[clix]

Q: Does the Mk3 have a timing chain or a timing belt?

A: The Mk3 (NC) has a timing chain, helping to extend the service intervals to 12,500 miles or 1 year whichever is sooner.

 

[CaptainHaddock]

Q: Should the timing chain be replaced at a specific interval? I haven't seen it mentioned in any service guide.

 

[clix]

Q: Should the timing chain be replaced at a specific interval? I haven't seen it mentioned in any service guide.

Me neither.
I did some research the Ford Duratec engine and the best I could find is: "No change interval specified."
I don't think anyone's had one long enough to find out.

 

[Mark]

Dragonsoup on mx5.com has done over 100,000 miles in her Mark 3 so she may be a person to ask whether she has had her chain changed yet

 

[safaristu]

It's simply adjusted as chains can stretch
Would suggest 100,000 mile replacement same as any other chain driven car but it could go forever.

 

[Jot]

At least in event of failure it won't interfere with the engine.... phew :thumbsup:

 

[Mark]

At least in event of failure it won't interfere with the engine.... phew :thumbsup:

Jot - Is that true of the Mark 3 /3.5 engines (I know the Mark 1 and Mark 2 engines with timing belts, as opposed to chains, are non interference) - not disagreeing, just questioning

 

[Jot]

So i have been told, Mark .... seems logical to keep the wise choice going so... yeah... bound to be... i think

 

[Kev5]

At least in event of failure it won't interfere with the engine.... phew :thumbsup:

Hi Jo...just so that you know...an interference engine is one where the valves hit the pistons in the event of a timing belt or chain failure. In a non-interference engine the valves do not clobber the pistons so no serious damage is done. This is true with both belt or chain driven engines. The only advantage with a chain is that they tend to last a long time and rarely need changing (unless they become excessively noisy). Belts, of course, need changing at specific intervals and may break if not renewed. Kind regards, BK.

 

[Jot]

reason behind why they do not clobber the pistons being as they are offset
....sorry, did i give the impression of not knowing... am confuddled(which doesn't take much lol)

 

[clix]

I once had a very close call with an 1.6 Orion Ghia Injection back in the early nineties.
Cut out, stranded in the middle of nowhere, tried to start it, over and over with no luck.
Bro arrived with help, definitely cam belt shredded, got me back home, came back the next day with a tow truck and upon investigation, it had missed by millimetres.
Lucky.

 

[Mark]

I once had a very close call with an 1.6 Orion Ghia Injection back in the early nineties.
Cut out, stranded in the middle of nowhere, tried to start it, over and over with no luck.
Bro arrived with help, definitely cam belt shredded, got me back home, came back the next day with a tow truck and upon investigation, it had missed by millimetres.
Lucky.

I had a similar experience with a Mark 3 Escort - just got back home after a fair length trip and the car cut out reversing on to the drive and would not restart

Towed it to the local garage and it transpired the cambelt had snapped but fortunately without any damage to the engine

 

[Kev5]

The early 1980s and 90s ford engines were notorious for snapping cam-belts, petrol and diesel variants.

 

[CaptainHaddock]

Long before my mx5 days, I had a 48000 service on my old Leganza, 2 weeks later, cambelt went taking the engine with it. Needed new internals, head skimming etc, complained to the AA who serviced it and they accepted it should have been changed at the service and covered labour and skimming, I covered parts at cost so was under £250 for the rebuild. Somewhat lucky I feel so was almost happy to contribute. Guess that was an interfering old engine!

 

[Mark]

Captain - you mean you actually owned a Daewoo?!

 

[mx5rod]

Timing chains do not normally need changing unless high mileage or worn I would suspect that a timing chain engine will do damage although if this applies to the cyl head and valves it should be confirmed, the breaking of a timing chain will result in damage to the chain wheels or pulleys the surround ing engine casing and possibly chain guides etc.

So far I have not heard of a mk3 MX5 breaking it's chain but regular oil changes and maintenance will keep it in good order there is usually a hydraulic tensioner which will automatically adjust for wear in the chain and slippers guides so the regular oil changes will keep the oilways clear and keep good flow to the tensioner.

Some cars Nissans, Corsa's fitted with camchains do fail they never snap unless really abused but what happens is the engine management light comes on and reports camshaft signal fault and it turns out to be the stretch on the camchain allowing the camshaft with the sensor on it to move too far from it's position the fix is new chain wheels/gears/guides and tensioner it usually occurs around 60k miles.

I have known timing chains to run to very high mileages in many engines and I would expect Mazda to have a good relaibility record in this area.

 

[mx5rod]

Update : the engines with timing chains are interference engines in the case of a timing chain failure if the chain goes an engine may survive if it stops in the right position but if it s cranked again to start it then damge will most likely happen. if it is towed to start it then it will definitley do damage .