FUBAR...opinions wanted.
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FUBAR...opinions wanted.
I posted this on preludeonline, thought I'd post this here also to get some more input...
I finally got around to tearing my motor down this afternoon. For those that don't know I've got an '01 Prelude SH with an fmax setup, minus the mf2, with 720's controlled by and AEM computer, and a built bottom end. Well to make a long story short I lost compression in #4 while on the dyno and suspected that it was due to excessive piston slap after pulling the head and seeing the scarring on my previously pristine GE sleeves. I waited a while to finish tearing it down both due to being pretty pissed and the fact that I'm still recovering financially from a period of unemployment last year (f*&$ing Lucent ) Just wanted to get your opinions, here are the pics:
The block was bored with only one piston (#1...go figure. )...not my choice, I didn't know until I got home and found 3 pistons still in their original packaging from JE. They must have done a hell of a job balancing too with the plastic still on everything...but I digress, I was pissed enough at how long they took I was in no mood to take the stuff back. Surprisingly enough the bearings look pretty good despite the amount of "glitter" in the pan...doesn't look like any damage was done aside from the obvious. Now that I have confirmation I'll be overboring (haven't decided between 88 or 89mm) and replacing the JE's with Wiseco's. Hopefully with the new pistons, some new bearings and some other odds and ends I'll be back in business soon.
--Ian
I finally got around to tearing my motor down this afternoon. For those that don't know I've got an '01 Prelude SH with an fmax setup, minus the mf2, with 720's controlled by and AEM computer, and a built bottom end. Well to make a long story short I lost compression in #4 while on the dyno and suspected that it was due to excessive piston slap after pulling the head and seeing the scarring on my previously pristine GE sleeves. I waited a while to finish tearing it down both due to being pretty pissed and the fact that I'm still recovering financially from a period of unemployment last year (f*&$ing Lucent ) Just wanted to get your opinions, here are the pics:
The block was bored with only one piston (#1...go figure. )...not my choice, I didn't know until I got home and found 3 pistons still in their original packaging from JE. They must have done a hell of a job balancing too with the plastic still on everything...but I digress, I was pissed enough at how long they took I was in no mood to take the stuff back. Surprisingly enough the bearings look pretty good despite the amount of "glitter" in the pan...doesn't look like any damage was done aside from the obvious. Now that I have confirmation I'll be overboring (haven't decided between 88 or 89mm) and replacing the JE's with Wiseco's. Hopefully with the new pistons, some new bearings and some other odds and ends I'll be back in business soon.
--Ian
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Re: FUBAR...opinions wanted. (proclassracer)
Uhh...it was on a wideband...actually 2 of them, the dyno's and my techedge setup. Never went leaner than 12.7:1
--Ian
--Ian
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Re: FUBAR...opinions wanted. (clendaniel)
Definately Piston to Wall clearance, things heated up, and your pistons started rubbing, i'd go to your machine shop and have a little talk. general piston to wall clearances on high silicone pistons are .035 -.45 somewhere in there.
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Re: FUBAR...opinions wanted. (lazerus)
Definately Piston to Wall clearance, things heated up, and your pistons started rubbing, i'd go to your machine shop and have a little talk. general piston to wall clearances on high silicone pistons are .035 -.45 somewhere in there.
--Ian
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Re: FUBAR...opinions wanted. (clendaniel)
Seized... That sucks man, your machine shop did you in on that one. i'd go to someone else for your problems.
it's quite possible they only bored one cylinder! You may want to get a nice set of calipers and measure an unscored part of all of your cylinder to check the clearances.
(probably at the very bottom is your best bet)
it's quite possible they only bored one cylinder! You may want to get a nice set of calipers and measure an unscored part of all of your cylinder to check the clearances.
(probably at the very bottom is your best bet)
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Re: FUBAR...opinions wanted. (lazerus)
Seized... That sucks man, your machine shop did you in on that one. i'd go to someone else for your problems.
it's quite possible they only bored one cylinder! You may want to get a nice set of calipers and measure an unscored part of all of your cylinder to check the clearances.
(probably at the very bottom is your best bet)
(probably at the very bottom is your best bet)
--Ian
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Re: FUBAR...opinions wanted. (clendaniel)
i trust my machinist. He gave me a (personal) garuntee. if they mess up, they'll pay to fix it.
they do DAMN good work here. being the owners friend does have it's benefits
they do DAMN good work here. being the owners friend does have it's benefits
#13
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Re: FUBAR...opinions wanted. (lazerus)
Definitely black death...new pistons, rings bore and hone time. Make sure the shop knows the proper piston to wall to bore with. This problem could very well have be caused by improper tuning rather than improper piston to wall.
BTW, JE pistons come balanced from the factory within a gram or two which is close enough. They should all be the exact same diameter and probably were but your shop should have at least checked them. When you balance the straight 4 cyl, you only need to do the crank. That's what most shops do.
IMO, if you rebuild with the same tune-up, the same thing will happen again.
You may want to consider skirt coating on the pistons.
BTW, JE pistons come balanced from the factory within a gram or two which is close enough. They should all be the exact same diameter and probably were but your shop should have at least checked them. When you balance the straight 4 cyl, you only need to do the crank. That's what most shops do.
IMO, if you rebuild with the same tune-up, the same thing will happen again.
You may want to consider skirt coating on the pistons.
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Re: FUBAR...opinions wanted. (earl)
Definitely black death...new pistons, rings bore and hone time. Make sure the shop knows the proper piston to wall to bore with. This problem could very well have be caused by improper tuning rather than improper piston to wall.
BTW, JE pistons come balanced from the factory within a gram or two which is close enough. They should all be the exact same diameter and probably were but your shop should have at least checked them. When you balance the straight 4 cyl, you only need to do the crank. That's what most shops do.
IMO, if you rebuild with the same tune-up, the same thing will happen again.
You may want to consider skirt coating on the pistons.
IMO, if you rebuild with the same tune-up, the same thing will happen again.
You may want to consider skirt coating on the pistons.
--Ian
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Re: FUBAR...opinions wanted. (clendaniel)
Looks like the motor got hot which probably was a lean situation. Running a 12.7-1 is pretty lean on a turbo car. I think he should have had it more around 12-1 12.2-1 . Id tell him to shoot for those numbers next time because something went pretty wrong. Also you might want to get those injectors flowed to make sure they really are 720cc.
Did you ever check the water level? maybe it ran dry as well? I know plenty of machine shops that only use one piston to bore if the piston is of a JE quality. They are into good enough spec to not have your motor look like that. Its either your tuner or a fuel issue which is kinda the tuners issue as well.
[Modified by ninesecrx, 6:45 AM 11/17/2002]
Did you ever check the water level? maybe it ran dry as well? I know plenty of machine shops that only use one piston to bore if the piston is of a JE quality. They are into good enough spec to not have your motor look like that. Its either your tuner or a fuel issue which is kinda the tuners issue as well.
[Modified by ninesecrx, 6:45 AM 11/17/2002]
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Re: FUBAR...opinions wanted. (ninesecrx)
Looks like the motor got hot which probably was a lean situation. Running a 12.7-1 is pretty lean on a turbo car. I think he should have had it more around 12-1 12.2-1 . Id tell him to shoot for those numbers next time because something went pretty wrong. Also you might want to get those injectors flowed to make sure they really are 720cc.
--Ian
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Re: FUBAR...opinions wanted. (ninesecrx)
Did you ever check the water level? maybe it ran dry as well? I know plenty of machine shops that only use one piston to bore if the piston is of a JE quality. They are into good enough spec to not have your motor look like that. Its either your tuner or a fuel issue which is kinda the tuners issue as well.
[Modified by ninesecrx, 6:45 AM 11/17/2002]
[Modified by ninesecrx, 6:45 AM 11/17/2002]
--Ian
#20
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Re: FUBAR...opinions wanted. (SEFI8LOxCivic)
We had a problem with a local machine shop not installing the sleeves correctly and this happened. It seems that it was easier to just bore the block bigger so the sleeve would go in easier rather than having to press it in. This resulted in the sleeves distorting and grabbing the piston just like this. Since you have golden eagle sleeves I don't think this is the problem. If your a/f ratio was good (12.7 a little lean) then it was probably the result of too much timing. How much timing were you running under boost?
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Re: FUBAR...opinions wanted. (lazerus)
i doubt he overheated it. and at low boost 12.7 is'nt too lean on forged pistons.
Black death can also happen little by little over time as well. It might not have been an isolated incedent. Since your rc's are brand new and they are 720's the fuel should be fine in the car since you only had 15 pounds of boost in it. What happened has a dircet coralation with overheating. Like Tony said as well, pull out a little timming in it. Do you know what you guys set it at? I think you should bring the af down like I said before. Theres no reason to have it that high...you can make the power on raising the boost, not leaning the car out.
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Re: FUBAR...opinions wanted. (ninesecrx)
And it is this exact reason that I will be checking my pistons and cylinders personally! That seriously sucks! Good luck with fixing the problem, let us know what you find out.
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Re: FUBAR...opinions wanted. (clendaniel)
Another thing to look at:
Even though you are running off a wide band, the adjustments that it makes do not happen as fast as the tune-up needs to change. This can give you momentary periods of the wrong settings. Most race cars run open loop and set the air fuel on the dyno to where they want it rather than trusting it to the constantly changing readings of an O2 sensor.
Even though you are running off a wide band, the adjustments that it makes do not happen as fast as the tune-up needs to change. This can give you momentary periods of the wrong settings. Most race cars run open loop and set the air fuel on the dyno to where they want it rather than trusting it to the constantly changing readings of an O2 sensor.
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Re: FUBAR...opinions wanted. (earl)
Another thing to look at:
Even though you are running off a wide band, the adjustments that it makes do not happen as fast as the tune-up needs to change. This can give you momentary periods of the wrong settings. Most race cars run open loop and set the air fuel on the dyno to where they want it rather than trusting it to the constantly changing readings of an O2 sensor.
Even though you are running off a wide band, the adjustments that it makes do not happen as fast as the tune-up needs to change. This can give you momentary periods of the wrong settings. Most race cars run open loop and set the air fuel on the dyno to where they want it rather than trusting it to the constantly changing readings of an O2 sensor.
--Ian