On Jan 28, 1:59*pm, wrote:
On Mon, 28 Jan 2013 02:53:26 -0600, wrote:
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..

That's the Cadillac engine I mentioned in another post.

This whole thing does have me asking how it is that air cooled engines
survive as long as they do? *Particularly the larger ones on garden
tractors, skid steers, etc?

How about aircraft????

Yea, I know they have cooling fins, but hey, people use them all the
time when the outdoor summer temperature is in the 90s, and the air is
still. *Often they are just sitting at idle. *How can they be getting
cooled properly? *Yet they seem to last a long time in most cases. Those
find cant be doing much when there is no air movement, and usually no
fan either....

Are they built from stronger metals than a car engine?

Nope - usually crappy aluminum aloys- Hide quoted text -

- Show quoted text -

It's ok to move your car around without coolant. Not for 5 minutes
though. But you shouldn't need that long. Get everything out of the
way, start the car, move it immediately, shut it off. You'll be fine.