"Full Fan Shroud"
An Article by Larry Paulick
Preface: Larry Paulick explains his new design for a full circumference fan shroud and installation
The Full Fan Shroud
In the rush to get the Tiger out the door, Rootes or Shelby, or who ever, did not provide a full fan shroud for the Tiger.
The results in hot weather, was over heating of the Tiger because the hot air from the radiator, recirculated from the engine side of the radiator, down past the cross member, and back into the front of the radiator. It just introduced the hot air from the radiator back into the radiator.
The efficiency of the fan, and that is Any Fan, is also reduced because the fan was not allowed to pull the air exclusively through the radiator, because of the incomplete shroud. This resulted in a radiator that already had two strikes against it, when it tried to cool the Tiger.
Tiger Tom and Chuck Kings article in the TE/AE Tiger & Alpine Cooling Tales Are All Hot Air http://www.teae.org/tech_tips/hot_air.html is an excellent study of various fans, radiators, electric fans, block offs, etc, to determine what works in the real world with a Tiger at idle an on the road at speed.
If you have not read this article, it is a must to understand the cooling issues of your Tiger.
This dispels a lot of myths, and leads you on the path to a Cool Tiger.
"The Full Monty" or in this case a Full Fan Shroud
Have you ever seen a factory car without a full 360-degree fan shroud? I have not, and the Tiger can benefit from a full shroud as well.
One point in the Cooling Article, was a test, with the same radiator, and fan, but with the stock Tiger shroud compared to a full fan shroud. The results were impressive.
The stock shroud could pull 751 CFM, while the full 360-degree shroud pulled 953 CFM. An impassive 26.7% increase, with the same fan and radiator.
The cooling of any car is dependant on getting fresh air through the radiator, and allowing the fan to draw the air through the radiator efficiently, as with a 360 degree fan shroud.
To fabricate the fan shroud, I took out the original shroud and fan to gain access to the area. I am using the MG Midget R&P, but the process is the same for the Tiger R&P.
I used a piece of aluminum flashing to start the mock up of the lower fan shroud. This alum material is easy to form, cut, and holds it shape during the process. Spend time during this part of the process, as a good form will help in the final product.
After I was happy with the form, I started to make the final shroud using 20 gauge-galvanized steel, to which I transferred the measurements from the alum form. While I cut and welded a section of metal in a portion of the shroud that is bent out too far to hammer form, you can use pop rivets instead of welding to attach this metal.
As with the form, you need to spend time fitting, cutting, bending till you are happy with the way the shroud fits the radiator, clears the fan, and mates to the upper shroud.
Tip You can use a bag of sand, and a soft faced hammer, such as a rubber or rounded plastic hammer, to shape the rounded portion of the shroud. The sand acts as a dolly, and conforms to the shape of the part. This is how the pros do their metal work.
Take little bites of the elephant, or hammer blows, as it is hard to eat the whole elephant at one time.
To attach the lower shroud to the upper shroud, I welded tabs on the bottom shroud, and nuts welded on the backside of the tabs. This way when I screw the upper shroud to the lower shroud taps, I dont have to fool around with the nuts falling and loosing the nuts.
Its bad enough dropping the screws.