Board index Flathead Power-Technical Questions, Answers, and Suggestions Knuckles Replacing valve seats

Replacing valve seats

Moderators: Curt!, Pa

Post Sun May 11, 2014 8:31 am

Posts: 299
Location: Cranbrook B.C. Canada
I did a search and can`t find any info. on replacing valve seats? I`m wondering how much interference fit when installing new seats in these old cast iron heads??
Thanks in advance.

Post Tue May 13, 2014 11:56 am

Posts: 150
Location: Carver, MN

Way back in the dark ages, the factory service schools gave a figure of .004" to .006" press fit for cast iron heads. I have never felt comfortable with less than .005" and generally aim for .0055" to .006 on Knucks. I also heat the head in an oven and freeze the seats for installation which will make them go in easier.

Post Tue May 13, 2014 5:12 pm

Posts: 299
Location: Cranbrook B.C. Canada
Thank you Lee, I have replaced lots of seats in shovelheads ,but this is my first time replacing Knuck seats .
I`ll be sure to take pics. along the way.

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