Slipping head bolts... better solution?
#11
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5 pounds is - don't be offended, crazy
As pointed out 3 steps is just fine
What you are really looking for in a torque spec is the clamp load that is a result of the thread pitch and the torque applied. With enough load the bolt stretches a bit to maintain tension until you stretch it so much it is permanently elongated..
Lubricant and the type of lube on the threads will change everything.
I don't remember ever being concerned about the washer spinning but a little googling brought me to an article that explains it. I learn something new every day
Regardless when torqueing it is important that you reach your number while the fastener is turning. The amount of torque to get it moving is way more than the moving torque. Actually we used to loosen the bolt/fastener 1/2 a turn and then in one smooth movement go to the required number.
As pointed out 3 steps is just fine
What you are really looking for in a torque spec is the clamp load that is a result of the thread pitch and the torque applied. With enough load the bolt stretches a bit to maintain tension until you stretch it so much it is permanently elongated..
Lubricant and the type of lube on the threads will change everything.
I don't remember ever being concerned about the washer spinning but a little googling brought me to an article that explains it. I learn something new every day
Regardless when torqueing it is important that you reach your number while the fastener is turning. The amount of torque to get it moving is way more than the moving torque. Actually we used to loosen the bolt/fastener 1/2 a turn and then in one smooth movement go to the required number.
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Marc
www.mercruiserparts.com
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Marc
www.mercruiserparts.com
www.go-fast.com
www.bammarine.com
www.cyborgtransmissions.com
It's not alive -www.BoatStuffExpress.com - temporarily retired
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14 apache (03-22-2021), mike tkach (03-19-2021), OLDRAT (03-19-2021), resurrected (03-19-2021), SB (03-18-2021), sonicss42 (03-20-2021)
#12
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No offense taken at all Marc. And you’re right, it is crazy. That only started when the washer slipped and I was concerned about busting a bolt.
I read about the washer slipping issue via Engine Labs when I had issues with the other one. I ended up buying a new bolt set for that one.
Perhaps not enough lubricant between bolt/shoulder and the washer? I’ll back them off tomorrow and see if the washers have any witness marks.
Puzzling. This is the first engine build where I’ve had an issue like this.
I read about the washer slipping issue via Engine Labs when I had issues with the other one. I ended up buying a new bolt set for that one.
Perhaps not enough lubricant between bolt/shoulder and the washer? I’ll back them off tomorrow and see if the washers have any witness marks.
Puzzling. This is the first engine build where I’ve had an issue like this.
#14
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My machinist did a great job cleaning everything up, but I also subscribe to the idea of “trust but verify.” I ran taps through every bolt hole as soon as I had the block on the stand.
What I probably have here is some contamination of the surface where the washer meets the head. I’ll need to pull the offenders and look. That’s the only thing I can come up with.
Question... how much lubricant are you guys using when installing head bolts? I’ve tried to keep it from being excessive. I use a brush to get a nice film but without having it oozing everywhere during assembly.
What I probably have here is some contamination of the surface where the washer meets the head. I’ll need to pull the offenders and look. That’s the only thing I can come up with.
Question... how much lubricant are you guys using when installing head bolts? I’ve tried to keep it from being excessive. I use a brush to get a nice film but without having it oozing everywhere during assembly.
Last edited by TomZ; 03-19-2021 at 08:53 AM.
#18
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For the rest of us, us an article on the head bolt washer turning issue:
https://www.enginelabs.com/engine-te...ng-head-bolts/
So, after reading that article, my question to ARP, since you are ‘the best’ and charge accordingly, why don’t you machine the washers this way now ?
https://www.enginelabs.com/engine-te...ng-head-bolts/
So, after reading that article, my question to ARP, since you are ‘the best’ and charge accordingly, why don’t you machine the washers this way now ?
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#19
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Yep, I’m using washers from ARP that came with the bolts and they’re installed correctly. I’ve used them plenty of times before now. This is the first time they’ve been a problem.
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