Dear Grandpa Nick:
We’ve heard a lot about aluminum heads lately. but I’m wondering if it’s not mostly propaganda just to stir up interest in someone’s product. Seems to me the aluminum head would be less efficient and actually more expensive to manufacture.
Donald Barton, Dallas Texas
Answer
It’s certainly true that heat is power and because of its great transfer characteristics, aluminum definitely does reject more heat (power) to the cooling system resulting in somewhat lowered efficiency. However, the combustion chamber temperature is considerably lower titan in a comparable iron head, permitting the use of a higher compression ratio. Fortunately, the higher allowable compression ratio more than compensates for the greater heat loss.
While it’s true that aluminum castings are more expensive than cast iron aluminum castings can be made to closer dimensional tolerances – often completely eliminating many machining operations. Aluminum is far easier to machine (larger cuts, faster manufacturing speeds, etc. ) , and all considered, the aluminum product cost now approaches that of cast iron-and it’s a heck of a lot lighter!
Note: Also remember that different heads take different stud kits, plugs and even at times different Thermostats. Not all of them match the stock equipment. So it’s best to make sure and check with the manufacturer when you order as to what parts you will need.
New Series: This question was asked in the summer of 1960 to Grandpa Nick. But if you would like to ask a question, we would love to continue where Nick left off. Please head over to our contacts page: HERE and shoot us a Flathead question. Your question might just help others who are wondering the same exact thing. We would like to make this a weekly Series.
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