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Would you, and if so, for how long?

I may want to test the new clutch release bearing I'm fitting to try and solve the idle speed dropping when I press the clutch (another topic) but I already drained the coolant to resolve the coolant leaking from the 11th stud problem (also another topic). I don't want to refill the coolant and find that the release bearing doesn't solve the problem and then the engine has to come out.

I shouldn't need to run it for very long to determine if the idle speed is still dropping.

Just fill it with plain water, I do that with fresh engines, because, you just never know (and you also need to do it to let the gasktes seal properly).

But, coming back to your question, about 5 minutes should be OK, however the water pump seal won't like it too much, so let the fan belt off first.

I never run a engine without coolant. It was explained to me by a race engine builder that the hottest part of the engine is the head around the combustion chamber and it doesn't take but a few seconds to get too hot without coolant around it. Second was the water pump seals do not like to run dry for any length of time and will self destruct.
It makes sense to me so I have never run an engine "Dry" It may well be a lot of bo**ocks but I'm happy to just fill 'er up with plain water....................

In contrast to Minimans information, I do remember advice from several builders using the Payen BK450 gaskets that said specifically to run the engine without coolant. Their advice was to start the engine, run it long enough that you could feel the cylinder head starting to get warm. Then switch off and re-torque the cylinder head. The reason they gave was that the heat allowed the coating on the gasket to better bond with the head and block.

Personally... I never had the guts to take their advice. I do like Spider and make the initial start with water and after a few heat cycles drain the water and replace it with antifreeze.

minimans wrote: It was explained to me by a race engine builder that the hottest part of the engine is the head around the combustion chamber and it doesn't take but a few seconds to get too hot without coolant around it.

Respectfully, I gotta say, that's not at all right. The time it takes for heat transfer through the Cast Iron from the combustion Chamber to the Cooling Jacket is in the order of several minutes. So, maybe a few mintes, but certainly not seconds. Further, keep in mind, in this case, that the OP isn't driving his mini, so there won't be any load (no load means next to no heat), nor would I think he'd being going anywhere near WOT.

I second that opinion. A few minutes is completely fine.

Hi there - if its of any use - I did this by accident Probably ran for a couple of minutes. Really scary at the time - but a hillclimb and sprint session later and no problems have emerged. Lucky I guess

You can, but you shouldn't.

Rather like using a chisel as a screwdriver.