6 Blade cooling fan for 64 BJ8, advice?

[John Turney]

I've been asked for photos. Because the car is together, you don't get much of a view.

 

[RAC68]

Hi All,

Keep in mind that the sleeve thermostat closes off the bypass when fully open and the bypass, if left opened, would divert as much as 25% of the coolant from passing through the radiator. This loss of radiator-cooled fluid would increase the operating temperature of the engine and create the potential for overheating.

Now consider a thermostat starts to open at its rated temperature and is fully opened at approximately 15-20 deg. F or so above its rating. Assuming the same holds true for falling temperatures, the thermostat would begin to close when the coolant temperature fell to its rated temperature and begin to open the bypass. At about 15 deg. F below the rated temperature, the thermostat will be fully closed and bypass fully opened.

Now, based upon these understandings, choosing a 160 F sleeved thermostat, over a 180 deg. F thermostat, the engine should warm to 160 F when the thermostat begins to open and is fully open at around 175-180 deg. F. As engine operating temperature increases in traffic on a hot day, starting at a lower full coolant flow temperature should provide greater time and resistance against overheating. Additionally, should modifications to the cooling system prove successful enough to cause coolant temperatures to fall below the rating of the thermostat, a minimum operating temperature would of 160 deg. F would be aggressively maintained by the closing of the thermostat and opening of the bypass.

Since an optimal operating temperature of a Healey engine should be at around 195 deg. F or so, the choice of a 180 F thermostat should be just fine for summer driving. However, our cooling systems suffer from period engineering issues and would require major engine compartment redesign to overcome. Yes, a number of smaller modifications can achieve some cooling benefits, however, we are still trying to overcome original design issues caused by misdirected, uncontrolled cooling air input and escape flows. along with the often forgotten engine coolant bypass.

So, is Tahoe Healey's unmodified cooling system experience unique. I would say if not unique, uncommon, as I haven't had a similar experience even when my Healey was brand new.

Just my thoughts,
Ray(64BJ8P1)

 

[RAC68]

Hi All,

Yes, it is difficult to take pictures of the installed shroud. My attempts were even more difficult as I had painted the panels flat black purposely fade into the background. Keep in mind that I have also added forward panels, extended from the shroud, to enclose the path between the radiator's core and Healey grill.

Hope this helps,
Ray(64BJ8P1)

 

[tahoe healey]

Ray, are you saying that later opening of the thermostat due to a higher rated (190 degrees verses 160 degree)allows more cooling? If your Healey runs at 185 normally, the 190 thermostat would not allow coolant to enter the radiator whereas a 160 would be open and the fluid would be cooled. I am confused. This is not what I was taught almost 60 years ago. I still have my text book somewhere. I'm probably wrong due to my age.

 

[RAC68]

Hi Tahoe,

NO. If that is what you got from my statements then I am a bad communicator.

My point was that by having a 160 sleeve thermostat, it will open and cut off the bypass earlier and allow full flow of engine coolant through the radiator. The 160 will also close later (at a lower temperature) then the 180. As a result, on a hot day or in traffic, the earlier open will provide all engine coolant flow through the radiator at a lower temperature and start to attach rising temperature sooner.

I am confused by your interpretation of my entry and have reviewed it to see how I miscommunicated. However, I still have no clue how you could have interpreted my statement in the way you did.

Ray(64BJ8P1)

 

[tahoe healey]

We'll blame it on old age and solitary confinement.