Fg Droped A Valve

[ratter]

not here to argue at all, just posting actual events that have occurred that we have seen, not hearsay

[arronm]

Me neither just comments on my observations. Engine failures can be difficult at times. But in the end its always about who is going to pay.

[blueprintbullet]

Thanks guys I do appreciate your opinions even if our views differ slightly

[discostig]

Wow I only just read this thread, terrible luck blueprintbullet. What I'm taking away from this is I need to change my driving style immediately. I had the timing chain on my BFII jump a tooth but this was only picked up during a valve spring install at XFT. The car had done just shy of 200,000km and who knows how long it was like that as the car drove fine!

I have a habit of jumping off the throttle rapidly to produce maximum flutter. Not any more! It also sends huge driveline backlash through the car sometimes. A good reminder to drive with "mechanical sympathy".

Wish you the best luck dude. I'd be pretty devastated if mine got lunched.

Edited 18/08/13 12:27 AM by -SteveR-

[blueprintbullet]

Hi All

Having had the Engine Exchange complete the report on the engine I can now confirm that even with the valves being bent they did a vac test on the cylinders and showed that they were still sealing within 80% of perfect which according to them is more than acceptable to have the vehicle run properly.. I also have spoken with another dealership who have confirmed that if the cams were out by two teeth in advance then there is no doubt that the pistons will have kissed the valves. It has also been suggested that I bolt the head back on and advance the cams by two teeth to see if there is any contact which I will do. That said Nuford have still got there heads in the sand just hoping I will go away but that's not likely to happen. For those who have suggested it would be easier to put my hand in my pocket and just fix it well you are right but that said Im not going to back down now its just not right.

[ratter]

well I guess not all motors are the same then or my customers have been extremely lucky

[blueprintbullet]

Well here are the facts

The motor has only ever been opened Twice firstly by Nuford two years when the car had a cam timing issue and now.

When the motor was opened this time the timing was correct.

There are identical dents in all of my pistons which are carboned over suggesting it has run with these dents.

According to the report when Nuford repaired the timing issue it was two teeth to far advanced.

The cam phasers will always start at 10 degrees camshaft advance ( that's 20 degrees crankshaft retard).

Two teeth means that the cams are a further 17.14 degrees further advanced or 34.28 crankshaft degrees retard.

This motor at startup would have had the valves opening 54.28 crankshaft degrees too early.

Due to the fact that the camshaft phasers allow upto 50 degrees camshaft retard, or 100 degrees crankshaft advance, these motors have large recesses in the pistons to clear the exhaust valves as the exhaust valves can be nearly completely open at full camshaft retard when the piston reaches TDC.

The intake valves are larger than the exhaust valves and as such need more clearance so they dont hit pistons but there is no recess for the intake valves in the pistons as under normal operating conditions they shouldnt be anywhere near each other.

This image isnt for a barra but is good for a referance.

To advance the camshaft timing move TDC to the right and you will see that at 54 degrees the intake valves are about 3/4 open

To see the motor in full camshaft retard move TDC 100 degrees to the left

[jas98]

are you sure it was 2 teeth out not 5? lol. I have herd of countless numbers of cars haveing 2 teeth out and after correcting has been fine for years to come.

[ratter]

correct which is what I have seen, I have seen 3 teeth out and no issues except for the warning light

[blueprintbullet]

It all depends on if it was advanced or retarded! mine still lasted 2 years without failing.