So I took apart my engine today...

Crazy_pilot · #1 08-05-2010, 06:12 PM

What the hell did they make this car out of? I pulled the engine out of the car yesterday and took the heads off today. Through the whole affair I only broke a single bolt, and that was just one of the little 10mm guys holding the transmission cooler line to the bottom of the left head. The header/pre-cat nuts came off easily with the impact, the head/manifold nuts/studs came out easily, the engine and trans separated under their own weight... I've broken bolts in 5 year old cars, yet my 18 year old one came through easily.

Once I had the heads off I noticed something a bit odd though. Cylinders 1-4 are quite clean. Some carbon buildup but not really much. # 5 and 6, however, were a different story. Tons of carbon buildup, and actually softer deposits (as opposed to #1-4 which were very dry, hard deposits). The rear left cylinder (#6?) was missing for sure, the wires going into the coil are fried.

Thoughts?

Cam · #2 08-05-2010, 07:42 PM

Was the headgasket intact? Where were the deposits? On the combustion surface of the pistons?

Crazy_pilot · #3 08-05-2010, 08:37 PM

The gaskets were intact with no super obvious signs of leakage. The deposits were on the surface of the piston, the ridge of the cylinder that the piston doesn't touch, and very heavy on the cylinder head/valves. There are spots on one of the exhaust valves were you can see it was pinging, burning pits into the deposits.

The gaskets hadn't totally failed. I believe I was getting some combustion gases forced into the coolant (the upper rad hose was always rock hard after a drive. My PWR rad has a cap with a pressure release lever and even after a 15 minute drive there was a large amount of air in the system that would bleed out.) I was also consistently finding trace amounts of oil in the coolant. Plus coolant slowly vanishing, the occasional temp spike...

Cam · #4 08-05-2010, 08:45 PM

So, are you going to finish your teardown or are you gonna stop here and do a reseal?

Crazy_pilot · #5 08-05-2010, 09:06 PM

Head gaskets and reseal are all I have time (and realistically, money - just paid my tuition and heading back to school in a month) for. I had wanted to get into it and replace the bearings, rings, etc but it's too late in the summer for all that work now. Oh, and I'm making new pre-cat pipes. That'll be a different thread. Or a continuation of my other exhaust thread.

Manarius · #6 08-05-2010, 09:06 PM

If the EG33 is like the EJ22 when it comes to the fuel rails, #6 would be running lean most of the time (since it's last in line for fuel), so that may be where the deposits come from.

Cam · #7 08-05-2010, 09:33 PM

That last post makes sense to me, but I have no actual experience with that. I did not notice any inconsistencies when I did my tear down...but I knew everything was getting scrapped save the block and crank and rods, so that was not really a concern of mine.

A reseal is all you should really need to do. Unless you have had a bearing failure, or you have bottom end noise, I do not think that you will have any immediate troubles. If you break it down any further, you will need machine work and things will get extremely expensive, and quickly. Get her as clean as you can before you put her back together.

Good luck with your reseal. Take pictures and share

Crazy_pilot · #8 08-06-2010, 07:29 AM

From reading on NASIOC built STi's commonly have cylinder #4 fail (ring lands mostly), although I have yet to see someone present a definitive reason. Many blame an overlean fuel mixture, for the reasons you suggested Jason.

I'll get some picture on Monday when I'm back at the shop.

Manarius · #9 08-07-2010, 10:02 PM

Quote:

Originally Posted by Crazy_pilot

From reading on NASIOC built STi's commonly have cylinder #4 fail (ring lands mostly), although I have yet to see someone present a definitive reason. Many blame an overlean fuel mixture, for the reasons you suggested Jason.

I'll get some picture on Monday when I'm back at the shop.

In the EJ22, if a piston was going to fail, it would be number 4 because it would be running a little warmer because it was running a little leaner. I think a high pressure fuel pump can alleviate some of that problem, but I don't remember. I'd have to peruse LegacyCentral again to see.

alia176 · #10 08-08-2010, 06:29 AM

what, no pics?

Crazy_pilot · #11 08-17-2010, 08:19 PM

Fine. Didn't take too many, it's been busy at work. The motor is 80% back together now. Beautiful rebuilt heads, all cleaned, new seals throughout... Just have to put one valve cover back on, drop it into the car, and install the intake.

Schralper · #12 08-18-2010, 04:19 PM

check out the weird looking wear pattern on my cylinder wall.
plug looks fine, no extra blowby either.

Crazy_pilot · #13 08-18-2010, 04:35 PM

Huh. That is odd. Nothing like that on mine, although I do have a bit of blow by on #5 and 6.

SVXRide · #14 08-18-2010, 04:39 PM

Quote:

Originally Posted by Schralper

check out the weird looking wear pattern on my cylinder wall.
plug looks fine, no extra blowby either.

looks like a pattern that the expander for the oil control rings would leave

-Bill

Cam · #15 08-18-2010, 06:07 PM

Quote:

Originally Posted by SVXRide

looks like a pattern that the expander for the oil control rings would leave

-Bill

That is precisely what I was going to say. It would appear that your number 1 and 2 rings are shot. Not on piston 1 and 2, but the top two rings on the piston inside that particular cylinder (my best guess anyways)

EDIT: is that oil that wipes away or physical marks that are scored into the cylinder?