Jan,
You are a brave soul, and I wish you luck building engines.
All bolts stretch as a function of load, mostly determined
by the diameter, not the material. Modulous of elastisity
governs the stretch rate, and with most common steels this doesnt
vary too much. Yeild and shear strengths are very material
dependant, which is why more exotic materials can be stretched
further before the yeild is exceeded, and the fastener fails.
The sunbeam head bolts are not magic, they are 3/8 24 automotive
bolt/studs. they were made 30+ years ago, and torqued/loosened
many times most likely.
You can purchase new bolts from any supplier that sells AN type
hardware.
Aircraft Spruce is one that is on the internet than will sell
you AN hardware, just learn how to spec an AN fastener before hand
because the length spec is different on the AN hardware.
They have the right length in stock, I checked a few months ago.
The will cost about $4 each, less in qty.
Use good thick HARDENED washers underneath, and through away the
rootes washers, they are junk.
Although AN fastener will be better than the stock bolts, I would
ONLY use them in a stock engine with the stock torque setting as
AN fasteners are designed for high shear strength not yeild.
Jarrid gross
-----Original Message-----
From: owner-alpines@autox.team.net
[mailto:owner-alpines@autox.team.net]On Behalf Of jumpin'jan
Sent: Friday, August 24, 2001 6:06 PM
To: Alpine List
Subject: Re: Question: head bolts
Matthew,
I wouldn't replace the head bolts at all. They are very specially made.
Keep them! However, in today's engines it's a different story because
they are designed to stretch and need to be replaced after each head
gasket replacement.
Jan
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