RE: Re: oil cooler/oil heat exchanger combo?

[Jonas Karlsson <jkarlsso@metabolex.com>]

Scott F. Williams wrote:

> I think that the key here is being able
>to control the heat exchanger with either a manual switch or a 
>thermostat of it's own. After it warms up sufficiently, it should stop 
>circulating engine coolant through itself.

neat idea, but you still have the problem of the heat exchanger 
unnecessarily and detrimentally cooling the oil before everything gets 
hot. of course with a manual switch, this too can be controlled. 

But the question arises; If you are going to shut it off whenever the car 
gets hot, how is it helping you cool the oil during hard driving? It 
seems with this setup, you are improving  cooling ability at medium 
operating temps, and I havn't had any problems with overheating at mild 
temperatures, have you? :-)

going with tradition of contradicting myself, however, here's the 
flipside. The exchanger works to cool the oil whenever the water temp is 
lower than the oil  temperarure. So with a manual switch, accurate oil 
and water temp gauges, and a big efficient radiator, one could use the 
exchanger to control oil temps. You'd just have to keep an eye on the 
temps and if the water temp was ever higher than the oil temp, then shut 
off flow. You might be able to rig this electronically if you used 
identical temp sensors, and a solenoid for the manual control (see 
below). just a thought.  


> Hmm... How could I rig this?... Somehow, use a regular thermostat but 
in >reverse position? -but mounted in what? 

well, most thermostats that I've seen are the kind that open when hot, 
I'm sure there are ones that close when hot, but they are probably 
pretty uncommon. Anyway, to use a open-when-hot thermostat, you would  
need to set up a bypass hose for the heat exchanger. That way, when hot, 
the thermostat would open and coolant would mostly flow through the 
bypass. Difficult, and a PITA if you ask me. :-)

>Or if I did  a manual switch, what kind of valve would do it?
>

you could use the same kind of valve that controls flow to the heater 
core. connected inline with one of the hoses for the heat exchanger. Is 
this for a rally/race car? If so, then you probably don't need the 
heater controls and you could use the stock location for your "manually 
controlled/variable flow oil cooler system." Or you could control the 
valve with a solenoid mechanism and electronic signals from the water 
and oil temp senders. 

whew,  HTH

Jonas
85 Scirocco 



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