As some may know, my Coupe threw its aux belt into the cambelt at Curborough a couple of weeks ago - Paul has now found the time to get the cylinder head off - it's now clear that the belts went as the throttle was lifted at very high rpm, as the damage is considerable - here's a few pics...

Remember - all of this damage was caused by a cheap-to-replace aux belt - here's what's left of it

The cambelt didn't fare any better - note the small piece of alloy casting...

...which was a piece of the oil pump housing

The good news - six of the valves aren't bent....

All of the inlet valves showing contact marks

However, the pistons are thankfully OK

Close-up - I'm very pleased with the condition - shows the fuelling is good

Slight marking discovered at the top of the bores on a couple of cylinders

Another indication of good fuelling - this manifold is off to Barbz for matching to a new head

So - it looks like a rebuild is going ahead. Paul is going to pull the pistons out anyway, just to make sure that the rings are free in the grooves (the shock can sometimes trap them). Also, on Barbz's advice, we're going to replace the big end shells, even though they were only done 100,000 miles ago when the Accralite pistons were fitted.

This cylinder head was one of Barbz's early ones - in the seven years or so since I had it fitted, I reckon it has paid for itself several times over, in the form of improved fuel consumption - my MPG jumped by around 5mpg after it was fitted, and with my mileage at 30,000 a year, I soon got my money back and started making a profit.

Barbz will be building a new head for me, using all of the knowledge he's built up about Coupe heads in the last seven years. However, because there is no damage to my current head, I will be having new valve guides and replacement valves fitted and I will be selling the head, in order to recoup some of the costs. So - if anyone is in the market for a genuine, proven Barbz head at a discount price, let me know (or you can buy as-is and fit your own valves and guides.

The moral of this story is that aux belts are very cheap to replace - cylinder heads are not - my car is probably one of the best-maintained on the forum (aux belts were done a couple of years ago), but this still happened - I will be changing my aux belts annually from now on.

What nightmares are made of!

Carnage,

Most failures cause the crank pulley to eat the oil pump.
Nice to see Paul doesn't reuse the crank pulleys after failure.

The one I featured on my website put so much force on a new cambelt that it sheared the exhaust pulley off the camshaft.

A reminder that these aux belts should be replaced yearly minimum on high powered cars.

Anyway never a better time to get Barbz to build you a 2.5 then I can have some competition at curborough next time
And a belt guard if your going to maximise the use of the aux belts.

Some of those pics are quite shocking! For how much it costs I think I'll change the aux belt every year from now on.

No competition - I'll beat your time with a measly 400-ish bhp and 2 litres....

I can't afford to get Barbz to build a 2.4 / 2.5 and in any case, mine is fast enough - going to concentrate on handling now

While the car is at Paul's, waiting for the new Barbz head, the rear subframe is coming off and having polyurethane bushes fitted, and a new 24mm Whiteline rear ARB. New front discs and Carbotech pads will also go on, plus a pair of new wishbones (bottom ball joint has play at both sides)

With the Quaife, it was already handling very neatly, but these changes should help it along quite nicely....

2.5 is extremely economical.

What bushes do you use for the subframe as mine have been shot for years?

Poor old long suffering Wifey I think some flowers are in order...!

This cylinder head was one of Barbz's early ones - in the seven years or so since I had it fitted, I reckon it has paid for itself several times over, in the form of improved fuel consumption - my MPG jumped by around 5mpg after it was fitted, and with my mileage at 30,000 a year, I soon got my money back and started making a profit.

Barbz will be building a new head for me, using all of the knowledge he's built up about Coupe heads in the last seven years. However, because there is no damage to my current head, I will be having new valve guides and replacement valves fitted and I will be selling the head, in order to recoup some of the costs. So - if anyone is in the market for a genuine, proven Barbz head at a discount price, let me know (or you can buy as-is and fit your own valves and guides.





You are joking surely Nigel. I would not touch that head if you paid me !!

Why? - it has bent valves, nothing more.

Painful viewing those pics

Nigel - you must get Paul to fabricate an aux belt guard for you, would have saved all of this.

Mine has saved me from 2 aux belt failures, once on a dyno and once whilst driving locally around Bristol. One time the aux belt was less than a year old.

These are surely THE best preventative mod for our cars, for the minimal outlay saved a lot of £ for certain

Because in my opinion if someone is going to have a torqueitalia stage head, then i cant possibly see that buying a head that has had a severe jolt etc would be a sound investment.
We / you know how expensive tuning a coupe to reliable high horse power is.

So why on earth would taking such a risk with that head be a sound tuning investment.

I realise that many may not agree,but its my opinion.

Nigel, bad times. Mine went at low throttle and caused similar damage, so I think you've been Lucky. How you haven't thrown the towel in yet. I would have.

With regards to the aux belt I'm almost certain now that it isn't just an age related problem. With the way they all peel to give a whip on the inner edge it has to be a runnout problem or pulley alignment.

It got me thinking. Mine was a goosed power steering support bearing causing runnout issues. I believe proccy's was found to be an alignment issue of the alloy ancillary mount. I wonder if you have an underlying problem, crank end-float for example?

I also agree with this.

Like Nigel said, only the valves got bent. With new valve guides and valves, as long as they are seating properly, there would be nothing wrong with it.

Post 80's engine development took into consideration that most engines would have to be an interference fit to optimise valve lift.
This meant that future engine development would utilise various valve guide systems.
The valves are extremely strong and would take the weight of the car on its strongest point.
However just like a formula 1 car's wishbones strength these valves were designed to bend given abnormal forces from a certain angle.
The side effects are damage to the guides only.
A very easily replaced component:

It's no different having a faulty track rod end.you only need to replace the joint not the rack.

The main concern in such a failure would be the potential damage to the pistons or the big end bearings.
This is currently being addressed on the rebuild .

The valves are extremely strong and would take the weight of the car on its strongest point.
However just like a formula 1 car's wishbones strength these valves were designed to bend given abnormal forces from a certain angle.
The side effects are damage to the guides only.
A very easily replaced component - JBT -

Sounds spot on to me. The forces seen on the head were those sufficient to bend the valves. If they weren't the pistons would have see more force and so more damage.

Good luck with the rebuild Nigel

Nigel why are you having another head done rather than use this one?
Is it a stage 1 effectivly and you now going for stage 2 and more power as if not whats the point in having another if your only having the same?

Hi Dave

I wondered that as well, but Barbz said he would prefer to work from a 'virgin' head, rather than re-work mine.

This suits me fine, as I'll be able to recover some of the cost by selling the original head once its had new valves and guides fitted

I'm doing something a bit more enhanced for his current setup.

Well thats ok then but as nigel said himself there is no need for another head just that you are doing somthing diffrent for him. by the looks of his comment above it looks like he is having the same tho not somthing diffrent and also looks like he was/is unaware of this?

Then, i'm sure he will be pleasantly suprised.

Dave your right.
It makes more sense for Barbz to wait a few weeks for Nigel to Remove the head and send it down to him than it does to rework one he knows is good and in his workshop.

John no need for the sarcasm I was only wondering why Nigel would get another head done when it would be cheaper to have the existing one sorted if he is only having the same spec so thanks for your comment

Always need for sarcasm with you David.
Your a funny guy after all.

Such a simple question inspired the response.

Guys - I spoke at length with Barbz at the AGM a couple of weeks ago. I also assumed that he would re-work my head, rather than start with a stock head.

However, he said that he would prefer to work with an untouched head, as he would be able to apply everything he's learned since he did mine all those years ago.

Also, Barbz will be doing something with my manifold, I believe around the collector area.

Finally, he'll be specifying some custom cam settings for my C&B cams

I'm not after big power gains, although if I get some more, I won't be complaining. My main aim is to increase the low and mid-range and to improve spoolup. My turbo is capable of rather more than it gave last time Leighton mapped the car (mostly down to the injectors being maxxed out), so I'm hoping that a new head, some new injectors and a remap will realise the true potential of the billet compressor wheel on the GT3071.

Along with the handling tweaks that will be fitted while its waiting, the car should come back feeling pretty good.

Sorry again Nigel
So it looks like it let go at high revs when I lifted off to brake at the end of the straight? Strange I didn't notice any lights or lack of engine note until I had turned in to the corner. Maybe you would have noticed it immediately knowing your car more intimately.
I look forward to seeing it running again mate.

I didn't even mention getting the head reworked as it would not need to be reworked and as my question was to Nigel not to you so there was no need for your response thanks again.

Nigel sorry for taking it OT but I'm glad your getting it all done and I'm sure you can get a few more horses from it now as had been said Barbz knows a fair bit more about it now than what he did 7 years ago so best of luck

Senny Dave - I would have been happy with new valves and guides, but Barbz made me an offer I couldn't refuse, which included some new work that couldn't easily be carried out on my existing head. Don't ask me what it is - it's well beyond my understanding, but if Barbz says it'll be better than what I've been running so far, I believe him

Fishy Dave - yes, it looks like the aux belt started to come off at high revs, probably as the throttle was lifted - however, it could have been a couple of seconds before the shredded belt found its way into the cambelt. Again - don't be sorry - there was nothing you could have done to my car that I wouldn't have been doing to it when I next drove it - in fact I would probably have been driving it harder than you would ever have done - just one of those things.

Thats fine as do I, I just wondered why you were going with a new head as it seemed you were only after the same power and as we know the rebuild isn't cheap without the cost of another head, But I'm sure the extra power will also be good and liked