Craig, thanks for the photos and update. Irrespective of the money spent, doesn't it'd gladden your heart when you see those refurbished heads ? Looks quite a superb job. It's interesting to see those cracked valves - I had one of those, and do you have any thoughts on why they are cracked ? Overheating, lack of lubrication on account of fuel quality ? Initially, I would discard lean running, because the car had hardly seen any use for some, say, ten years ? I am really surprised with the amount of head deterioration considering the small mileage. What do you think ?
Also, right at the back of the head, is there an oil return hole as on the 6.3s ? I know that there are two return holes in the middle of the heads, but I am not sure about rears. I do know for a fact that 6.3 heads require re-tensioning after about 500 kilometers, and if one fails to do so, the heads will start leaking oil at the back of the heads. I was under the impression , and this is also stated in MB literature, that 6.9 heads, on account of the type of head gasket used, do not require re-tightening. Maybe Helmet may also like to offer his valued opinions ? I have taken note of your thoughts on this matter expressed earlier in the thread.
Last ,but not least, Craig, would you care to put a time factor on this job ? Thirty hours, forty ? Interested in your assessment. Regards. Styria
N.B. $1400.00 for valves - Exhaust only ? $200.00 for guides - Old stock ?