O RLY?!

My experience drilling out broken studs and bolts has been absolutely horrific. I was dreading this task because the last time I failed, I had to replace the cylinder head.

I had an exhaust leak at the passenger side manifold that was causing the car to sound like a go-kart when it accelerated.  I tried to tighten the nuts on the studs and discovered they were broken.  I went ahead and removed the manifold and discovered a total of three broken studs out of six.

One of the studs was broken off above the hole and I was able to grab it with some vice-grips and twist it out.

The other two were broken below the hole and would require drilling to remove.

The angle was horrible and there was very little clearance to get a drill in there (even with a right-angle attachment).

I ordered a special tool that helped assist me in centering the hole and drilling straight.

It has a threaded insert that is the exact same size as the stud.  There is a drill bit right down the center.  Since the stud was broken below the surface, I could use this guide to grab one or two threads and position the drill directly center and at the correct angle.  This made the task so much easier.

After drilling the hole, I used a screw extractor to twist out the remainder of the stud.

One other thing I learned through this process.  Cobalt drill bits cut through steel like butter.  I finally broke down and dropped a bunch of money on a nice drill bit set.  What a difference!  This also made the job significantly easier.

While I was waiting for some parts to come in, I pulled the turbo off for a rebuild and cleaned everything up.  I reinstalled the turbo, the rest of the intake, timing belt, and distributor.  Cranked the car a few times to get the oil circulated and then fired it up.

Got the idle set properly and then set the timing to about 15 degrees BTDC.  The car is running well now.  I think the air flow meter occasionally gives out, but its only happened once since I started driving the car again, so I haven’t looked into replacing it yet.

The car hits boost pretty quickly and is noticeably faster.  I’m still running stock boost (6.8psi), and I upgraded to 93 octane to avoid any knocking.  I have  a boost controller, but I figure I’ll run stock for a while before I attempt to adjust it.  I also may need an intercooler in order to increase the boost safely.

I purchased a re-manufactured cylinder head for $180 plus core.  I bought a new head gasket, new intake manifold gaskets, and new valve cover gasket from the dealer. I couldn’t get the intake studs out of the old head, so I bought some new studs too. Then I mangled the cam shaft seal while removing it, so I ordered a new one of those too.

The new head is on and torqued down per the Haynes manual (5 step process). I left the exhaust manifold in the car and then slid it on over the studs after attaching the new head. I couldn’t figure out how to get the manifold+turbo out of the engine compartment even with the head removed from the block. The head+manifold+turbo probably would’ve been too heavy for me to install solo anyway.

Waiting on some studs and the cam seal right now.

I broke an exhaust stud when I was removing the exhaust manifold.  I read up on how to extract the stud and decided I would try it.  I spent a couple days reading about it and talking to people to get myself all psyched up. . . and I failed.   I could not get the remains extracted with an extractor, so the next step was to drill the same size hole and re-tap the threads. The cylinder head is made of aluminum, so it’s relatively soft, and I either drilled to far, or I was slightly off center, because a cooling passage was compromised.  After running the engine for a few minutes, I started losing coolant out of the valve cover.  Not good.

Only fix is to replace the head.  Remanufactured cylinder heads for this engine are fairly common (it was used in the Maximas through the 90s), so it was easy to find a supplier.

Got the engine out toady.  I’m still in disbelief that we were able to do it, but I will be even more amazed when we get it back into the car.