On Sun, 27 Jan 2013 13:50:16 -0500, wrote:

On Sun, 27 Jan 2013 13:45:45 +0000 (UTC), Tegger
wrote:

wrote in news:a949g8p7fatqaffk23cq48p5vnfoqn6q7v@
4ax.com:


2 minutes would likely be safe. 5 would definitely be pushing your
luck.




Even 30-seconds is not safe if there is no coolant in the head. The rad
being missing is NOT the same as simply having low coolant-level in a
complete system.

Combustion temperatures are around 1,500-2,000 degrees F. That heat builds
in seconds if it can't be carried away; without coolant, the surrounding
metal will overheat /very/ quickly, creating the strong probability of the
head warping, which will cause head-gasket failure and poor valve sealing.


Are you a mechanic???
I am. 30 seconds will not hurt ANYTHING. Period. The thermal mass is
highe enough to take a minute of no or light load running without harm
- even on a lightweight aluminum engine. - in most cases significantly
longer.

The Ccadillac Northstar can be driven 50 miles with absolutely no
coolant, without harm - and it is a FRAGILE engine. They do it by
rotating shutdown of cyls and reducing power output.

I would not run a dry engine for 5 minutes - but I have posted a
solution that works very well and is totally safe for a 5 minute run.
- short circuit pipe..


First, I am not a mechanic but I question the 5 minutes. I don't know
the outside temps his engine will be started but my experience shows
my engine reaching operating temps in less than 5 minutes. If this is
correct, then his engine will get pretty hot for a minute or so with
no liquid. As I said I'm no mechanic or mechanical engineer but this
sounds on the verge of dangerous to me. I sure hope he gets
confirmation on what you said, if he thinks you are correct.