SR20 Pistons Fried Input Needed! Pics Inside

[Rob238449]

Hi All,

I just bought my first SR Swap. I leaned yet another hard lesson by taking another mans word :rolleyes: . Anyway i did a compression check after i got home on this impulse buy and realized i had 0 compression in 1 cylinder. Hoped for a valve and come to see this.....

http://i39.photobucket.com/albums/e166/Pgtampa/Mobile%20Uploads/IMG_20131130_192806_260.jpg (http://s39.photobucket.com/user/Pgtampa/media/Mobile%20Uploads/IMG_20131130_192806_260.jpg.html)

http://i39.photobucket.com/albums/e166/Pgtampa/Mobile%20Uploads/IMG_20131130_192818_238-1.jpg (http://s39.photobucket.com/user/Pgtampa/media/Mobile%20Uploads/IMG_20131130_192818_238-1.jpg.html)

Do you guys think this is salvageable and if you were on a budget what would be the best way to go about this, and what exactly would cause this? Detonation, Pre Ignition?

I have a new ring set and oem pistons in the garage, but I'm guessing this is passed a rehone and new piston?

Thanks ahead of time!

[brndck]

Better idea, take it back to who ever you bought it from and bring a fucking baseball bat.

[Dboyizmlg]

That's dirty!
That dude screwed you.... I would take his ^^ advice.

[Rob238449]

I want to, trust me but I have other things to worry about like my baby on the way. It's a project not necessary and would just like to see it running! I have taken a step back and realized small claims court will get no where and he is not worth my career.

I just can't believe that the parents supported him because the father (Mechanic) and mother were there as well. After taking it apart it was obvious someone was just in that motor. Oh well......Normally I'm very cautious but i didn't listen to instincts, My mom would have whooped my a** but karma is a B*tch...

Anyway, is there a way to salvage this block with the way the cylinder looks?

Most of the damage is on the top of the cylinder and there seems to be little to no scoring.. I haven't cleaned the cylinder, I just snapped pics a son as i saw it but upon inspection It is a white carbon that comes off after TLC. If the rod is still good will I be able to rehone and install new piston and rings, Or am I completely wrong here.

[Dboyizmlg]

You will need a bore, and hone!
Possibly some sleeves in the cylinders if needed.

I honestly think you're block might be ok.
Just take it to a reputable engine builder and go from there.
GL!

Btw... KARMA is a Bit$%z

[oni jake]

Break it down completely and bring it to a machine shop. It looks salvagable. Maybe 200 in machine work, then add in replacement parts.

[Rob238449]

Thanks allot guys, I don't know to much when it comes to machining. WillIi still be able to utilize the oem pistons size and rings after the machine work? 200 in machine work doesn't seem to bad!

[Dboyizmlg]

No, you will not be able to use the same size piston.
You need a bigger bore size.

Reputable machinist will let you know the details.

[codyace]

It will need to be rebuilt. New bore, new pistons, new bearings, new rings, etc etc etc.

[Rob238449]

Thanks for the input guys, I'll be pulling the motor this week to check it out internally. So changes are the bearings are shot to? SHOULD this have caused damage to the crank as well? I might as well buy a short block If it is that bad!

[brndck]

Based on the condition of that bore I would recommend a full tear down. Replace crank bearings, inspect crank journals (if you have the time and $, now would be a perfect time to wpc treat some shit. That treatment is amazing for engine internals).

[codyace]

Thanks for the input guys, I'll be pulling the motor this week to check it out internally. So changes are the bearings are shot to? SHOULD this have caused damage to the crank as well? I might as well buy a short block If it is that bad!

I'd say without even tearing that engine down, you may as well consider the fact that you'll be spending darn near a grand in parts alone, labor aside....

500ish for pistons, 100ish for oem rod and main bearings, machine time, new gaskets, new headgasket, etc etc.

[Sforteen]

id take it apart, clean up the bores with scotchbrite, try to get that aluminum from the pistons off the cylinder wall... throw a dingle hone down its throat and wala.. get some new cast pistons and rings and be done..

[brndck]

id take it apart, clean up the bores with scotchbrite, try to get that aluminum from the pistons off the cylinder wall... throw a dingle hone down its throat and wala.. get some new cast pistons and rings and be done..

I hope no one ever listens to you for advice.

[codyace]

id take it apart, clean up the bores with scotchbrite, try to get that aluminum from the pistons off the cylinder wall... throw a dingle hone down its throat and wala.. get some new cast pistons and rings and be done..

It looks like the liner has a chip in it, how is a bottlebrush going to fix that?


Don't get me wrong I've sorted PLENTY of 2 strokes that overheated and smeared the walls, and used a bottle brush to clean them up new...so I know the magic of the ole flex hone....but it's not gonna save divits, especially up top wear the rings ride.

[Kingtal0n]

sigh used parts. I am sorry for your troubles.

You might want to think about getting a used longblock and keeping that engine for spare parts.

[Sforteen]

I hope no one ever listens to you for advice.

Why? Dudes on a budget already has most of the parts.. just because you don't have the know how to do it doesn't mean it won't work.. I've probably built twice as many engines than half the people on this forum.. There is no reason to have a machine shop do it if you can get that aluminum off the cylinder wall safely.. clean up the bore with a hone after you get the aluminum off and it will be fine.. I've done it. Successfully.

You should replace the rod bearings as well.. chances are the upper halfs took a beating from the detonation and lost there tension.

As for the "Chip" it looks to me that its just the aluminum that transfered to the wall.. cylinder walls don't generally chip... they crack.. and I don't see any coolant..

I don't post much on this forum.. take my advice for what you want.. it might be fucked.. I'm not in front of the engine to look first hand.. just saying the above method can work just fine..

[Rob238449]

Thanks guys, took the motor into the machinist and he used micreate acid on a Q Tip and it literally ate the the melted aluminum of the wall. What seemed like pitting to me was the aluminum build up.

It almost seemed like nothing happened afterwards, he is going to check for stress and cracks and inspect the cylinders as well he will let me know all that needs to be done after.

I will be ordering new bearings, rings, pistons at the very least though, who knows what else this guy neglected to tell me. Regardless I'm hoping for the best but I am prepped for the worst.......my girl has an expensive Christmas list and NOW so do I lol.

[codyace]

As for the "Chip" it looks to me that its just the aluminum that transfered to the wall.. cylinder walls don't generally chip... they crack.. and I don't see any coolant..

I don't post much on this forum.. take my advice for what you want.. it might be fucked.. I'm not in front of the engine to look first hand.. just saying the above method can work just fine..


I'll agree they don't normally chip, but I've seen plenty of 'hot' SR's break 'chunks' out of the liner like that, all on the top side of it all too. Don't ask my why, but it does happen.

With that said, a flex/bottle hone works, and is a cheapy way to try...but in the same regard now we're asking him to tear the engine down as it is....at that rate if he's not mechnically inclinded it's a loss.


I'm all for sloppymechanics, but in the same regard we need to consider the overall ability of the mechanic at hand. I've slapped shit together knowing full well it won't last, only to have it outlast 'built' engines too...gotta know the canvas before you learn to paint :D

(Off topic but I actually brush honed a set of Indy Tripel heads tonight for my buddies Sled...they were totally smeared up...cleaned em up perfectly! I love these things)

[ShadowMan]

I rebuilt my motor with all new bearings, pistons, rings, hg, bottom end all arp, new timing kit, water pump,valve seals and some other stuff. If you rebuild it yourself, you're easily looking at $1,500, if you go for all new basic stuff. Also figure in for all the tools you'll have to buy to complete the job properly,unless you have everything or friends that do. Plus all the little shit that manages to work it's way into your budget that you just have to have or might as well do since you're in there, like main seals, flywheel resurface, and so on and so forth.