Topic

Has anyone experienced a broken inlet camshaft on a non VVC MGF? Camshaft is physically broken adjacent one of the journals, with subsequent damage to valves, pistons and who knows what. The motor had recently had crankshaft oil seal replaced, and has had a new head, timing belt, tensioner, etc fitted in recent months.

I am interested if this is a known issue, a one off, or a workshop error.

Sunlover wrote: wrote:

Has anyone experienced a broken inlet camshaft on a non VVC MGF? Camshaft is physically broken adjacent one of the journals, with subsequent damage to valves, pistons and who knows what. The motor had recently had crankshaft oil seal replaced, and has had a new head, timing belt, tensioner, etc fitted in recent months.

I am interested if this is a known issue, a one off, or a workshop error.

It’s possible the cam sprocket bolts been over torqued when fitted.

The inlet Cam was cracked on my MGTF 115. It looked like the last Garage who did the head couldn’t get the sprocket to fit so forced it on with a windy gun.. then glued the bolt in.. they also fitted cam seals the wrong way round.


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It's certainly not a known issue. This is the first time that I've heard of it.

To add to my comments the Tifs cams had 86k on them and were like new. I would say the damage was done by over torquing the sprocket


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Hi Sunlover, this is bad news.
So, who did the engine rework on this equipment?

Not questioning the comments about the sprocket being over-torqued (I have no experience of this problem) but why would that cause the cam to crack and fail (assuming the fail point was not in the area of the bolt)?

Over tightening the cam rail I could understand, or using the wrong sealent on the cam rail (blocking oil passages), but I just can not picture mode of failure for cam sprocket torque!

It was done by a local (Australia) specialist workshop, who claims experience with these cars. The break is adjacent to one of the middle journals (between cylinders 2 & 3), so I don't imagine it is related to the timing sprockets. I was wondering if it may have been that the timing was incorrectly set?
The car has under 100,000 KM on the clock.

Certainly never heard of this on an MG, but have on a friend's off-road buggy. That turned out to be due to an over torque error when converting foot pounds to NM.

Im not sure about how consumer rights work in Australia, but here in the UK you would have a simple warranty claim against whoever fitted it. It is not something that should happen in normal use, and either parts fitted were of poor quality or were fitted incorrectly. Garage should be buying and fitting a new engine at their expense. You might also have grounds to claim for a hire car while it is off the road too.

It almost certainly will need to be a new engine from what you described sadly.

G0RSQ wrote: wrote:

Not questioning the comments about the sprocket being over-torqued (I have no experience of this problem) but why would that cause the cam to crack and fail (assuming the fail point was not in the area of the bolt)?

Over tightening the cam rail I could understand, or using the wrong sealent on the cam rail (blocking oil passages), but I just can not picture mode of failure for cam sprocket torque!

Totally agree but it rears it’s head on the 75 OC every now and again. More KV6 then K-Series mind, but my wallet is still smarting from what should have been a simple belt change. Wish I had photographed the damaged cam and sprocket. They were a real mess.


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I've just been chatting with Russell Walsh of MGRoversolutions and he's never come across this type of failure. And He must have had thousands of these engines apart!

Possible manufacturing fault or cam has been damaged/ dropped prior to fitting.

He says that even a worst case engine blow up leaves the cams intact.

If you post pictures onto the forum of the cam. Damage, Russell will have a look at them.

That's a real shocker . Are you going to find another 'specialist ' to sort it ? Where do you plan on getting the parts from?

John .

David Aiketgate wrote: wrote:

I've just been chatting with Russell Walsh of MGRoversolutions and he's never come across this type of failure. And He must have had thousands of these engines apart!

Possible manufacturing fault or cam has been damaged/ dropped prior to fitting.
He says that even a worst case engine blow up leaves the cams intact.

If you post pictures onto the forum of the cam. Damage, Russell will have a look at them.

Working on the Ford Duratorque engine for London Taxis, the cam carrier would have the bolts forced out of the casting when the pistons said hello to the valves but I never saw a cam shaft break . It's probably been dropped .
John