Loosening rod bolts

General engine tech -- Drag Racing to Circle Track

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Roundybout
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Re: Loosening rod bolts

Post by Roundybout » Wed Feb 07, 2018 10:16 pm

So is running a fastener to 15-25lb/ft depending on fastener size to burnish in the threads a couple of times ok? I use whatever recommended lube and do that before final assembly once maybe twice.

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modok
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Re: Loosening rod bolts

Post by modok » Thu Feb 08, 2018 12:46 am

I don't think there is any ONE way that is best for all.
If you are getting consistent results then it's working. If not, try something else.
You can go by torque, stretch, AND degrees it took to get to torque.
Keep an open mind and hopefully you will see when something is different than it should be.
Glen Urban

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Re: Loosening rod bolts

Post by tresi » Sun Feb 11, 2018 3:25 pm

hoodeng wrote:
Sat Feb 03, 2018 2:02 am
Fuel motors nearly know their own way back together!! they are assembled every time with torque wrenches and procedure , a lot of critical fasteners will have a designated amount of cycles ,also the fasteners are all high end products.I wouldn't want to be the crew member responsible for a given task, stripping or breaking a fastener and causing a rush no one wants or expects [no beer for him that night]

Cracking fasteners loose on any production engine for overhaul as has been stated by others before can give important information by feel ,all fasteners in a given type of assembly i would expect to crack off or release in pretty much the same manner .Any hanging up or doughy feel needs to be investigated ,for me anything like what i have described would see a change of fastener on reassembly, after they are cracked loose or released and backed off a turn or two a rattle gun set on minimum torque will speed things up a bit, and you can still monitor the speed and sound it back off at in case something tightens up.

Cheers.
If you seen the post 1 st run tear down facebook live post from the CatSpot top fuel dragster you can catch a glimsp of the rod bolts being loosened with a rattlegun. Granted such a rod only has a 1-4 run lifespan.

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