Fel Pro head bolt problem

[Landon427]

So I'm rebuilding my '99 2.5L engine; the head and block are flat and clean from the machine shop, and the bolt hole threads are ready to go. I put on a new Fel Pro gasket, put the head on using two guide dowels and insert new, lightly lubed Fel Pro head bolts. Start torquing them per FSM. On the last torque step, going from 40 to 110 ft-lbs, the 2nd bolt (middle, passenger side) feels 'soft' (force not increasing like 1st bolt did). Bolt breaks... Removed it. There's a spare bolt in the Fel Pro set so I figure why not try it, but that bolt also won't reach 110 (stops around 103 ft-lbs). I pull it out and it is obviously stretched. I stick a borescope down the hole and it looks fine. I try one of the used Mopar bolts I took out previously when dis-assembling the engine, and it torqued up to 110 just fine (I wasn't reusing the Mopar bolt set because one was painted, and FSM says that means the set had already been reused once). A friend came over and we compared torque wrenches on the harmonic balancer bolt at 80 ft-lbs and both seemed close to each other; mine was calibrated when purchased 2.5 years ago. I got the Fel Pro head bolts from Autozone; maybe they are counterfeit or maybe Fel Pro head bolts just suck. I guess I will try Mahle/Clevite head bolts... Rant off.

 

[Gilaguy23]

China junk, that is all. Kinda like the last set of leaf U bolts I bought from Quadrajunk. There was literally chunks of thread missing. Much the reason I gave up on vehicle resto/rehab work.

 

[macleanflood]

I used a set last year on a neighbor's 4.0. Zero issues.

I know the 4.0 needs thread sealant on some of the bolts towards the front.

Also need to clean and blow out the bolt holes...if they've got any liquid in them you can hydrolock a bolt hole.

-Mac

 

[mrblaine]

No fan of Fel Pro because cheap don't come good and good don't come cheap.

View attachment 623645

ARP Jeep 4.0L Inline 6Cyl Head Bolt Kit
$68.99
ARP High Performance Series Cylinder Head Bolt Kits

Cylinder Head Bolts, High Performance Series, Hex, Chromoly, Black Oxide, Washers, without Threaded Head Extensions, Jeep, 4.0L,

Summit Racing

https://www.summitracing.com/parts/...A1MkeiKBi3HOaCA1y7RMPHxwODfO-uLkaAhiVEALw_wcB

They make those for the 4 cyl he is working on?

 

[Old Jeepin Cowboy]

They make those for the 4 cyl he is working on?

My bad, I read it and then wife had some stuff for me to do and I forgot that is was a 4 cyl




Mahle GS33414 Cylinder Head Bolt Set
$44.79

 

[mrblaine]

My bad, I read it and then wife had some stuff for me to do and I forgot that is was a 4 cyl




Mahle GS33414 Cylinder Head Bolt Set
$44.79View attachment 623662

I was helping a guy with converting his front to the WU-08 locking hub conversion from Yukon. Mind you, he was converting from the WU-07 that I did my very best to talk him out of when he first thought about it.

He had some longer wheel stud requirements so I explained that we had explored and acquired all the common wheel stud solutions and they were fraught with one issue or another. As such, we strongly urge folks in his circumstance to do a little machine work ahead of time and that simplifies things greatly. Drill the rotor in a 5 on 5.5" bolt circle with clearance holes for 1/2" bolts. Match the pattern on the hub flange clocked over between the original holes, drill and tap them for 1/2-20.

Now you can use studs from 1.5" to 3" which are readily available and cheap for the rear axle shafts that are typically dual drilled for screw in wheel studs. And, should you need to do a future stud swap, no press is needed. Just pop the bearing hub and rotor off, impact out the damaged stud, impact in a new one with some Loctite, good to go with minimal effort.

Bit later he comes back with- "Oh, you were wrong about there not being any longer press in studs. We found these from ARP and they work perfectly with some minor drilling" He sent a link. 50 bucks for 4 studs, need 3 paks so you have enough and a couple of spares.

I explained that I never said they didn't exist, I just don't see the value in 14 dollar each wheel studs when the other method lets you use multiple lengths at 2-3 bucks each. He was more interested in proving me wrong that doing something that makes sense.