Quote:
Originally Posted by Laird Scooby
With most engines i've ever known with a cast iron block and alloy head, it's been necessary to renew the head bolts each time they're removed, due to designed in stretching. As far as i've always been aware, this is necessary to allow for different coefficients of linear thermal expansion which is why on engines with studs for the purpose of securing the head, the heads are cast iron, just like the block.
Yes and no, see above for a better explanation.
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Interesting. But I'm sure I've seen engines with alloy heads and traditional studs. * I remember inspecting a beautiful XK120 engine, with alloy heads and cleaming rows of chromed domed nuts. How does a length of threaded studding "know" whether it has a separate nut or an integral nut on the end?
If the point is that the head has to "slide" a bit to accommodate a differential expansion factor then I'd have thought that just needed a slightly larger hole to accommodate movement?
* My Triumph Mayflower had a steel block, traditional studs, and an alloy head (albeit sidevalve)