BX Turbo Diesel Cylinder Head

G4EIY · Unread post by **G4EIY** » 28 Aug 2004, 01:34

Hi,
I have been donated and engine, but of unknown quality.
There are cracks between the inlet and exhaust valves on two cylinders, but the cracks do not continue below the valve seat inserts in either of the ports.
Is the head for the scrap bin, or is there a chance it would be usable ?.
Cheers

AndersDK · Unread post by **AndersDK** » 28 Aug 2004, 02:48

This kind of cracking is very common around the swirl chamber outlet, have not seen it as shown in the picture.
If the cracking has no immediate influence on compression, I would simply consider it normal wear signs on a standard diesel, and then re-use the head.
Note that the worst killer to the PSA diesels are restricted flow in the cooling systems. Should <font color="red"><i>always</i></font id="red"> be considered the main cause of a HG failure [B)]

G4EIY · Unread post by **G4EIY** » 28 Aug 2004, 03:39

Thanks Anders,
Likewise, I have not seen this cracking before on BX heads.
I have now removed all the valves, but somthing else was strange, note the burn marks on the bottom edge of the exhaust valve, there is no valve seat contact at this point, indicating a distorted valve seat.
This also shows up on the other cylinder where similar cracks are evident, but on the inlet valve seat.

AndersDK · Unread post by **AndersDK** » 28 Aug 2004, 04:10

Your latest findings seems to be the result of the usual tinkering with the turbo diesel :
Restricting the waste gate (increasing boost) or simply increasing fuel, even both [:(]
Cant see other causes as it must be caused by overloading (overheating).
As long as it goes - it's really fun - but usually it does not goes for long [;)]

G4EIY · Unread post by **G4EIY** » 28 Aug 2004, 13:30

Other interesting observations:
1. There was a large build up of carbon on the inlet valves, although quite soft, virtually none on the exhaust.
2. The head has been skimmed without removing the swirl pots, I always thought it good practice to remove the pots, skim, then measure the depth of the pot and remove any metal required to achieve the correct projection above the head face.

tomsheppard · Unread post by **tomsheppard** » 29 Aug 2004, 13:14

Distorted valve seat? Bent valve more likely!