Timing Belt

My 2009, 2litre Sports has only covered a genuine 25k and in 2019 I intend driving down to the south of France. I realise the importance of the the timing belt (cam belt) and as the one currently in place is the original belt and 9 years old, should I consider having it replaced. Should the advice prove to have it replaced, would going to a Mazda Main dealer be an expensive option.?Ā  Appreciate the views of those who have travelled this route.

Thanks in advanceā€¦Rick

Hi Snagglepuss

I think you will find that your engine has an internal timing chain which should last the life of the engine.

Have you got muddled up with the alternator belt?

Richard.

Yes, you donā€™t have a cam belt. The belt you can see is the auxiliary belt. This is worth changing and ic not an expensive item/ job.

Yes, probably a very good idea to change the auxiliary belt, idler pulley and tensioner pulley.

The pulleys tend to fatigue over time and make a racket similar to engine failure.Ā 

Thank you rhino666, tfrgreen and coconino for your replies. Iā€™m an ex-Triumph TR6 owner so know little about the engine make-up of the MX5 and presumed the rubberised belt was the cam belt, so excuse my ignorance. Funnily enough I wondered why I couldnā€™t find reference to it in the Haynes manual.Ā 

Ā 

Itā€™s a very common misconception as all MX5 MK1 - MK2.5 cars, 1989 - mid 2005 had the external cambelt, albeit under plastic covers. The MK3(2005 on) auxiliary belt is also a bit of a beast when compared to the earlier cars.

Doing the cambelt on a MK1 - MK2.5 is not that easy, so an expense and hassle you are probablty better off without. Unlike earlier MKs, The MK3 also has an interference engine, so if the internal timing chain were to break, pistons and valves would impact each other.Ā 

I think the TR guys often fit MX5 seats to their cars. I remember the TR6 - there was a 120bhp carb version and the more popular 150bhp one with fuel injection. Very nice car - friends owned and enjoyed them as well as one with a TR5 back in the day. Donā€™t see that many around nowadays down here in Devon.

Just read up on them the carb version was the earlier 111bhp TR250 supplied to the US and Canada.Ā  Ā  Ā  Ā 

Thanks rhino666 I had a 150bhp PI 2.5 with MK1 MX5 seats. They were just slim enough to fit either side of the transmission tunnel. Wonderful car but got too old for all the maintenance.

If you did the maintenance on the TR6 Iā€™m surprised you mistook the aux belt for a timing belt (cambelt) as it drives the alternator (and I presume the water pump on a Mk 3) just as it would have done on the TR.Ā  Timing chains are good for longevity but can get noisy over time and replacing them is expensive compared to a timing belt. In my opinion for what itā€™s worthĀ a timing belt change on a Mk1/2 MX5 is a pretty easy jobĀ as holding the cams in position doesnā€™t need any special tools.

Quite right Dick. I did the maintenance on the TR6 but the only belt was the fan belt which drove the water pump, alternator and fed off the crank.This long serpentine belt is totally new to me. Also you can climb inside the TR6 engine compartment but damned if you can on a Mk3.5 MX5. Thanks anyway. Appreciate the fact you replied.

My car is my daughterā€™s cast off after her fiancĆ©e ran the engine dry and overheated it.Ā  Despite extensive work it continually overheated and lost water as well as having a VVT issue.Ā  I fitted a replacement engine and boy there is little working spaceĀ even on a Mk2.Ā Ā My daughter ended up with a Mk4 and I think Mazda must recruit especially small engineers to put them together!

Itā€™s no great surprise when the Mk3 carĀ  timing belt question onĀ  pops up regularly on this forum, when websites like ā€˜What Carā€™ still show the Mk3 as needing regular timing belt changes.Ā  Ā  Ā Ā 

JS

Some people are just that bit superior to others arenā€™t they ā– ā– ā– ā– ?

Iā€™ve done the cambelt on several cars now but would never call it an easy job. Fancy a trip to South Devon ā– ā– ā– ā–  - Iā€™ll give you Ā£75 to do the belt on my very clean 1997 MK1, all parts supplied.

To any mere mortals thinking of taking on the cambelt job, always replace the waterpump at the same time, read up on the job from several good write-ups that can be found online, expect associated problems like snapped bolts and possibly seal/gasket replacement and most important of all allow for the car to be immobile for up to a week. 

As ā– ā– ā– ā–  says no special tools should be required but a lot of people advise use of a cam locking tool and a crank locking tool. I use a couple of big adjustables to steady the cams and so far have got away with a helper standing on the brake to undo the main crank bolt. Do not touch the main crank bolt if you have an early Eunos with 4 slot pulley and short nose crank - the four smaller bolts will undo allowing the pulley to split and belt to be fitted.     

When I did this job for the first time on an early Eunos a bolt snapped on the thermostat housing and one of the four small bolts on the crank pulley needed drilling out and replacing as previously snapped off. I took my time as winter and forced to do the job because of a failed water pump - it took three days and then very shortly afterwards the radiator let go.        

 

1 Like

 

100% agree. Helped on a tech day when the resident expert was going to show a cambelt change on a Mk2 ā€œItā€™ll be a snapā€ were the famous paraphrased words. Everything that could go wrong went wrong. 5 hours later, the unfortunate club member still had an immobile car.

1 Like

 I never meant to come across that way!

Compared to a Clio, Astra, Vectra, Corsa and Civic itā€™s a dream of a job - obviously broken bolts make it less so!  I also use the adjustable spanner trick as I found none of my various cam locking tools would fit the offside cam because of the limited clearance of the VVT gear.  Iā€™m not sure Ā£75 would cover my petrol to Devon but bring it up to Shropshire and Iā€™ll think about it   


Oh my goodness - you would have to allow for the equivalent of a Ken Dodd performance with everyone locked in for up to 12 hours. Perhaps someone has got away with this in the past but I would definitely want this to be a sham success for the crowd where all the nuts, bolts had been eased before and all seals/gaskets pre-checked too. I hope said expert has since recovered from this experience.


[quote=Merlindriver]

Compared to a Clio, Astra, Vectra, Corsa and Civic itā€™s a dream of a job - obviously broken bolts make it less so! I also use the adjustable spanner trick as I found none of my various cam locking tools would fit the offside cam because of the limited clearance of the VVT gear. Iā€™m not sure Ā£75 would cover my petrol to Devon but bring it up to Shropshire and Iā€™ll think about it

[/quote]


I was joking about paying for someone else to do this job - why would I deny myself the repeated torture. Guess itā€™s a bit like child birth where the time between experiences dulls the pain.
That aside you were not firm in your acceptance of my offer and if I doubled the annual mileage of my MX5 driving to Shropshire and back I would require some commitmentSmile

Come up for a beer and we can discuss terms - and we have some great MX5 roads in Shropshire ??

I went to see Ken Dodd - by the time he got 3/4 through the show I was ready for breakfast!

 

The beauty of the search function

So on a MK3 you donā€™t need to proactively change the timing belt and water pump

Holy thread resurrection Batman!
image

Never mind proactively. It doesnā€™t have a timing belt to change. The Mk3 has a completely different engine compared to the previous models and it features a timing chain, not a cam belt.

JS

1 Like