What causes this to happen ?
bearings didn't let go. The car was actually driving fine and wasn't being torn down for any significant issue. The engine sounded like a lifter was on it's way out and as a precaution the heads came off to check it out... lifters were fine, but an exhaust gasket (ball gasket) was found to be loose and the sound we were hearing was likely from that. There were no audible sounds from the drivers side where this cylinder is.
This is the chamber of the cylinder that went, the other cylinders don't show any pitting of any kind. Number 5, directly in front of this cylinder, shows like it made light contact with the head as well in the same area as 7 (same coloring). All other cylinders look perfectly normal.
This is the chamber of the cylinder that went, the other cylinders don't show any pitting of any kind. Number 5, directly in front of this cylinder, shows like it made light contact with the head as well in the same area as 7 (same coloring). All other cylinders look perfectly normal.
It rattles like a diesel truck to the point of being anoying untill it gets up to temp .
Its an 404ci lq9 using a stock mls 6L gaskets and had 225-227psi/warm , afr 225 heads with 62cc chambers , comp cams 238/242-610/615-113+3 running 26 degrees with 93 octain and tr55 ir plugs .
Its an 404ci lq9 using a stock mls 6L gaskets and had 225-227psi/warm , afr 225 heads with 62cc chambers , comp cams 238/242-610/615-113+3 running 26 degrees with 93 octain and tr55 ir plugs .
Wow, yeah maybe you are on the right track with the excessive bore theory...mic the pistons. That combo definitely has a little squeeze though. If you measured a 4.035" bore, thats a 408. If you are right and have 404 pistons in there, somebody's got some explaining to do.
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From: Winter Springs
I measured it twice and it was 4.035. I havnt measured a piston yet but i will .
All i know is as a machinist i can see .025-.030 between the piston and the wall when the piston is cocked off to one side in the hole .
I will take more pics tomorrow and post them up .
All i know is as a machinist i can see .025-.030 between the piston and the wall when the piston is cocked off to one side in the hole .
I will take more pics tomorrow and post them up .
wonder if the rings did that?, pull that piston out and checked if the top ring shattered?when i used to build them old toyota engines from the 80's ive had a few of them do that..what happens is the top ring fails and shatters into little square shaped pieces..they get up in the cylinder and make contact with piston and head before gettin blown out the exhaust..this has happend to me after i had the engine bored..
Last edited by allan808; Nov 17, 2009 at 04:08 AM.
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From: BFE
Oil contamination will cause carbon buildup which in turn can create hotspots and pre-ignition. Maybe that's what seems to have happened in this case. Your motor was running rich as well.
The cause could be too much blow-by due to improper piston to wall clearances, I would get the block inspected.
The cause could be too much blow-by due to improper piston to wall clearances, I would get the block inspected.
Last edited by PREDATOR-Z; Nov 17, 2009 at 10:15 AM.
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The damaged area closer to the bottom of the relief definitely looks melted (detonation). The pistons don't "look" to have extreme clearance. Wall clearance is measured so far down from the pin, not from up top above the rings.
Is the ring broken out of the land anywhere?
Is the ring broken out of the land anywhere?
Check your fuel injectors, if that cyl's injector wasn't working at all (possible) you could have gone way lean in that one hole and that in turn did cause that syl to run lean/meltdown.
I know more then one person that's happened to. Having injectors flowed/cleaned once a year is now a routine I am going to be religious about.
I know more then one person that's happened to. Having injectors flowed/cleaned once a year is now a routine I am going to be religious about.
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From: Winter Springs
Check your fuel injectors, if that cyl's injector wasn't working at all (possible) you could have gone way lean in that one hole and that in turn did cause that syl to run lean/meltdown.
I know more then one person that's happened to. Having injectors flowed/cleaned once a year is now a routine I am going to be religious about.
I know more then one person that's happened to. Having injectors flowed/cleaned once a year is now a routine I am going to be religious about.
I guess what I'm getting at is that the piston didn't just randomly come apart. Something happened (combustion-wise) to make the land want to lift i.e. heat, ping, overly rich mixture burning in the ring land, etc... You may never know why for sure.
I'm curious to see what tour wall clearance comes out to as well although nothing looks too whack in the pics.
It really sux we can't do individual cylinder correction with the PCM!
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More than likely that cylinder ran lean I have seen this many times on fords. People break a piston have the short block rebuilt then down the road same thing happens. When they lean out they ping and break apart. Seen it many times in many engines. With old time carbs it rarely happens. But with injection it can happen. Have that injector tested for flow just for your own satisfction. Sorry DUDE
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From: Winter Springs
Time for a bigger cam .
Detonation was the problem ppl and im pretty sure it had to do with the extra material getting taken off the heads the last time they were cleaned up . I have no idea what the cc is of the head after the work was done and i should have check it before continuing with the same motor combination .
This combination worked great for a year and a half but after the head work
it looks like it needed higher octain fuel or a different cam that would bleed off compression better .
The builder is going to rework the short block and get me up and running again , the heads are at the shop now getting cc'ed and im going to most likely get a bigger duration cam .
Live and Learn i guess :/
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From: Winter Springs
A 10mp camera in s/macro mode at 3 inches can make things look really good or really bad :/
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From: Winter Springs
After taking the motor apart there IS melting around the vertical edge of the pistons 5 and 7 .
After finding out all the proper values my friend wrote me back and said .
" I keep getting 13.1:1 for compression ratio and I’ve tried like 3 different sites online.
Also, that makes the dynamic compression ratio 11.6… WAY too high for pump gas. "
lol
After finding out all the proper values my friend wrote me back and said .
" I keep getting 13.1:1 for compression ratio and I’ve tried like 3 different sites online.
Also, that makes the dynamic compression ratio 11.6… WAY too high for pump gas. "
lol
After taking the motor apart there IS melting around the vertical edge of the pistons 5 and 7 .
After finding out all the proper values my friend wrote me back and said .
" I keep getting 13.1:1 for compression ratio and I’ve tried like 3 different sites online.
Also, that makes the dynamic compression ratio 11.6… WAY too high for pump gas. "
lol
After finding out all the proper values my friend wrote me back and said .
" I keep getting 13.1:1 for compression ratio and I’ve tried like 3 different sites online.
Also, that makes the dynamic compression ratio 11.6… WAY too high for pump gas. "
lol
WHOA!! Your lucky the rest looked that good......