A few months back, there was a discussion that included engine rod bolts
and a few comments/suggestions were made about obtaining the bolts from
a local supplier at a lower cost than what it would from one of the big
3 parts suppliers.
Today I went to an "old fashioned" hardware store and indeed they have
grade 8 bolts of the same size. I noted one difference, however,
between the factory bolts and the potential new replacement: the shank
of the original bolt narrows a bit starting about 1/4 inch below the hex
head while the candidate replacement is the same diameter all the way
through the threaded area. The diameters just below the hex head are
the same. The new bolt fits OK, however.
I discussed this difference with the machinist currently working my
block and he could only think that the narrower portion of the factory
bolts would cause them to "stretch" upon torquing while the replacements
may not do so as easily. He determined that they should be OK.
I'm curious as to what everyone thinks. Why did our British Cousins do
this? It's a big cost difference, 55 cents each vice $5.25 each!
'75 TR6 Undergoing a Rehab