5 GT Turbo Cylinder Head cracked between Valve Seats

[Woznaldo]

Evening All,

I pulled my Head apart yesterday to prepare it for the new Cat Cams Valve Springs and Retainers and all is well apart from there's a crack between the Valve Seats of the No.1 Cylinder. Here's a pic:



Does this mean my Head is FUBAR? I never had any issues with the car running before hand?

 

[DaveL485]

It can be repaired by a specialist, but another head might be more economical. I would only repair that if the head was very hard to get/expensive, or if it was heavily modded and would cost more to repeat the work to a new head, than to fix it.

 

[Andyquadra]

it'll need the seats grinding out, grind the out the crank and tig weld it up and then refit new valve seats. I'd guess a good couple of hundred to do it

 

[Woznaldo]

Thanks for the replies gents. I do have another Head, but as Dave has eluded to, this one has had work done to it.

I'll strip the other head down and see what condition it's in and go from there. I can also compare the work done to the cracked Head.

 

[DaveL485]

Thanks for the replies gents. I do have another Head, but as Dave has eluded to, this one has had work done to it.

I'll strip the other head down and see what condition it's in and go from there. I can also compare the work done to the cracked Head.

Saying that though I have no idea of engineering costs where you live bud, it may cost you a quarter (or double) what I would expect to pay. As Andy said though thats a grind out, weld, machine and refit valve seats so not a quick fix with a welder.

 

[Woznaldo]

I guess the other question is, what will possibly happen if I do nothing?

 

[Andyquadra]

I guess the other question is, what will possibly happen if I do nothing?

the crack will probably keep opening and find a water way

 

[DaveL485]

Or a bit of head material might fall into the cylinder? Valve guides will disrupt and not seal properly, cooling system pressurisation... leaving it wouldnt be an option for me.

 

[Woznaldo]

Yeah, I'm thinking it can go one of two ways. One, as you say, the crack could continue to grow. Two, now that it has cracked, the stress has been removed and it won't get any worse. Unfortunately I don't think I'll be able to foot the bill for a repair in Australia and might just have to 'suck it and see'.

 

[DaveL485]

Two, now that it has cracked, the stress has been removed and it won't get any worse.

Sadly it doesn't work that way buddy. The critical flaw in the metal will continue to grow with the constant heat cycling, stresses of a running engine and so on.
Thats not just a home garage monkey talking either (for a change), I studied materials science many moons ago and learned a few useful nuggets about the way metal 'works'. Although what you can see suggests the crack has terminated at both ends I feel it will probably go upwards in the third plane as well, and continue to do so until its all the way through. Might take a while (might not) but you should at least get a quote for the work to see if it's do-able. I'd not pay more than £150, maybe £200 all in.

 

[Brigsy]

Nothing to worry about at all this is standard crack on a used gtt head. The van has been like this for years and still pulls 230+hp every time on the rollers. If it ain't broke....mine has been the same for at least ten thousand miles.

 

[Tony Smith]

Sadly it doesn't work that way buddy. The critical flaw in the metal will continue to grow with the constant heat cycling, stresses of a running engine and so on.
Thats not just a home garage monkey talking either (for a change), I studied materials science many moons ago and learned a few useful nuggets about the way metal 'works'. Although what you can see suggests the crack has terminated at both ends I feel it will probably go upwards in the third plane as well, and continue to do so until its all the way through. Might take a while (might not) but you should at least get a quote for the work to see if it's do-able. I'd not pay more than £150, maybe £200 all in.

You leave us home garage monkeys out of this! :0)

 

[Brigsy]

You can refit this and not worry about it to be honest. I bet 80% of the gtt's out there have the same issue.