OK, if you saw my other recent post, you know I had to take my head off my motor to get at the gasket that I put on upside down (I copper sprayed the gasket and covered up the "up" on the gasket...i'm a n00b... )

Well, I remove the head and this is what I find in cylinder no.2...



the scar is just deep enough that I can slightly catch my nail on it, then it gets lighter, to non-existent towards the top...

do I need to hone it? it's already bored .20 over...

thanx again...

 

If your finger nail catches on it you'll need a rehone. Most likely you'll need to go to a larger borea as well.

By the way, notice the edge of your piston. Is that grease/dirt or did you melt the side of it? I'm guessing dirt since the majority of pistons that 'melt' do so near the intake side of the piston. If it is pourous I would pop the pistons out and inspect them closely.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PrecisionH23a &raquo;</TD></TR><TR><TD CLASS="quote">If your finger nail catches on it you'll need a rehone. Most likely you'll need to go to a larger borea as well.

By the way, notice the edge of your piston. Is that grease/dirt or did you melt the side of it? I'm guessing dirt since the majority of pistons that 'melt' do so near the intake side of the piston. If it is pourous I would pop the pistons out and inspect them closely.</TD></TR></TABLE>

it's dirt...the pistons are fine, I haven't even broken this motor in yet! it ran for about 15 sec. before I shut it down the first time...

if I do need a bore, how would I go about doing that w/ the motor still in the car? or does it need to be broken down again? what would cause the rings to gouge the walls like that?

 

That kinda looks like the marks left by piston rings butting against each other.

Who gaped your rings?

 

To have the block bored you will need to pull the motor again. Who assembled the motor?

 

ouch. That happend in 15 seconds? no way.

 

that looks bad, maybe a ring was broken when the pistons were installed, or it might be a wrist pin that was installed the wrong way and came out after you started the engine. Some times the c-clips don't seat 100% and its hard to see, I almost installed one of my pistons with a c-clip that would not seat in the grove, it just looked wrong to me so I kept looking at it, hitting the wrist pin or the c-clip didn't help, I had to reinstall the wrist pin from the other side of the piston but it went in the groove and it looked right.

 

id say the rings caused that, as teh scrape looks fairly broad and i doubt a wrist pin would contact the cylinder wall like that.

 

Possibly the wrist pin?

Same thing happened to my freinds DSM motor.

 

looks like i'll be dropping the oil pan in the next few days to take out the piston and inspect it...

i think i'll just do some honing to it and see how it turns out...

if there is still some catching on it, what's the worse that could possibly happen??

 

i would say it is a wrist pin.post pics when you get it out.it will most
likly need t be bored.

 

i dont think it could be the pin, look how high the scrape goes up the cylinder wall, has to be ring related

 

will this effect blow-by and/or compression? I wonder how bad of an impact this will have on the motor if it's still mediocre once I hone it a little...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by originalsin &raquo;</TD></TR><TR><TD CLASS="quote">i dont think it could be the pin, look how high the scrape goes up the cylinder wall, has to be ring related</TD></TR></TABLE>

I concur, unless he's got some new fangled type of pistons and ultra long rods...

 

Definitely rings.

BTW, that outside part of the valve relief looks to have already broken off? Hmmm...

 

 

Holy crap dude, I feel bad for you. Its pretty damm fubared, an hone will probably cover it up and make it feel good. However the cylinder roundness is damaged. You really need a .10 over hone to fix it right.

What I would do is probably try to run the motor on those pistons and try to cut your losses. Try to break it in and see if you can get it within 15% of the other cylinders compression.

I bought my eclipse allmost 4 years ago now with a broken pistong ring in cylinder #2. The cylinder wall is scratched a little (but you can't feel it). Only has 127 psi compression on that cylinder. The damm thing runs great, go figure.

If it doesen't break in right and has too much blowby, tear it all apart and start from scratch.

Warning: I'm a farmboy, your milage may vary. Listen to me at your own risk.

 

i just built my first motor. not in the car n fired up yet but any tips on figuring out if you broke a piston ring while installing&gt;?

 

the piston should go in without much force

 

Think about how many times it went up and down in 15seconds.
15/60 = 25%
Let's say idle (when cold) = 1500 Revolutions/Minute

25% of 1500 = 375 Revolutions . . .

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by danl &raquo;</TD></TR><TR><TD CLASS="quote">Holy crap dude, I feel bad for you. Its pretty damm fubared, an hone will probably cover it up and make it feel good. However the cylinder roundness is damaged. You really need a .10 over hone to fix it right.

What I would do is probably try to run the motor on those pistons and try to cut your losses. Try to break it in and see if you can get it within 15% of the other cylinders compression.

I bought my eclipse allmost 4 years ago now with a broken pistong ring in cylinder #2. The cylinder wall is scratched a little (but you can't feel it). Only has 127 psi compression on that cylinder. The damm thing runs great, go figure.

If it doesen't break in right and has too much blowby, tear it all apart and start from scratch.

Warning: I'm a farmboy, your milage may vary. Listen to me at your own risk. </TD></TR></TABLE>

I say pull the motor apart, sell 3 of the pistons, and buy 4 new ones in a larger bore. Then make sure it is assembled right this time. . .

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by originalsin &raquo;</TD></TR><TR><TD CLASS="quote">i dont think it could be the pin, look how high the scrape goes up the cylinder wall, has to be ring related</TD></TR></TABLE> deffinitly ring related, maybe the end gap was not to spec?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Finest &raquo;</TD></TR><TR><TD CLASS="quote">Definitely rings.

BTW, that outside part of the valve relief looks to have already broken off? Hmmm... </TD></TR></TABLE>

the piston(s) are fine...those are JE 9.8:1 comp. .20 over pistons....they came that way from the factory...

as for the block...i'm just gonna hone it a little and call it a day... this is my daily driver, so I can't go another month or two rebuilding this motor...i'm just gonna run it like it is and see how it turns out and pray for the best..

soooo, is there anything I can do to minimize the effects of this?

 

Well, in order to hone it, you need to pull it apart. Just purchase a new set of rings and be very careful installing them..
Am I right in saying that you have to pull the pistons to hone it? I think so . .

 

yup you will have to pull the pistons, man i think i would pull the motor and remove the crank just to be safe.