this was the first belt change I'd done on both vehicles I did double check that the timing was correct before I started by using the locking tools and then rechecked on completion to confirm. Now knowing that they are correctly timed I'll be doing their next belts by tippex alone.

Of course I always feel it's necessary to mention that, with these engines having no timing marks, I'd only be doing a belt this way if I knew absolutely for sure that the top sprocket was correctly timed to the cam before laying a spanner on it. I think it's also probably safer to do it the "officially recommended" way, using the locking tools and slackening the cam sprocket bolt, if you're not very confident of your ability. I sometimes think it's all too easy for us, who have spent a goodly part of our lives crawling around, over and inside the guts of motor vehicles, to forget how difficult it is for the less experienced to properly understand all the implications of what they are doing. To this day I still sometimes "get it wrong" but can usually salvage disasters with my life time store of knowledge and the friends I have still working in "the trade".

One considerable advantage of doing this job by the "tippex" method is that you don't need to remove the cam cover or spend time "fiddling about" with the locking tools so saving quite a bit of time and hassle. The cam cover gasket however will often be found to be leaking slightly so requiring to be replaced anyway so you'll sometimes need to take the cover off regardless!

All best wishes to you for the year ahead, even if you don't drive a Fiat anymore! (ha ha)
Kindest regards
Jock

 

[Popitinpete]

Dear Forum Members,

I've been a member and reader for a year or so now, but this is my first post. I'm hoping that some knowledgeable members can offer some advice.

I own a 66 plate Panda Easy 1.2 (my first ever car) which I bought at just under one year old with low mileage. I use it for both short local trips and generally a longer motorway jaunt every month or so - although these longer trips have been less frequent since lockdown. The current mileage is 28K.

The car has been great up to now - no problems at all and drove very nicely. I've looked after it and had it serviced yearly. About four weeks ago I had the car serviced (oil change, new sparkplugs etc.) and also had the cambelt changed as it's now five years old. I went to a local Fiat independent garage which I had used the year previously with no issues and which appeared to have a very good reputation according to online reviews at least.

I picked the car up and drove it about 5 miles home with no problems. The next day after about 20 minutes of driving the car began to bang and shake (I'm assuming this was a misfire) and then lost just about all power - the engine did not rev at all with accelerator input. Is this the ECU putting the car into limp mode? It didn't cut out completely as I could just about crawl along at 2 or 3 mph to get off the main road and park up. I turned the engine off. After a few minute I turned the key again and the car appeared to start fine and did respond to the throttle. I managed to get home which thankfully was only a few minutes away.

The next day I tested the car, but just in the quiet neighbouring streets. It started fine and revved up ok while stationary. After about 10 minutes of driving the engine power cut out again - this time with the engine warning light. I managed to restart and drive it around the corner to my house.

I phone the garage the next day and they came and towed it back. Diagnostics showed that the error codes read as misfires in cylinder 1 and 4. They said that the belt/timing seemed to be ok and that they could not see any other obvious problems. They suggested it's likely to be the coil so I had that changed at a cost of £200.

I went back to collect the car and the misfire/power loss happened again about 100m from the garage. Parked up, restarted and took it back straightway. Misfires in cylinder 1 and 4 errors listed again. They had it for a couple of weeks in the end, but said that they were unable to recreate the faults despite one of the mechanics driving it home in the evenings. Again they said that the cambelt was fitted correctly - I'm assuming that they stripped it down again to check this? - and that the car seemed to be running fine. They said it might have been an ECU issue - but I'm very reluctant to let them start swapping parts without any guarantee it's going to fix the problem. .

In the end I went back and collected it. I've now driven about 10 times over the last couple of weeks. The obvious misfire/loss of power has not returned, however to me it feels that the car is still not right. It's rougher and more uneven at idle and there is a slight but very noticeable constant hesitancy/shake in normal driving. My concern is that the power loss issue will return without warning and I'm reluctant to take it on the long motorway journeys planned for Christmas. I'm also worried that any mis-timing might damage the engine.

I've been reading the cambelt relating posts to try and get some ideas. I'm assuming that the garage would have known if a phonic wheel relearn was required? Is that standard practice when a belt is changed on a panda? If the timing (as they have said) is correct is there anything obvious that could have been damaged or not put back properly which could cause these issues.

I'm thinking of taking it to another garage (possibly a Fiat dealer) for second opinion - it would be great if anyone could offer some pointers before I talk them.

Thanks in advance for any replies.

Hi did you get this sorted, I'm keen to know the outcome, it's great when we not only hear of the problem but how it was solved too.