Zander916

So the car has been running a little funny lately. I couldn't quite put my finger on what but it just didn't seem quite right.

Tonight I drove my 35+ miles home from work and all was well. Then, I took my exit and as I was coming to a stop it died. It would not restart. I sat there for a bit trying.
I reset the ECU with my tuner and tried again. It didn't want to but I gave it some gas and it finally restarted so I could finish my couple more miles home. I had to keep giving it some gas to keep it going. Driving along it kinda sounds like a Subaru.
I get home where it doesn't matter if it dies but it doesn't die. This brings me to what it's doing.

It idles very very rough. It's very difficult to start and won't unless I give it gas. The other unusual thing is that while it's idling it's only at 2-3 inHg. It's boosting at idle.

No CEL as of yet.

Any ides?
Stuck waste gate?

mods - forge bpv : been on for about a month
Catted Downpipe / zzp : been on over a year
K&N intake : been on about two months
BSR PPC tune : had it for almost 70K miles now

D1sclaimer

I don't think its boosting at idle. If it sounds like a subaru, you are missing a cylinder. That would also cause it to not pull a lot of vacuum. Pull your plugs and see if any are wet and check how they look.

Zander916

K... I pulled the plugs. First two (passenger side) were a bit worn off.
But the end plug on the drivers side is covered with oil. Peering into the head that cylinder appears to have a puddle of oil sitting in it.

Soooooo.... *sigh* is it looking like I'm another victim of the cracked piston ring?

EDIT: Doing some research.... sure sounds like ringlands to me. Damn....
If you all feel like it's the ringlands are toasted. What are your thoughts on forged pistons? Any drawbacks? Also, where can they be bought from? ZZP appears to be out of stock.

SSlobalt

Ugh. Sorry to hear about that, dude.

Stamina

Well the main problem you face with forged pistons is the mileage on the car. I saw that you had 70K+ miles on the car based on how long you've been running the BSR tune.

Over time, the pistons wear away the normally traveled length of the cylinder wall, but not the top/bottom. This creates a "necking" at the top and bottom that can snap the rings of a new set of pistons. If the car had fewer miles, this wouldn't be an issue at all.

Once you open up the engine, you can have a builder or somebody knowledgeable measure the cylinders for diameter and necking, and check the walls for scoring. You'll need to hone them at a minimum.

If the walls are too far out of spec, you'll need to bore the sleeves to the next size and buy the cooresponding size pistons, or replace the sleeves in order to start fresh.

Zander916

My buddy who builds Mustangs and Subarus is gonna pop by next week and do a compression test. If its confirmed then its on to some forged pistons and a new clutch. There is a cheat way to replace the pistons but we'll just do it right and pop in a new clutch too.
All of course after we confirm what we think it is.
It sucks a LOT and it'll be a lot of money but it'll be better than before. Plus my buddy is super cool so he will hook me up proper.

Zander916

Yeah, I think once he is in there he will check the walls out and hone them at a minimum. Sorry if this double posts... on my phone currently.

Stamina

Yeah, instead of combining posts, the forum has been doing individual posts for a while now. I guess somebody flipped the switch on the auto-post-combine option.

seeyaass

Ouch, you still have your warantee? Why not bring it to the dealer?

Zander916

I could dp the warranty thing..... well... try. But I'm looking at it like this. If it broke then I want to replace it with something better. My friend will set me up very nicely on the labor end and I fully trust him, not the dealership.
I don't mind sending him some work and some cash to do a great job. He has kids and a wife to take care of too so why not I guess.

SSlobalt

You need to teach your honorable ways to many others on this site.

seeyaass

Well if u have the money then do it up I guess!.. what caused the ringlad crack? This actually happened to a friend of mine with an srt4, car use to smoke like a bitch cylnder 4 sparkplug wold be caked in oil within a day.. he went the same route you are doin

Zander916

Well, I think just time, heat, and pressure. I noticed the last few days it would idle at 18 inHg instead of 20. (poor vacuum I assume) although it ran fine otherwise. I killed it twice taking off which I thought was strange. I never do that.
Then I got on it last night and that must've been the straw that broke the camels back as they say. It ran fine for about 8 more miles or so. I took the exit and that was it for the car. It gave up the ghost then.

So in short, I don't think it was really one event that did it. But it was one event that finally pushed it over the edge.

seeyaass

Ouch man sorry to hear that, wish the best of luck.

cubaniche

iTrader: (1)

Your kinda in the same situation as I was at the beginning of last year except I already had the wisecos sitting in my closet and I only had bout 16k on the odo. A timely thing because a few weeks later I popped a ringland. I assume it was a combo of my aggressive driving habits while being tuned that did my engine in. I applaude your wanting to replace them with something better. You won't be dissapointed. I also had two buddies that did the work while I helped a bit lol
Good luck man!

Zander916

Thanks man! I'm going to replace with better parts if they break whenever possible. I don't want to have to do this all over again later down the road. Did you notice side effects from having the forged in there? (positive or negative) Where your piston tops covered with carbon/soot?

Does anyone know are people escaping without cylinder wall damage?

SSlobalt

All the pics I've seen are of guys with cylinder wall damage. It's just not likely that you'll get away without sleeve work.

Stamina

With forged pistons, you'll have a bit of piston slap at first on cold starts. Through advancements in materials and production, the tolerances can be tighter than the older forged pistons, but they'll still make a bit more noise at start up. It's normal though.

It's a trade-off. Forged pistons need to be up to temp before getting on it, but they're stronger.

When my #1 bit it, my sleeve was fine. Ironically my #3 showed a bit of scoring though. I've been toying with starting with a fresh set of forged pistons myself, but I think my mileage is way too high at this point to do that cheaply. I'd probably be looking at having to bore at a minimum, and then you're looking at possibly weakening the sleeves, so might as well resleeve... and that costs more money...

Zander916

Well, compression test done. It was VERY ugly.

128, 135, 148, 30 <---- yes that's right... 30

So my buddy is going to trailer it back to his place and pull the head to see what we're dealing with. He's concerned about bore damage as am I. There's just nothing I can do though until we figure that out except maybe weigh out my best and worst case scenarios and try to be prepared.

Assuming things are ok enough to save it.
I'm kind of ruling out that particular tunes are causing this. I mean, obvious some are worse than others and this and that but it seems to be happening across the board. We found a case of GMS1 and I think even a totally stock one has had this happen.
If it works out that I can I was thinking of trying to pull the trigger on an intercooler while I'm at it. (Just noticed that Treadstone has a kit for $300. It's looking awfully tempting since I'm blowing money anyway!) I was just curious if you guys thought a bit cooler air would help or what steps can be done. I'm thinking the air coming in being too hot could be a problem perhaps. (?) Or maybe just forged pistons is enough that I won't have to worry about this again.

EDIT: Just did a bit of my own research. It looks like cooler air will help against detonation so I'm hoping the damage starts turning out in my favor and I'll likely pick up that Treadstone kit.

cubaniche

iTrader: (1)

Man sorry to hear about that last update. Thats damn low in that last cyl LOL I had low compression on only one cylinder. When I took my engine apart there was no sidewall scoring. In fact, all four still had very visible crosshatching. What saved me was that the rings themseves, on the one that failed, were intact. I guess I had a microfracture start on the middle ringland until it completely broke off but did not separate from the piston itself. Only when I took that piston out and removed the rings did that little piece just fall off LOL
I was very lucky that it didnt come apart in the cylinder.
Keep us posted man and good luck!

Zander916

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Well this is what was found in Cylinder 4. Another guy we both know who owns a machine shop is gonna stop out Monday to inspect it and give us his opinion.

Wangspeed

iTrader: (2)

Needs oversized pistons or a replacement sleeve.

Zander916

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Oops

Zander916

PISTON #2 - There's the crack he's point at and then another one further to the right. That whole piece between was just sort of floating between the rings.


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gtsr100

yea im taking my pistons out this week so should be intresting i got 56k on it new head and every thing as well