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 Head Bolts Replace or Not?
#1101455
06/05/16 08:08 PM
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Joined: Mar 2005
Posts: 1,006
OP
Body Damage is Cool
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So I had a bit of a setback. Did not have my air pressure fully connected and dropped a valve in the cylinder doing valve seals.
I have removed the DS head to retrieve the valve. FSM does not mention replacing head bolts.
Is it necessary to install new head bolts rather than using old ones?
Thanks
92 Montero LS 3.0L V6 Auto, Stock, Original owner, 185,800K miles
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Re: Head Bolts Replace or Not?
[Re: pcc]
#1101456
06/05/16 08:16 PM
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Joined: Mar 2005
Posts: 1,006
OP
Body Damage is Cool
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OK, I answered my own question. FSM does not say replace, Haynes says just replace in same position.
I think I'll reuse.
92 Montero LS 3.0L V6 Auto, Stock, Original owner, 185,800K miles
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Re: Head Bolts Replace or Not?
[Re: pcc]
#1101459
06/06/16 04:15 AM
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Joined: Feb 2000
Posts: 6,247
Trail Leader
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Easy answer... I would suggest that you run a tap through the bolt holes and clean the bolt threads with a die or wire brush.
I have a personal belief that when torque specs are involved, I want to work with clean thread connections.
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Re: Head Bolts Replace or Not?
[Re: pcc]
#1101461
06/06/16 05:06 AM
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Joined: Feb 2005
Posts: 7,458
Trail Leader
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Also, the V6 headbolt holes are blind. It has long been advised on this board to measure the length of the bolt to be used and compare that to the sum of the hole depth plus the gasket thickness plus the head thickness. If the bolt bottoms out, then you may achieve a false torque reading.
1987 Raider - Roxy
1988 Mighty Max 2.6L Turbo - Pearl
1997 Mountaineer V8 - Freddy
2000 Excursion V10 - Freya
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Re: Head Bolts Replace or Not?
[Re: rxinhed]
#1101464
06/06/16 02:28 PM
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Joined: Dec 2007
Posts: 2,348
Body Damage is Cool
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Also, the V6 headbolt holes are blind. It has long been advised on this board to measure the length of the bolt to be used and compare that to the sum of the hole depth plus the gasket thickness plus the head thickness. If the bolt bottoms out, then you may achieve a false torque reading.
Extremely important if'n you get new head bolts.
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Re: Head Bolts Replace or Not?
[Re: pcc]
#1101465
06/06/16 04:18 PM
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Joined: Mar 2005
Posts: 1,006
OP
Body Damage is Cool
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Thanks all for the input. I will clean the threads and measure the length but not run a tap.
I did run a tap on the rocker arm bolts from suggestions 10 years ago but was not happy with the looseness of the fit, although they have held. I believe the head bolt threads are a much tighter tolerance fit than over-the-counter taps (75%). I am afraid of loosing too much thread surface with a tap.
92 Montero LS 3.0L V6 Auto, Stock, Original owner, 185,800K miles
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Re: Head Bolts Replace or Not?
[Re: pcc]
#1101489
06/10/16 09:50 PM
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Joined: Jan 2001
Posts: 13,649
Web Wheeler
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You want a thread chaser, not a tap.
Not responsible for advice not taken...
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Re: Head Bolts Replace or Not?
[Re: fasteddy]
#1101490
06/10/16 10:24 PM
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Joined: Mar 2005
Posts: 1,006
OP
Body Damage is Cool
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Actually the bolts had little to no resistance. I was easily able to hand screw them even without oil. I have torqued them and everything went fine.
I checked length and had about 1/2" extra clearance over bolt length.
Hopefully Sunday start.
92 Montero LS 3.0L V6 Auto, Stock, Original owner, 185,800K miles
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