Over the past few days, I've been putting my newly rebuilt heads back on my 170K shortblock. A couple of exhaust studs on the pass. side were broken when I pulled the heads, so I had them drilled out/helicoiled while they were at the shop and I installed some new studs. The drivers side studs were unbroken and appeared to be fine.

Well, I got both heads torqued on and began to install the drivers side manifold. Snugged five of the six nuts and then felt the sixth one start to give. We're talking barely twisting a short 3/8 rachet, about five foot pounds. Sure enough, the stud broke, no way to extract it with the head installed, so I had to pull it back off and take it to the machine shop. They were able to put it on their mill and perfectly drill it out, no helicoil needed.

Anyway, the point of this message is, do like I did before I reinstalled it... Slap the manifold on the head and torque down the nuts before wasting a $25 Victor head gasket!

I've got my mechanic mojo back and building up steam! Having fun putting this thing back together. Been sitting for five months now.

Nothing better than enjoying a tasty IPA while torqueing down your shiney, rebuilt heads!!!

So maybe the thing to do is replace the studs with the rest of the head work. I'm planning on doing mine soon, so I'll be thinking of this/you. Thanks!

Mmmmmm, IPA!!! <img src="/forums/images/graemlins/cheers.gif" alt="" />

Absolutely it is. IMO, any engine rebuild is suspect without replacing all exhaust studs/bolts, including those on the manifold flanges, heat shields and the EGR valve and pipe. The ones in aluminum heads are not fun to remove, though. <img src="/forums/images/graemlins/barf.gif" alt="" />

Frank

Mine didn't break but the two studs have backed out.

That same thing has happened to me...break off a stud in the most inconvenient place...Thats why I love aluminum heads though. All I do is pull the manifold back off and weld a nut to the broken off stud with a small mig welder, sometimes it takes a few tries but I have always gotten them out. It just makes a bolt out of the broken stud and just take a ratchet and thread it out.

Unfortunately, my luck seems to always leave me with a stud broken off flush with the gasket surface or even below it. The weld trick won't work on those.

I thought about replacing all the studs. But they are a b***h to get out, and I broke one trying on the other head. So, I risked it, and paid for it. Its all back together now, just gotta finish the intake and injector install, timing belt, and I'll be ripping the Mitsu again!

Hey I'm back(been out of town). I want to add to this topic of ex manifold's the importance of stess releiving. And I can't understand why Mitsu didn't design them this way.
Anyway when I pulled the engine from the frame I had a nice exhaust leak from number 4 cylinder leaving black crude dripping down the engine. Funny there was no audible indication though.
The only solution I have found to this is to cut the webs in between ports on my new manifold.
I haven't even looked at the studs to see if they pulled out <img src="/forums/images/graemlins/scared.gif" alt="" />

That's why I recommend cutting the webs. I even stress relieve the manifold by baking it in the oven at 500 for 12-20 hours, then a long cool down, THEN cut the webs and have the gasket surface faced back flat.

There's a stud welder made for MIGs that has a hollow stud for the mig wire to feed thru. Just put the stud on the gun, zap it to the broken stud, and you have about 75% of the original strength back. Muffler shops love 'em....

Isopropyl alcohol ??? <img src="/forums/images/graemlins/confused.gif" alt="" />