The D16z6 in my RT Wagon crapped on me earlier this year, and the D15b2 in my sedan just crapped as well, so I'm scrambling to get an engine working so I can get to and from work.

First of all, here's what happened to the sedan (D15b2). I got snowed in at my buddy's house last week so when I finally got the chance to leave, I started the car, let it get to full operating temp, then headed out. About 10 miles down the highway, my power dropped and it started firing on 3 cylinders only. I pulled over, checked my plug wires (still getting spark) but it was cold as *****, so I just decided to limp it home.

SIDE NOTE: The motor that was in the car when I bought it had the same problem, and the previous owner said it was a "burnt valve" (whatever that means).

I got the car home and pulled the plug wires, and the spark plug well on one of the cylinders was FILLED with oil (I'm talking 3" of oil). I soaked up as much as I could and pulled the plugs. The one from the bad cylinder was soaked in oil but the gap was huge (about 1/8") and the other three were pretty white and also had large gaps.

So after swapping out the cap and rotor with a known good one and changing out the plugs and plug wires, it still was running on 3 cylinders so I assumed it was a valve problem.

At this time I was going to pull the head of this motor and the original b2 that was in the car before and see if I can figure out what's going on and scavenge parts between the two to make a decent working head.

Any thoughts on what the cause could be?

Now I also purchased a head gasket kit and water pump/timing belt kit for a spare z6 that I picked up a while ago for my wagon. The motor had been raped pretty bad and I'm going a bit further with that one because I want it to run well for a while. I plan on deglazing/honing the cylinders and replacing the rings on that one.

While I'm that far into the motor, are there any other things you guys would recommend doing to it?


Thanks for the input.

 

If the spark plug well was full of oil
That shows signs of bad valve cover gaskets.
That may be the reason you're running on 3 cylinders. Too much oil on 1 plug not allowing spark to flow from wire to plug.

I would first determine why the engine runs poorly.
A rebuild mostly comes from engine compression being lost.
If runnin on 3 cylinders only, probably bad valve seats, on that 1 cylinder

But if you going to completely over haul it,
Re hone the walls, get new rings. Do the correct ring break in procedure
Can't strew that that enough, that will determine if the walls last another 200k miles or another 200 miles.
Only turn the car on when it's all ready for break in.
Resurface head.
Get a 3pt valve job.
Use fel pro or oem head gasket. I recommend mls gasket only

New gaskets..-
VC. Oil pan. Water pump. Rear and front main seals. Cam seals.
Exhaust and IM gaskets too.