Hi Nathan,

I'd say that extended running above 450 is to be avoided. Get off the
gas ASAP and it'll drop back to 450 or less and you'll be OK.

Running past 550 is going to reduce the life of the engine.

The valve seats often don't drop at high temp... they drop when the
engine cools down and the seats shrink. When my bus dropped the valve
on the way to JBB it ran fine all the way from Scarborough to Fort
Erie, but when I restarted it after our breakfast stop at the Duty
Free I knew immediately that the seat was FUBAR. I had not passed 425
at any time that day.

There are lots of variations on this theme. As they say: Your Milage
May Vary.

Happy Trails,

Greg Potts
1973/74/77/79 Westfakia "Bob The Tomato
www.pottsfamily.ca

On 24-Jan-07, at 2:07 PM, Nathaniel Poole wrote:

> With all the issues of popping valve seats on the AC engines, does
> anyone
> have an idea what is the redline temperature when this is likely to
> occur?
>
> Nathaniel