Cambelt Fail advice

[Deeds]

Hi Guys and Gals

Please be gentle with me as I’m new to posting, I’ve read a lot over the years but not needed to post before.

I’ve done the unthinkable and put off replacing the cambelt when I should have and low and behold BAM it’s snapped.

The issue now is one mechanic says that as it snapped when I was traveling at speed, slowing down from 60 mph to approach a roundabout, this will have caused major engine failure and that at least half if not all the valves will be goosed. He took the cover off and pointed out some of the valves not touching the cam. Now correct me if I’m wrong but the engine in my 1.8 97 Merlot is of the noninterference type and therefore the valves should not have been affected?

The other point that makes me query his diagnosis is that there wasn’t a sudden bang and crash of metal coming from the engine, more a sudden loss of power and the failure to start with a free spinning starter motor, again I may be wrong but my understanding is that some if not all valves would remain partially open thus the lack of major back thrust from them clattering about in the engine and a more sedate coming to a stop.

I’m toying with just getting the belt done as I don’t believe the valves have been damaged, could anyone give me a steer or their own experiences if possible, I’ve been quoted the best part of £900 and as much as I love her, I don’t know if I can spend that on sorting this out. Sorry if this is the wrong place for my post.

Thanks for reading and any advice you may be able to give.

 

Dave

[rhino666]

Hi Dave

Assuming the engine is standard with no drastic skimming of the head, cam changes, etc, it will be non interference and no engine damage will have been done.

Just get the Cambelt and waterpump done and away you go.

A garage will probably charge around £250 to do this including parts.  

 

[Deeds]

Hi Rhino666

 

Thanks for the quick reply and advice. The engine has not been modified or altered as far as I’m aware. The car was owned by a lady doctor before me and a lady who used it to pop to the shops occasionally hence the low mileage so I don’t believe either would have had the engine messed with. I was going to attempt to do it myself in the summer when I had somewhere undercover so I could take my time and do it properly but that’s all gone to pot now. 

Dave

[rhino666]

That is a real nuisance and unfortunate timing, excuse pun.

It is a job that needs forward planning and not one to be rushed into with a tight deadline.

I’ve done four now and for one reason or another the car has been worked on for at least three days; not three solid days but nevertheless out of commission.

Given your situation I would find a good independant garage with knowledge of this job in your area - where are  you by the way, someone may have a suggestion.    

[ast]

Years ago, a mechanic said to me the same thing, after a belt snapped (after only 47k miles) at 70 on the M25. He was utterly convinced, as the AllData book told him it was an interference engine. I said no, just throw a belt on it, and it will fire right up. Didn’t believe me, even after the car was running, claiming “the engine’s different because it’s an import”. Whatever.

And here we go, some forum advice from someone apparently knowledgeable, and quoting from Alldata/AutoData:

Mazda MX5 - cambelt failure=no damage? | Technical matters | Back Room Forum | Honest John

My reference is the trade “bible”, the Autodata timing belt book. They may err on the side of caution but I would have to go with their comments if advising a customer.

They actually say the engine has been identified as an interference type where damage is most likely in the event of belt breakage.

Pro-mechanic, upon being presented with a dozen links stating the engine is non-interference:

OK OK but there are 200,000+ internet search returns for Elvis being alive and 1,000,000+ for the earth being flat.



It’s no big deal but I’ll always go with UK info published by a respected trade source…and always always err on the side of caution where DOHC timing belts are concerned.

Perhaps that is why over some ten years no car I’ve worked on, where the customer has followed my advice, has suffered belt or tensioner failure.

I do appreciate you are trying to offer help.

And even an email from AutoData:

Martin,

Thank you for contacting us and bringing this to our attention. The latest
edition of the Timing Belts book does indeed quote the Mazda MX-5 as being
an interference type engine. However, recent information we have received
from our operations in the USA, where this model is very popular, and
further research in the UK has revealed that it is in fact a freewheeling
type engine. The Mazda workshop manual information is very ambiguous in
this respect and in these cases we always default to quoting “interference”.

We have made a note of this and the next edition of the Timing Belts manual
will reflect this changed information.

Regards

xxxxxx xxxxx
Technical Origination Manager
Autodata Limited"

Is “AutoData” a book actually supplied to mechanics to back up their sucking through teeth, and relieving frightened owners of wads of cash.

That you have been quoted £900 for a cambelt fitting confirms your mechanic is a shyster and fraud. Let me guess, the quote consists of striping the head to check for bent valves, followed by “you’re extremely lucky mate”. Cambelt change should be about £250, but get them to fit a new waterpump and genuine Mazda cambelt gasket at the same time (£100 or so extra). Older waterpumps can start weeping after a new belt being fitted, and its not an obvious leak (no puddles, just loss of coolant).

[Deeds]

Thanks, Saz and Rhino for all the info, I’m based in Marple south Manchester, Cheshire/Derbyshire border.

I’m thinking of trying to do this over a couple of weekends weather dependent. I was thinking of stripping down the front and removing the radiator to make it easier to get at first then tackle the job itself the following weekend, again weather permitting. I’ve tried a couple of mobile mechanics but they don’t seem to have much knowledge of the car or engine so dubious about using anyone who doesn’t know the engine.

I’ve also been looking at swapping out the coolant, it’s currently got some green coloured stuff in so think it may be the genuine FL22, so was looking to get some to do a flush and replacement whilst I have the rad off. I’ve seen it on eBay but also Ravenol do a concentrate for much the same money, around £22 for 5l?

Thanks again to everyone who contributed to this post, I feel much less manic now and want to get on and tackle it and get back on the road where Merly belongs.

Dave

[rhino666]

Good man Dave

It is a right of passage job and will  bond you with your car - well that is the idea anyway

At some point the weather will settle into summer which makes things easier if working outside  - now well overdue. 

There are quite a number of good write ups on this job and a lot of us have done it ourselves.

You will have the right attitude and will clean and replace items that a garage would not get involved with.

Don’t worry about the coolant - drain it and see what it looks like. If it requires replacing just use a good quality antifreeze diluted with deionised water to the correct ratio - 50% from memory.

Ask questions and share any issues - we will do our best to advise.     

[bally3]

the FL 22 coolant is only for mk3 as far as i’m aware 

 

PRODUCT DESCRIPTION

Genuine Mazda Longlife FL-22 Coolant

This coolant is only for Mk3 models designated to take longlife FL22. The easy way to identify this, is to check the radiator cap. If your vehicle is meant to take this coolant it will say “FL22” on the sticker. If it doesn’t say this, then only use the standard coolant. Unlike standard coolant which requires changing every 4 years / 62000 miles, FL22 need only be changed every 11 years or 125000 miles, which ever comes first.