MX5 Cambelt

Archives of Posts to the NZ MX5 List back in 2003
Locked
Stephen May

MX5 Cambelt

Post by Stephen May » Sun Feb 01, 2004 1:31 pm

Hey, I have a 138,000km mx5 with no cambelt replacement sticker under the
hood. I assume the worst, it hasn't been replaced. I want to know if the mx5
motor is a contact motor or not (where the valves make contact with piston
heads if the cambelt snaps). Just to know how urgently i should get it
done...

Anybody know, or know where i can find out?

Rex Johnston

MX5 Cambelt

Post by Rex Johnston » Tue Feb 03, 2004 7:02 pm

On Sun, 2004-02-01 at 13:31, Stephen May wrote:
Hey, I have a 138,000km mx5 with no cambelt replacement sticker under the
hood. I assume the worst, it hasn't been replaced. I want to know if the mx5
motor is a contact motor or not (where the valves make contact with piston
heads if the cambelt snaps). Just to know how urgently i should get it
done...

Anybody know, or know where i can find out?
The B series motors ARE interference motors. Replace that belt ASAP.

Cheers, Rex

mx5mike
Need, more, 5-ing, time....
Need, more, 5-ing, time....
Posts: 106
Joined: Sat May 06, 2006 12:06 am
Location: North Shore

MX5 Cambelt

Post by mx5mike » Tue Feb 03, 2004 7:16 pm

Errr, no they are not interference motors. You have been misinformed
somewhere along the line.

I personally wouldn't change it until something like the water pump needs
changing. Of all the cam belt failures I have worked on, all were failures
of a replacement belt. These could have been down to poor parts, incorrect
fitting and tensioning or just bad luck.

If it breaks the worst that will happen is that you are stranded somewhere.

If you change the belt, make sure you do the water pump at the same time
while you are in there as they don't like being disturbed once they have
plenty of miles on them.

Mike.

Janet & Jeff Curtin

MX5 Cambelt

Post by Janet & Jeff Curtin » Tue Feb 03, 2004 7:23 pm

'Ive heard of them being an interference motor ??, Every mx5 book, article,
post I've read says the oppisite!!

Jill Meyer

MX5 Cambelt

Post by Jill Meyer » Tue Feb 03, 2004 7:29 pm

Hi everyone

I own an MX5 which has done 94000kms and have just changed the cambelt
and idlers. The wear and tear on the old one was not significant but as
I work for a motor company who advises between 90-100000kms, thought it
would be a good idea. Much better to be safe than sorry.

As a matter of course with imports it is always prudent to change the
cambelt if the vehicle is purchased with higher kms, as often the
history is not 100%.

Thanks

Jill Meyer
Taikorea Road
RD 3
Palmerston North
New Zealand
Mobile: +64-29-200-5457

Rex Johnston

MX5 Cambelt

Post by Rex Johnston » Tue Feb 03, 2004 7:30 pm

On Tue, 2004-02-03 at 19:16, Mike Saint wrote:
Errr, no they are not interference motors. You have been misinformed
somewhere along the line.
If you say so. Having taken a B6 turbo engine apart (i.e. lower
compression ratio), i'd say that it was an interference engine.
Oh well. YMMV

Cheers, Rex

Ross Bryon

MX5 Cambelt

Post by Ross Bryon » Tue Feb 03, 2004 7:37 pm

When I bought my '91 (at about 134,000k), the seller assured me that
the cam belt had been done at around 100,000k. But, hey, I'm just not
that trusting, so I asked my mechanic what it would take to check it
out while he was doing a regular service...

Not a big deal... "20 minutes in... 20 minutes out", he said. So for
less than an hour's labour I found out that the guy who sold me my
Roadster was true blue. Belt was fine - I'll change it again at
175,000k.

But I am a whole lot happier now that I KNOW!

Ross Bryon
BRG V-Spec 1991 Roadster

On 1/02/2004, at 1:31 PM, Stephen May wrote:

[...]

MX5PWR
Need, more, 5-ing, time....
Need, more, 5-ing, time....
Posts: 127
Joined: Mon May 08, 2006 6:32 pm
Location: Auckland

MX5 Cambelt

Post by MX5PWR » Tue Feb 03, 2004 8:11 pm

Take my advice and get it changed. Mileage is only one part of the equation.
Age also causes the belt to deteriorate. I had a 90 that had 130k on it and
I kept on putting it off, guess what, it went at a most inconvenient time.
The $150 towing fee would have gone a long way to paying for the labour if I
had got it done first.
The engine is not a contact engine but come to a grinding halt on the open
road at 100kph and it may be the car behind you that makes the contact!!!. I
was lucky as it went at about 60kph under no strain. I wouldn't want it to
break at high speed or under load.

The old saying ''Prevention is better than cure' Would you want the
embarrassment of the belt giving way on a club outing !!!

I learnt the hard way - Nigel

zorruno
Black is the new black.
Black is the new black.
Posts: 600
Joined: Thu Apr 13, 2006 11:20 pm
Location: An Eastern Beach

MX5 Cambelt

Post by zorruno » Tue Feb 03, 2004 9:11 pm

they are all non-interference engines. Worst case is that you will be
stranded - I have an AA card and a mobile phone...


Refer to Randy Stocker's pages

Mazda engine comparison:
http://members.aol.com/solomiata/MX5Engine.html

some 94-96 pistons:
http://members.aol.com/solomiata2/94-96 ... ompare.jpg

1999-2001:
http://members.aol.com/solomiata/2001pistoncompare.jpg

cheers
zorruno
(z)

Bryce Pearce

MX5 Cambelt

Post by Bryce Pearce » Tue Feb 03, 2004 9:52 pm

And the day it does decide to break it will be perfectly fine, 25 deg and
you'll be in the middle of nowhere.
My suggestion - Carry out all recomended maintenence and worry about other
things - like where was that dairy that sold real ice-cream...

zorruno
Black is the new black.
Black is the new black.
Posts: 600
Joined: Thu Apr 13, 2006 11:20 pm
Location: An Eastern Beach

MX5 Cambelt

Post by zorruno » Tue Feb 03, 2004 11:21 pm

I wasn't suggesting now to do preventative maintenance, but my (not very
well made) point was, don't stress that you have to get your cam belt
changed at 100,000.0000kms and your oil changed at 20,000.000000000 kms etc
etc

Your car's engine can't talk to the odometer, just get the maintenance done
'around' the time it is recommended, and maybe combine it with a few other
tasks to save labour costs like an oil change, radiator flush, trans fluid
etc.

Too many people stress that their car will blow up if they don't drive up
the mechanic's driveway at 99,999kms. There are many stories of cars with
150,000 km or more cam belts, and some who never made it to 100,000kms
without a cam belt breakage.

incidentally if anyone is interested in seeing a 'Mazda Recommended'
service/maintenance checksheet, I've put one here. It is in miles though.
http://www.mx5club.org.nz/downloads/maz ... ksheet.pdf
Some of these I do more often, some less.

cheers
zorruno

PS: mmm, ice cream...
PPS: and ok, yes Karl, the mechanic's driveway has to be 1km long... ;)
(z)

Lou Girardin

MX5 Cambelt

Post by Lou Girardin » Wed Feb 04, 2004 6:51 am

It all depends on each engine. If the belt has had oil on it it'll break
sooner, etc. But an extra 5,000 km's isn't critical. There is no doubt that
proper maintenance will make your car last. Mine did 200,000km's with very
few repairs.
A cam belt change is so easy, there's no point in putting it off. I don't
subscribe to the 'change waterpump, oil seal while your in there' school of
thought though. Unless they show signs of wear I leave them. Then again I do
my own maintenance.
Lou

Martin Taylor

MX5 Cambelt

Post by Martin Taylor » Wed Feb 04, 2004 8:23 am

On 3 Feb 2004 at 6:23, Janet & Jeff Curtin wrote:
'Ive heard of them being an interference motor ??, Every mx5 book, article,
post I've read says the oppisite!!

Some correspondence I had ...

"
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

Peter Cook
Technical Origination Manager
Autodata Limited

Locked

Return to “2003”

Who is online

Users browsing this forum: No registered users and 5 guests