Ignition off

[batwick]

Has anybody experimented with rewiring tweaks in order to make the following work with the ignition OFF: 1) Boot release 2) Engine cooling fans (1996 Griff 500) Patrick Buckland

[macca]

I wouldn't rewire the boot release unless you want to risk somebody helping themselves to your golf clubs (or whatever). There's no point have the fans going when the engine is off - the pump isn't running so you're only cooling the water in the radiator.

[batwick]

I was thinking of mounting a hidden, unswitched auxilliary button to release the boot. Keeping the radiator fans going after the engine stops is pretty important, as it causes a heat differential between the water in the rad and the water in the engine, which in turn causes circulation of heat (not necessarily water) by convention currents. This prevents heat soak, which can fry an engine that has been thrashed and is then suddenly stopped, full of boiling hot oil and water and with no air-flow going past it! Your engine temperature can actually RISE after its turned off because of this. Patrick Buckland

[macca]

quote: Keeping the radiator fans going after the engine stops is pretty important, as it causes a heat differential between the water in the rad and the water in the engine, which in turn causes circulation of heat (not necessarily water) by convention currents. Patrick Buckland

Nice answer, not to be too picky but it's convection rather than convention . I reckon the heat would not have time to dissipate before it boiled after a good thrashing, so have to disagree with you - It would stand more chance of cooling by convection if the radiator was much higher than the cylinders since cold water will naturally fall rather than rise - I may be wrong and am willing to stand corrected. Edited by macca on Monday 24th September 23:30

[WalterU]

after you've thrashed the engine, you should let it run in idle for 2-3 mins. to cool off. Particularly important with turbos ... Rgds, WalterU