Misfire!
It's been a while since I've changed anything too major. Most work has been oil changes, etc. since doing my clutch for the second time last year (due to a leaking crankshaft seal).
About a month ago, while driving to work my CEL came on indicating a cylinder 4 misfire. Took a look around that weekend and thought maybe I was leaking oil from a poorly seated valve seal. Hooked up the air compressor to take off the valve springs and air rushed out the exhaust manifold. The cylinder simply couldn't maintain pressure like the other cylinders.
At this point, I realized I will have to venture into my engine further than I ever had before. Time to take the cylinder head off...
It was immediately clear that something different was going on in cylinder 4:
When I flipped over the head, it was obvious why she was misfiring and why I couldn't pressurize cylinder 4:
Since the head was off the car, this was a chance to fix the exhaust stud that I broke off when changing exhaust manifolds. I temporarily filled it with some fake metal filler:
In order to rethread the hole for the correct threads, I got a Time-Sert thread repair kit and threw the head on my drill press:
I used the old manifold as a template to make sure I drilled in the right place. In the end, it shook quite a bit on the drill press so the hole was a bit too large for the standard sized Time-Serts. Thankfully, they have larger inserts for repairing holes that were already repaired. After the head came back from the machine shop, I fixed the threads with a bigger insert:
Given that this is not "routine" maintenance, I picked up a complete set of new valves. Dropped them off with new valve seals at the machine shop and I got back essentially a new head...so pretty!!...
Since I needed a new intake gasket anyway, I picked up a Bisimoto thermal gasket instead of OEM (also got extended SS studs from King Motorsports):
Also got Unorthodox underdrive pulleys while I had the pulley off:
While waiting for the next weekend to arrive (so I could install the cylinder head and finish the job), I sanded the lettering on my newly painted valve cover:
And since I didn't want all the new parts to be related to the problem, I picked up some "fun" ones, too...a set of Corsport shift cable bushings:
I wasn't planning on an obvious difference since I already have the PSPEC shifter. The difference with the bushings is night and day...
In the end, I did get her back together. It took some time but it was worth it in the end. It did take a while for the idle to steady as the coolant was completely drained from the system. The idle fluctuated a good bit until the day after the initial test drive.
The list of all parts replaced is more significant than for any other job I've done:
- New valves and valve seals
- Valve job and resurfacing
- Head gasket
- VTEC O-Ring
- IACV O-Ring
- Water valve
- Radiator hoses (ALL; including the small "bypass" hoses)
- Heater hoses
- Thermostat
- Front balance shaft seal
- Camshaft seal
- Crankshaft seal
- Time-Sert repaired exhaust stud threaded hole
- Bisimoto Thermal Intake Gasket (Upgrade)
- Unorthodox Underdrive Pulley Set (Upgrade)
- Corsport Shift Cable Bushings (Upgrade)