... Aluminum expands at about twice the rate of steel, and if these were two abutted 12 inch solid billets of both metals, you could expect the difference between the two at 220 degrees to be about .020 [inch]...
I figure closer to about .012" (if "matched" @ 60` F, raised to 220` F). Or were you planning to do the build at 0` F?
Well, this is the calculator I pulled up -
http://www.engineeringtoolbox.com/linear-thermal-expansion-d_1379.htmlI figured 70 to 220 and subtracted to come up with the difference. If I assembled this in the garage in January, 0 degrees is a possibility, but I try to do the assembly in the house - it keeps my beer from freezing.
I guess the question is - given that neither is a solid bar, that the pieces would be clamped around the perimeter, and if the steel piece were cut as Rex suggested, would the rate of expansion between the steel and the aluminum create more problems than the stock piece?
My thought is that the steel - growing less and at a slower rate - would constrain the aluminum pieces secured to it, but would such constraint adversely effect the bearings, which are secured in the aluminum? I don't know.
So here's a couple of questions that all this poses - let's start with this tidbit, which I posted up earlier -
"According to the Land Rover service bulletin that covers the new MLS gasket, the new oil rail MUST be fitted at the same time as the replacement gasket . . ."This is with regard to the stock bolts, but it raises a question - Is it because of the wear on the threads that the oil rail needs to be replaced, or because of the tension put upon the ladder? If I go with the ARP studs, and the threads are not removed from the oil ladder, will this piece - at 50 ft/lbs - survive multiple disassembles?
Once again, I'll be right up against the limit of the "I" engine class, and while we may be able to pump it for displacement - provided I make impound. With the studs, will I need to tear the bottom end off as well and replace the ladder after inspection? Is the instability a result of the ladder being deformed, or is it a case of the threads in the ladder deforming? If it's the threads that are being deformed, will the use of studs rather than bolts diminish the problem?
The studs would go in once - Bolts would wear the threads in the ladder every time you replaced them.
So is it the wear of the
threads in the ladder that is the concern, or is it the clamping pressure on the oil ladder that has led to the issue of poor clamping in the kettle?