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Odd question

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jcatnite

jcatnite

Jedi Knight
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My workshop manual lists the bore size for the 1500 pistons as 2.8995 - 2.900 for Grade F and 2.9001 - 2.9006 for Grade G. I'm wondering what determines which grade a piston is? Perhaps I've spent too much time looking in the book and should go clean some more parts.
JC
 
My guess is the machining varied enough that Leyland had to use different sized piston based on how much slop occured during machining of the block. I have seen this on some older engines(51 Dodge) in the past.
Also the same can be said about the pistons. In order to cut cost a builder will not replace cutting bits when they should. The bit gets shorter and the end product gets larger.
Either way makes for wildly varied parts sizes.
Or maybe the piston material has a greater expansion rate on some pistons.
A forged piston generally has a greator expansion rate than cast. Although now days it is not such a big problem.
 
They used various sized pistons selectively fit in the bores to compensate for manufacturing irregularities, as Jolly surmised.
Jeff
 
Thanks for clearing that up. I have wondered about that pretty much ever since I got the book. I had all kinds of crazy ideas, including expansion rates as jolly suggested. Turns out it isn't as exotic as I might have thought.
JC
 
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