Head bolt re-torque
#1
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Head bolt re-torque
Well I Lost my head gasket yesterday after noon. But its back together now and running great. My question for you all knowing gods of Toyota. Is do I need to re torque my head bolts. If so when? How many miles? I have done a search and have found nothing. The FSM says nothing about re-torque either. The head bolts are new by the way.
#2
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On a 22re I think EB recommends it.
Quote from EB:
Quote from EB:
>>>*Other than simple overheat, the #1 cause of head gasket failure is clamping force variations.
Usually when I mention this, the answer is "I torqued it properly!"
*Yes, very likely, but torque, which is a twisting force, means almost nothing when we are talking about clamping force.
Dirt or machinery debris in the bolt holes will throw the clamping force off as much as 50% and more, even though the torque wrench reads perfectly normal.
The same happens when installing new bolts. The very best bolts made will show a rough mating surface at the threads when inspected under a microscope.
When installing new or used fastners, first be sure the bolt will spin in and out ALL THE WAY freely with simple finger pressure. Be sure they are lightly oiled, not too much which can hydraulic lock at the bottom of any blind holes and spoil your day.
Use this simple breakin procedure for any new bolts: Tighten all of them to 50%, back off 1/4 turn, then to 75%, back off 1/4 turn. Then take them to 100%, back off 1/4 turn and repeat. Do a retorque after full warmup.
*This procedure simply assures that the imperfections of the threads seat to the bolt hole threads.
Yes, time consuming, but much faster and less costly than another set of gaskets, the actual clamping force will increase vastly, even though the torque load is exactly the same.
The alternative is you may be additional twisting at the top of the bolt after the threads have come to a stop from excess friction.
If any single one does that, head gasket failure prematurely is gauranteed, plus it weakens the bolt....*EB
Usually when I mention this, the answer is "I torqued it properly!"
*Yes, very likely, but torque, which is a twisting force, means almost nothing when we are talking about clamping force.
Dirt or machinery debris in the bolt holes will throw the clamping force off as much as 50% and more, even though the torque wrench reads perfectly normal.
The same happens when installing new bolts. The very best bolts made will show a rough mating surface at the threads when inspected under a microscope.
When installing new or used fastners, first be sure the bolt will spin in and out ALL THE WAY freely with simple finger pressure. Be sure they are lightly oiled, not too much which can hydraulic lock at the bottom of any blind holes and spoil your day.
Use this simple breakin procedure for any new bolts: Tighten all of them to 50%, back off 1/4 turn, then to 75%, back off 1/4 turn. Then take them to 100%, back off 1/4 turn and repeat. Do a retorque after full warmup.
*This procedure simply assures that the imperfections of the threads seat to the bolt hole threads.
Yes, time consuming, but much faster and less costly than another set of gaskets, the actual clamping force will increase vastly, even though the torque load is exactly the same.
The alternative is you may be additional twisting at the top of the bolt after the threads have come to a stop from excess friction.
If any single one does that, head gasket failure prematurely is gauranteed, plus it weakens the bolt....*EB
#3
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Wow, great link...
This is also why I have a designated head bolt I sacrifice as a tap/thread chase.
Take one bolt and a disc grinder and just cut a groove or two around the bolt, straight up and down the threads. Just like a tap.
Now, don't lose that bolt, and you can use it with a dab of oil/WD40/etc and chase your threads the next time you're staring at the deck of a block.
I have one for a V6 and a 22R.
This is also why I have a designated head bolt I sacrifice as a tap/thread chase.
Take one bolt and a disc grinder and just cut a groove or two around the bolt, straight up and down the threads. Just like a tap.
Now, don't lose that bolt, and you can use it with a dab of oil/WD40/etc and chase your threads the next time you're staring at the deck of a block.
I have one for a V6 and a 22R.
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yep took 2 hours to tear apart. figure out what was needed. 1 hour to get parts...... 4hrs to install. I did clean my valves and straight edged the head and block. This truck is my daily driver so I had to get her rollin pronto. I would have loved to send the head to a shop but I had no time. Got to work tomorrow. Thanks for the info mt_goat! Think Ill re- torque my head bolts after work tomorrow and hope for the best.
Last edited by BrianJE; 09-06-2010 at 06:55 PM.
#6
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COUHGscepticalCOUGH, Man you are the man, took me 2 weeks. Due to a damaged fuel injector pintle, had to order set (4). My journey started with a broken spark plug in # 4 cyl. I stood there looking at it, (it was dang cold), saying to myself, I'm going to have to pull the head, Dang. PS I had been having a milky inside oil filler cap going on for a few weeks. So all was a blessing in disguise, the head was cracked. I am now a happy camper via a LCE head n SUPERBLEEDER pics, AMEN
#7
Did you have the head surfaced? I wouldn't have put it back on without.
As for re-torquing, I never have, and haven't had a problem. But my head went the machine shop.
As for re-torquing, I never have, and haven't had a problem. But my head went the machine shop.
yep took 2 hours to tear apart. figure out what was needed. 1 hour to get parts...... 4hrs to install. I did clean my valves and straight edged the head and block. This truck is my daily driver so I had to get her rollin pronto. I would have loved to send the head to a shop but I had no time. Got to work tomorrow. Thanks for the info mt_goat! Think Ill re- torque my head bolts after work tomorrow and hope for the best.
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I would have let a shop look at it but like I said before I had no time got to have it to get to work. I did put a straight edge on the block and head and found no warping.
Teuf I have worked on these little 4 bangers for years so I have ways to make it a quick fix. Hell this is my 9th Toyota truck LOL!
Teuf I have worked on these little 4 bangers for years so I have ways to make it a quick fix. Hell this is my 9th Toyota truck LOL!
#9
I would have let a shop look at it but like I said before I had no time got to have it to get to work. I did put a straight edge on the block and head and found no warping.
Teuf I have worked on these little 4 bangers for years so I have ways to make it a quick fix. Hell this is my 9th Toyota truck LOL!
Teuf I have worked on these little 4 bangers for years so I have ways to make it a quick fix. Hell this is my 9th Toyota truck LOL!
#10
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Brian I was yankin ya chain. I am sure that time frame is doable. Because YOU did it. I was just comparing it to my ADD attemt at doing the same thing. But I did it by golly.
#11
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As well, re-torquing headbolts (new ones) isn't a means of compensating for head warpage. The procedure is only for assuring an even clamping force against the gasket and to the deck. If the head's warped, even clamping force won't remedy that.
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