maxwagner

So I just pulled my head to find a bunch of small little chips all over piston #4
I'm not sure what I can do about this. Do I need to get new pistons or is there a different route I can take ? really do not have the time or $ to do the bottom end but if it must be done then I have no choice.
any insight helps.
thanks

Croustibat

You are quite screwed yes.

Bunch of small chips usually means lots of detonation, so you first need to find what caused them. If it only happened on 1 piston, it must be a faulty injector, injector driver or plug ... how is your plug ? Melted ?

The other possibility is your engine swallowed something, and it went into that cylinder. but this should also have damaged valves and turbo (or it could be a part from the turbo)

But yes, that is a case of changing at least 1 piston. You cant leave it as it, the chips will create more pits until it breaks and completely ruin the engine.

If you want to go cheap, just get a second hand one and put it in. It wont work as well as a rebuild, look at it like a temp fix.

Try to put some pics in there, it coud help too.

maxwagner

I just joined today and I'm still learning how to use this site ha.
I don't know how to post pics It would be so much easier if I could.
there doesn't look like there is any damage on the valves so I can imagine anything got in there right ?
once I figure out how to get a picture up of what the hell I'm talking about maybe we can get something figured out ha.

maxwagner

maxwagner

Got it !

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Croustibat

It is a bit hard to tell with that much crap on it

On top of the pic it looks like the piston is badly damaged too.

maxwagner

you should have seen it before I wiped it down
I can post more if you would like.
But as for cost effectiveness what can I do ?

joe3180

jw...why did you pull the head in the first place?

maxwagner

planned on doing metal headgasket , arp head studs just for a little extra security when drifting but then I ran into this ):

joe3180

You figure out what caused it yet? If not you prob want to figure that out first before trying to fix that.
My number 4 was also damaged. Luckily for me I was going to rebuild it when I found it out.


It always seems to be #4 piston problems though...lol. Good luck with your though.

Cheapest replace it used if nothing else is wrong but figure out the cause first so your not doing this again in a few months...or before it looks like mine. (mine was a whole other issue though)

maxwagner

Weird that they are both messed up in the exact same spot too. I think hopefully I caught this soon enough and I wont have to do to much extensive work to get this running again. I bet another thousand miles and mine would have turned out the same way.
when I bought the car the wiring was a nightmare so I'm going to take the wiring apart and see if I can get anything. ?
cheers for now

Croustibat

Cost effective wise, i'd just change that piston for a second hand one. But as said before, find what caused this, or it will happen again. My bet is on lean condition leading to det, or too advanced timing (causing det again). if the engine was modified and not mapped, or if the fueling system has the slightest problem, or if fuel octane is too low vs your timing, this happens.

dont bother installing a MHG, you need to get the engine block and head surfaced to get them to seal correctly. NOT installing it would be cost effective Just put a standard HG. HG blows when the car overheat, or when the surfaces are warped. A MHG will blow on the same conditions. A HG is supposed to be a fuse, you want it to blow, if it does not then something expensive will.

maxwagner

So like I said I was going to take apart the harness and what do you know...
The guy before me wired the injectors together injector 3 had its ground completely cut off and was soldered right to injector 1's ground.

Still trying to find why this would mess with the 4 piston being eaten up. :/

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maxwagner

This just keeps getting better. moved cylinder 3 up to the top to take a look after finding the injector wiring. It looks like someone took a cheese grater to the top of it.
yeah new pistons for sure.
thanks for all of your input guys

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heychris

That should be the picture right next to the word detonation in the automotive encyclopedia....

Last time I saw that bad was on a 2 stroke 125 I was roadracing.... That was after it locked the rear wheel at over 80mph, nearly causing my demise.

Like Croustibat said... You have MAJOR problems that need fixing or this will continue regardless of how many new engine internals you throw at it

Ch



Sent using XT912 M

joe3180

Ouch....how do the cylinder walls feel....might wanna start looking for a short block instead.

maxwagner

surprisingly the cylinder walls are still smooth, no damage at all really. You can still see cross hatching too.
But I'm meeting with a engine builder from around here and we're going to go over plans on how to go about this.
Thanks for your input

codyace

That's a good case of detonation, just make sure your boost levels are in check, your fuel is there and your tune is on. For it not to know a ringland out with that much detonation is amazing to say the least.

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Croustibat

If injector earth are soldered together, you got your problem.

Under a threshold, usually half load, the injectors fire sequentially; then it switch to batch mode, 2 jets per combustion cycle.

To command injectors, the ECU grounds them ...

If the previous owner grounded injectors together, it usually means the wiring is done for, and the ECU has had it too. I'd have the injectors cleaned and tested, to make sure ...

jamg

question, how would you know that one cylinder is damaged like that?

will the motor run like crap?

second, will the wideband read bad AFR's if one injector is bad?

how can you tell one injector is bad?

maxwagner

The motor ran just fine before it was pulled. I drove it daily with zero problems for about 10 months. But i was going to start tracking it so i took it apart to check everything and this showed up.
And i got brand new 550cc injectors anyway.
As for the ecu im going power fc when its all finished so , ehh this is just a minor hick up in the build.

fliprayzin240sx

If it was good before you took the head off (had good compression and not rod knocking), run it. Those are detonation pits, and a tell tale sign that you'd probably need a rebuild sooner or later. Cheap option is to go look for another good bottom end and swap everything over.

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sleepyS14se

is it a sr or a ka? i cant tell

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