magnum head bolts, reuseable? torque to yield type?
#2247373
02/04/17 09:22 PM
02/04/17 09:22 PM
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Joined: Nov 2003
Posts: 36,040 Lincoln Nebraska
RapidRobert
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Circle Track
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OP
Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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heads are off again for the coolant leak from Hell & are these bolts (MP) reuseable? they "look" OK but it is a racing app so I gotta confirm. thank you for your time.
live every 24 hour block of time like it's your last day on earth
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Re: magnum head bolts, reuseable? torque to yield type?
[Re: RapidRobert]
#2248128
02/05/17 11:35 PM
02/05/17 11:35 PM
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Joined: Oct 2003
Posts: 21,345 Marysville, O-H-I-O
70Cuda383
Too Many Posts
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Too Many Posts
Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
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Stock magnum 5.2/5.9 headbolts are not TTY and they can be reused. I've done it several times without issue
**Photobucket sucks**
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Re: magnum head bolts, reuseable? torque to yield type?
[Re: RapidRobert]
#2249061
02/07/17 01:30 PM
02/07/17 01:30 PM
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Joined: Jan 2005
Posts: 4,405 Michigan
MarkZ
Worthy
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Worthy
Joined: Jan 2005
Posts: 4,405
Michigan
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I've got a brand new set in a box if you're interested. R/T springs too.
1987 Fifth Avenue - 512/518/D60
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Re: magnum head bolts, reuseable? torque to yield type?
[Re: RapidRobert]
#2249095
02/07/17 02:26 PM
02/07/17 02:26 PM
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Joined: Jan 2003
Posts: 16,376
dogdays
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,376
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They're just regular bolts. Think of the torqueing directions...If it doesn't say torque to x lb ft and then y degrees after you hit the torque values, they are not torque to yield.
AND, although there is a lot of hysteria on this board about TTY bolts, the TTY bolts could probably be reused. You'd have to take a Materials Science course at Big Red to have it explained properly. But basically whatever stress is developed in the yielding would be the new elastic limit for the bolt, until you got noticeable necking down. As I have said many times, my Mercedes engine has TTY rod bolts and the FSM says they can be reused until the necked down portion reaches a minimum diameter. Of course, that was 40 years ago, but steel hasn't changed that much in that time.
What I'd be looking for in any torqueing situation is when you reach the torque value and the head keeps turning with no increase in the amount of pull you are putting on the torque wrench. This is for a non-TTY bolt. Most bolted joints are torqued to between 75 - 85% of yield. What I described above is yield, and if the bolt yields when it isn't supposed to there is a problem with the strength of the bolt either material or heat treat and it needs to be replaced.
And, if the FSM says replace the bolts do it. A set of bolts costs in the same range as a tank of gas. The designers know more than I do about that particular application.
R.
Last edited by dogdays; 02/07/17 02:27 PM.
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Re: magnum head bolts, reuseable? torque to yield type?
[Re: RapidRobert]
#2249243
02/07/17 07:09 PM
02/07/17 07:09 PM
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Joined: Sep 2007
Posts: 14,889 up yours
Supercuda
About to go away
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About to go away
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Posts: 14,889
up yours
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Back when I was changing Neon head gaskets the rule of thumb for reusing TTY head bolts was to lay a straightedge on the threads, if they all touched it was good to go, if not put in new ones.
They say there are no such thing as a stupid question. They say there is always the exception that proves the rule. Don't be the exception.
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Re: magnum head bolts, reuseable? torque to yield type?
[Re: RapidRobert]
#2249265
02/07/17 07:53 PM
02/07/17 07:53 PM
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Joined: Oct 2003
Posts: 21,345 Marysville, O-H-I-O
70Cuda383
Too Many Posts
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Too Many Posts
Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
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But again, magnum bolts are not TTY. All good points about TTY bolts, but for a magnum head on a magnum block, stock magnum head bolts can be reused.
**Photobucket sucks**
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Re: magnum head bolts, reuseable? torque to yield type?
[Re: 70Cuda383]
#2249301
02/07/17 08:46 PM
02/07/17 08:46 PM
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Joined: Nov 2003
Posts: 36,040 Lincoln Nebraska
RapidRobert
OP
Circle Track
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OP
Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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that's what I wanted (needed) to hear. I will reuse em & move on to other issues. thanks guys.
live every 24 hour block of time like it's your last day on earth
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