Possible problem torquing heads??
Thread Starter
Instructor
Joined: Nov 2008
Posts: 235
Likes: 9
Possible problem torquing heads??
Hey guys, I was installing heads/cam tonight and everything went smoothly. The only thing that happened that concerned me is while torquing the heads I torqued all head bolts in order to 22lb/ft and then went thru and turned them all 90 degrees. then went through and torqued 1-8 another 90 degrees.
Then went I went to do the last two (9 and 10) to 50 degrees. Well the problem is, I was used to turning the bolt 90 degrees after doing so many, so instead of turning the first one 50 degrees, I probably turned it closer to 75-80 degrees. The rest I got turned to about 50 degrees, but that one is about 25 degrees too far. I just left that one that tight because I know that once I loosen it that bolt is ruined and I need a new one.
My question is, is this going to cause any problems? Are there any chances that I maybe damaged the threads or damaged something by going too tight with it??
Then went I went to do the last two (9 and 10) to 50 degrees. Well the problem is, I was used to turning the bolt 90 degrees after doing so many, so instead of turning the first one 50 degrees, I probably turned it closer to 75-80 degrees. The rest I got turned to about 50 degrees, but that one is about 25 degrees too far. I just left that one that tight because I know that once I loosen it that bolt is ruined and I need a new one.
My question is, is this going to cause any problems? Are there any chances that I maybe damaged the threads or damaged something by going too tight with it??
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
Without knowing specifics of how the bolt is designed (material, etc.) and where it is on its load curve it would be hard to say exactly where you stand. However, if you used a GM gasket (pretty forgiving) I would finish assembly and leave the bolt alone unless you have an issue later. I wouldn't think it would lose preload from what you did. Just keep an eye on it.
Good luck.
Good luck.
Thread Starter
Instructor
Joined: Nov 2008
Posts: 235
Likes: 9
Without knowing specifics of how the bolt is designed (material, etc.) and where it is on its load curve it would be hard to say exactly where you stand. However, if you used a GM gasket (pretty forgiving) I would finish assembly and leave the bolt alone unless you have an issue later. I wouldn't think it would lose preload from what you did. Just keep an eye on it.
Good luck.
Good luck.
Thx
Melting Slicks
Joined: Dec 2003
Posts: 3,315
Likes: 17
From: Near Jacksonville Fl.
Actually they are torque to yield bolts so what you have done over torqued and stretched the bolt so I would remove it and start over with a new bolt.
You may have lost clamp load when the bolt stretched so why take a chance?
You may have lost clamp load when the bolt stretched so why take a chance?
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Drifting
Joined: Mar 2011
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From: East Aurora NY
Melting Slicks
Joined: Nov 2008
Posts: 2,938
Likes: 65
From: Rochester Hills MI
Either replace all the bolts or leave it alone. If you try to replace the single bolt, the the torque pattern will be thrown off completely. Since you already stretched the other bolts, they would have to be replaced to get the proper sequence again. IMO, the torque pattern is more important than being off 30 degrees on 1 bolt.
If the bolt did not break, you should be fine. The bolt will most likely break before it strips the threads out. Because it is a torque to yeild application, the force that the threads in the block can hold should be higher than the ultimate strength of the bolt by design. This is why I always use factory bolts for torque to yeild applications. You never know if aftermarket bolts have the proper safety factor. Although, I'm not sure which one you would consider more of a pain - stripping the threads or having a bolt broken off in the block
If the bolt did not break, you should be fine. The bolt will most likely break before it strips the threads out. Because it is a torque to yeild application, the force that the threads in the block can hold should be higher than the ultimate strength of the bolt by design. This is why I always use factory bolts for torque to yeild applications. You never know if aftermarket bolts have the proper safety factor. Although, I'm not sure which one you would consider more of a pain - stripping the threads or having a bolt broken off in the block
Drifting
Joined: Mar 2010
Posts: 1,628
Likes: 15
From: Seattle WA
Yes. The TTY bolts actually stretch when you torque them, so to back them off again would mean you're essentially removing that bolt so far as clamping forces are concerned.
