legacycentral bbs

Well, I seem to have finally damaged my motor. What exactly broke/burst I don’t know yet. I was running about 8 lbs of boost and a 60 shot of nitrous when the engine hesitated in 4rth gear and smoke appeared out the back. Then I shut down and turned off of the track and slowly idled/drove back to the pits. Other than running rough, the engine ran ok with no bad noises or grinding.

I pulled into a spot under a streetlight in the pits and listened to the engine and all I could hear was the normal sounds except for the bad idle and “missing”. However, I know a true shot valve “miss” and this wasn’t sounding anything like it.

I shut the hood and drove to a true parking area and re-examined the engine in darker area so I could not see deep into the engine bay. At this point I realized that there was oil sprayed up everywhere on the rear of the passenger side of the bay. But at idle, there was NO oil dripping down onto the pavement. However, smoke is everywhere as the oil burns off on my exhaust. I idle the engine and rev it a few times and now see smoke blowing out of the rubber throttle body connection (where the intake is attached to the throttlebody.) when I let up on the throttle. I feel around the connector and find a bad tear on the bottom and figure out the smoke from the crankcase ventilation hoses.

So at this stage I am about 100% confident that the rough idle/running is due to the torn throttle body intake connector. Ie a vacuum leak.

As for the oil, I have no clue. There is oil puddled up on top of my passenger side head and I am smoking like a motherfukker as it drips onto my exhaust. Supposedly I am also smoking out my tailpipe a little, but as for that it really does not look like a blow valve or ring at this stage. Damaged maybe, but not shot.

I must have blow either the headgasket or valve cover gasket at high boost, and since I am only at high boost when I want, I am not leaking/spraying while normally driving.

Ah crap. More money into the quest of powah!

What did you do about the PCV system? Is it possible that your crankcase is pressurizing under boost?

More than possible. I did not consider that. How do the ej22t's accomadate this?

I don't understand the exact mechanics of it (witness this thread: http://bbs.legacycentral.org/viewtopic.php?t=16496), but basically it somehow allows for the partial vacuum at the compressor inlet to suck crankcase fumes in.

Maybe you need to plumb something into the intake upstream of the supercharger... I dunno.

Well, upon checking over the engine a little more thouroughly this morning, it appears I have lost a piston as I am only firing on three cylinders. Whichever is the closest to the driver is the one that is not firing. I pulled the plug and it is black with oil and gas.

I guess this might be why I am blowing so much oil, for if the piston has a small hole in it and is still working, ie trying to compress the air, then this air is getting into the block and forcing oil out. Does this sound right? This would explain that huge surge of oil that blew out durning the end of the 1/4 mile run when the supercharger was still boosting but suddenly a hole appeared!

I don't mind driving around on 3 cylinders, heck I did that for the first month when I first got the car, its all the smoke from the oil burning off the exhaust that is embarrassing! I come to a stop and the car starts to smoke like its on fire!


Well, time to start saving for another rebuild kit!

That's cylinder #4, and evolutionmovement thought he ate his #3 piston when he just sucked an exhaust valve...

Yeah, with all the oil I had I thought I lost #3 piston. I thought the thing might partially hydrolock for all the oil it seemed to be getting in the cylinder. I stuck a piece of hose with a coat hanger inside in the spark plug hole to explore the cylinder for a hole or something and pulled up bits of metal. I pictured gouged cylinder walls and a blasted ring land, but when II tore it down it was just a very melted exhaust valve. Vikash, Matt, Phil, and Scott saw it at the meet. It's quite the accomplishment on an N/A engine, if I do say so myself! Anyway, the entire nearly 250k mile engine looks brand new inside but for the one valve. Even the seat isn't damaged and the valve lost about 1/3 of its surface area. I thought it was strange that I would blow a piston like that especially as they seem to be a fairly robust design.

Point is, you may want to check that it's not a valve first. I still don't know why mine melted, but best guess is too much carbon build up reduced the exhaust's heat sinking ability and when I was holding it at red line around a long tight onramp the extra heat just became too much. Vikash also suggested an air pocket or blockage in the cooling passages, which is another possibility.

Hm, anyway, if you want to do it cheap and you did blow a valve, I can send you one (one that's not burnt). I don't know what they cost new and of course it's not the best idea to reuse old valves, but it should be OK for a beater.

Steve

I drove the car around a bunch today and while I havent had a chance to actually test compression, I must have some since the car runs better with the fuel injector running versus having it unplugged.

On the freeway, it still cruises at 70-80 if neccessary, just takes a while to get there.

Pulled the engine tonight. The top of piston #4 was missing. The rest of the valves and piston heads looked fine.

Ring land?

Steve

I just pulled the pistons out this morning. All "looked" fine except #4, which I was lucky didn't completely come apart in the cylinder. There was the little missing piece on the top, as you look at it while installed. When I pulled it out, all the rings were bust, and the aluminium was completely broken all the way around except at the two thickest points.

Your description sort of reminds me of a similar incident I had with my Trans Am. I cracked a piston while overboosting:



Anything similar to that?

Similar, but just barely. Mine just barely cracked off and then burned real good. I will get a picture soon.