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 Posted by: Aaron ® 04/19/2005, 16:30:42 Author Profile Mail author Edit I need help in this area since to be honest, I have no clue. With the spark plug diameter of 1/2" and being steel, screwed into an aluminum head that has 5/16" width of threads.(about 3.25 turns till tight) Is this enough threads to hold the spark plug in place, or to not loosen? Any specifications, standards or any other help is appreciated. Thanks, Aaron

 Replies to this message

 Re: Spark plug in an Aluminum Head Questions?? Re: Spark plug in an Aluminum Head Questions?? -- Aaron Post Reply Top of thread Forum
 Posted by: dvbswamy ® 05/15/2005, 11:54:27 Author Profile Mail author Edit dear aaron, in any machine design, the minimum depth to which any threaded part is to go is equal to its diameter. that is D=L. more or less sqaure. that is enough to hold in any ENGG material, including aluminium. the Al used in normal engg. practice is Al alloy and has better strength than pure Al. i am not sure if answered your doubt. let me know if i did not. al the best. Prof. Swamy.

 Re: Spark plug in an Aluminum Head Questions?? Re: Re: Spark plug in an Aluminum Head Questions?? -- dvbswamy Post Reply Top of thread Forum

 Re: Spark plug in an Aluminum Head Questions?? Re: Re: Spark plug in an Aluminum Head Questions?? -- randykimball Post Reply Top of thread Forum
 Posted by: Daver ® 07/27/2005, 00:38:11 Author Profile Mail author Edit Can someone define the minimum thread engagement for a Spark Plug in an Aluminum head without doing a detailed stress analysis? I realize that a best practice might be l/d=1. What I would like to determine is the minimum number of threads based on strength of Aluminum, normal combustion loads and number of cycles. If there is an engineers handbook that takes these type of factors into account it would be a big help.