<VV> A question about engine noises...

[Tony Underwood]

At 05:33 hours 06/15/2005, bjornyesterday wrote:
>List Members,
>
>Is it possible to take the fan belt off and start a Corvair engine?


Sure.


>Strange engine noises could be detected without the noise of the fan,
>idler pulley, and generator/alternator.


This is pretty much policy for troubleshooting strange noises.


>How long could one run an
>engine without the belt before doing damage?


It takes a couple of minutes of idle for a Vair engine, even without the 
belt, to reach normal operating temps...  cylinder heads and cylinders, NOT 
oil temps, which will still at this point be relatively low.    About 
another minute or two past that (still idling) and it will begin to 
overheat the heads and oil temps will start to rise.   Another minute or 
two past that, if idling, and it will usually  "protect itself" and shut 
off because of fuel metering problems, usually over-rich, caused by fuel 
boiling over in the carbs caused by the overheated heads, flooding the 
engine.   Even at this point it's not likely that any real damage to the 
engine has resulted, but I'd not wanna press my luck.    Overheating 
cylinder heads is what helps loosen seats.


I would NOT depend on this little self-preservation response from the 
engine to keep you from cooking something.    A couple of minutes with the 
fan belt off is plenty of running time to troubleshoot odd noises.   And of 
course if that little red TEMP lite on the dash cluster should  pop on, 
shut it off NOW.   (don't confuse the ALT or GEN light with the TEMP light)

I've seen people who dragraced Corvairs simply remove the fan belt before 
the "money run" so as to reclaim the ~15 HP it takes to spin the fan at 
5500 rpm or thereabouts, and that's flat out down a dragstrip and the quick 
trip back to the pits, no fan belt.

There are other dragrace engines (water pumpers) which use no cooling at 
all, block cooling passages filled with concrete to help stiffen the 
crankcase.   Ten seconds of wide open throttle isn't long enough to 
overheat anything, and half the time these engines aren't fully up to temp 
when the car is staged at the lights anyway.

Don't be afraid of damaging anything by idling the engine with no fan belt 
as long as you don't leave it running that way and go have lunch.



tony..