Why New Head Bolds?
Thread Starter
TECH Veteran
Joined: Aug 2002
Posts: 4,055
Likes: 1
From: Hartsdale, NY
Why New Head Bolds? I've been re-using factory engine and transmission bolts for years, ...Now I understand that GM engineered their Gen III engines (LS1-LS6) so you need to buy new bolts when re-assembling these engines.
Is this a bad joke to get us to buy new bolts from GM? I fell for the joke and bought the new bolts for a head and cam swap but believe there is no reason to replace the existing factory bolts.
Anyone re-using factory bolts out there?
Is this a bad joke to get us to buy new bolts from GM? I fell for the joke and bought the new bolts for a head and cam swap but believe there is no reason to replace the existing factory bolts.
Anyone re-using factory bolts out there?
TECH Addict
Joined: Dec 2001
Posts: 2,298
Likes: 2
From: new england
Re: Why New Head Bolds? This is no joke, the bolts are torque to yield bolts or stretch bolts.They were designed in my opinion to dismiss the need to retorque fasteners after components and gaskets had thermally settled from use.Its not that bad of an idea but it makes for a pain in the *** for us when playing around with motor setups.Switch to studs to get best clamp loading with no wear and tear on block threads with aluminum blocks.
Re: Why New Head Bolds? You always want to use new hardware, even with the standard SBCs. Whenever you stretch a bolt (by torqueing it to the required value) and cycle it, it wears out (fatiges). So when you go to reuse it, the torque values must be refigured to provide the same clamping force. It is a dumb idea IMHO to reuse factory bolts. One is they are toast, second is they are not as good as the performance aftermakets (such as ARP). Best bet is to use studs if you are playing around with different setups. Be warned, studs even wear out, but they have a higher tensile strength than bolts.
Oh btw, this belongs in the Internal forum (moderators!). <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
<small>[ August 29, 2002, 07:38 PM: Message edited by: MRZ28HO ]</small>
Oh btw, this belongs in the Internal forum (moderators!). <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
<small>[ August 29, 2002, 07:38 PM: Message edited by: MRZ28HO ]</small>
