Exhaust Manifold Bolt Kit

[SanDiegoXJ]

Anyone know where I can get one that includes bolts/studs/dish shaped washers locally?

I don't have access to a junk yard, and I'm damn close to being able to start the Jeep back up and see what I broke this time. =( Was hoping Napa or Kragen would have a kit, but I don't see anything like the little dish washers anywhere. Gonna call the dealership tomorrow and hope for the best, but they never seem to have anything in stock around me.

 

[5-90]

Screws are threaded 3/8"-16, I think they're 1.75" long (check my site.)

I prefer to use bronze over carbon steel or CRES, for reasons I've given elsewhere. Check a local Fastenal.

While you're there, get a couple dozen Belleville Spring Washers in 3/8" - enough to put two under each screw head & stud nut. Nest one inside another, and put them under the screw head or nut so the open end is toward the manifold flange. Torque to spec.

 

[markw]

I've got extra bolts/washers over here if you are still looking for them.

 

[SanDiegoXJ]

Yep, I read a bunch of your other posts on using brass studs and loktite 242. I'd like to do that soon. My big concern was the washers since they are concave/convex. My assumption is that's to displace the pressure over a larger radius to prevent cracking and fatigue since little flat washers tend to buckle and only dissipate the pressure over a small area right on the edge.


And thanks Mark, but I was able to get some from a guy next to my work that has a MJ he's letting rot in a garage...sad, but at least I got my parts. =)

 

[5-90]

Yep, I read a bunch of your other posts on using brass studs and loktite 242. I'd like to do that soon. My big concern was the washers since they are concave/convex. My assumption is that's to displace the pressure over a larger radius to prevent cracking and fatigue since little flat washers tend to buckle and only dissipate the pressure over a small area right on the edge.


And thanks Mark, but I was able to get some from a guy next to my work that has a MJ he's letting rot in a garage...sad, but at least I got my parts. =)

277, not 242. 222/242/272 won't handle the exhaust heat, and will break down pretty much immediately.

Aluminum bronze or silicon bronze will be stronger than brass, even full hard Naval brass.

As far as the washers? Note that they're clamping, in several cases, an aluminum flange and an iron flange at the same time. Iron expands at 0.000006"/inch/*F, while aluminum expands at .0000012"/inch/*F. This creates an uneven tensile loading under the screw head, which can actually work to "unscrew" the screw. By allowing a spring washer to take up the slack, you reduce the effect of the differential loading under the head (still, check your manifold screws about once a year - you'll probably still find loose screws at the rear, under the manifold. It's common, especially on side-draught inline sixes.)

I've explained the science behind this in greater detail before, you should be able to find it with some light search work.