Cambelt snapped

[SuperRedMR2]

Unfortunately friday afternoon the cambelt snapped.

I havent had time to inspect anything but the belt has been shredded.

Hoping there is no other damage

[oukie]

Well the 4age is meant to be valve safe but were you pushing it when the belt let go
Also was the belt old, non Toyota etc.

[FrankBelgium]

Well, I had the same issue last year in April with mine after rebuilding the engine and driving it for 2years (10.000km).
Everything was OEM but I always suspected I over tightened the belt…

It happened while 'cruising' on the highway at 120km/h, I measured the valve clearance and found just 1 exhaust valve slightly out spec so I didn't take the risk to put a new belt and see what happens…
Maybe the fact I had a 20V Blacktop in the garage helped me to even take less risks...
More than 1year later the car is now running the Blacktop with a Megasquirt and I plan to go to the dyno in a few weeks.

So I hope there is not too much damage on the engine and your misfortune also turns out in a positive story!

[Lauren]

To get to a point where the belt snaps it must have been long overdue surely?

It doesn't do any damage, it's a non-interference engine so no worries there.

[SuperRedMR2]

hi lauren,

the belt was brand new and had only covered 1300 mies in 9 months so it wasnt overdue.

[Lauren]

That is very unusual. Was it OEM?

[scomr2]

From memory you've had a head skim and fitted non-stock cams so could well have been some valve / piston contact when the belt snapped.

Extremely unlikely the belt failed this quickly unless there was a fitting error or some kind of mechanical issue in the valve train - needs inspecting carefully to identify the root cause.

You don't seem to have much luck at the moment SuperRed - hope there's not too much damage,

Simon.

[SuperRedMR2]

Thankfully my 206 DMF and clutch were replaced successfully over the weekend at a great expense but at least ive got one car.

Thanks Simon, im hoping its going to be okay.

Im 30 soon and have had 2 mk1s in the last 9 years so maybe time to say goodbye along with my 20s.

[SuperRedMR2]

That is very unusual. Was it OEM?

It was a Gates cambelt so im sure its all my fault for not getting a toyota cambelt.

[scomr2]

Nothing wrong with Gates belts.

[boondougal]

obviously could be the belt but its unlikely.

I agree with the close inspection to find the root cause... i wonder if something else failed first. Bottom pulley rubber or the Tensioner?

Interference or non interference i think you are going to want to try to understand war happened... or it could just happen again.

[SuperRedMR2]

Hi Sam,

I’ve got to remove all of the covers before I can see if there is anything obvious.

The tensioner would be an idea so will be checking that out.

I bought and had an aluminium crank pulley fitted, so I have no harmonic damper, so the bottom rubber isn’t the cause, but that’s not saying the pulley itself isn’t. The alternator belt is still attached so the pulley hasn’t come off.

Like I said above, I won’t know anything until the covers have been removed to root out any obvious cause.

If I have to remove the head, can I use my Metal HG again? I bought it from the USA as I couldn’t find one with the bore I required, so getting another one will take a while.

[scomr2]

TV damper is there to protect the crank not for NVH so makes no sense to remove it.

MLS gaskets are usually single use - is it a cometic one?

Simon.

[SuperRedMR2]

It's a Cometic one.

I do have another idea which could have been the cause, but i'll keep that in the back of my mind until i've gone through the obvious causes first.

[boondougal]

I had a sneaky feeling you had a solid pulley, same here. Hopefully it wasn't that.

Although thinking about it if the dampener is there to protect the crank and ultimately reduce vibration i wonder if a certain resonance would casuse the pulley to throw the belt a bit.

[PW@Woodsport]

A new belt that shreds 1300 miles from fitting quite simply hasn't been fitted correctly.

[SuperRedMR2]

Paul, remember I had low oil pressure - could that have been a factor here?

[PW@Woodsport]

No, the two issues are unrelated to each other mechanically, but both problems do share a common root cause.

[scomr2]

Come on cut him some slack - we've all made mistakes at some point.

[Lauren]

We're just trying to help really. Understanding the problem helps everyone else to avoid it. But I would agree with Paul, something has not been done right.

Belt failure for correct fitment seems extremely unlikely.

Was a new tensioner fitted?