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| Forum name | Performance/Engine |
| Topic subject | The number one piston. |
| Topic URL | https://forums.2gnt.com/dcboard.php?az=show_topic&forum=i5&topic_id=135756 |
135756, The number one piston. Posted by 99eclipse420a, Jan-11-12 07:12 PM
I was having some misfire issues and so I did a compression test. I had 160psi across the board untile number one with a small 30psi. I removed the head expecting some sort of valve issue only to find the piston was sitting g uneven in the bore. It is lower on the transmission side below the deck and proper height on the timing side. Hopefully, you all will see this in the pictures.
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135757, RE: The number one piston. Posted by CODE4, Jan-11-12 07:31 PM
Drop the oil pan, and have a look underneath.
Time for a rebuild.
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135758, RE: The number one piston. Posted by 99eclipse420a, Jan-11-12 07:35 PM
That is my plan I will be taking pictures of all that I find. Luckily, I found a good engine at pullapart for temporary use.
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135760, RE: The number one piston. Posted by DarkOne, Jan-12-12 06:54 AM
Yeah, i'd say that's a damaged piston and an ovaled cylinder.
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135761, RE: The number one piston. Posted by 99eclipse420a, Jan-12-12 07:53 AM
Yes I agree with that. Also, the machinist honed the block at a 25 degree instead of 45. I believe he just treated it like a v8 instead of a inline 4.
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135762, RE: The number one piston. Posted by 420agreenvilleSC, Jan-12-12 07:56 AM
high comp time :)
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135763, RE: The number one piston. Posted by 99eclipse420a, Jan-12-12 08:03 AM
Mikey, I am not running anything to support that.
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135766, RE: The number one piston. Posted by 420agreenvilleSC, Jan-12-12 09:20 AM
FINE! :D FYI, i ovaled my cylinder(s) once too.. sucked, but thankfully i had a spare block that had standard bore measurements.
if you do infact do a rebuild, don't tell the machinist anything about the engine's history (or that you think a cylinder is oval), let him tell you what he finds first
worse case? if oval, you'll need to overbore and get new pistons :( best case? hone and reinstall w/ new rings :)
update this thread with your findings.. i'm curious
good luck!
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135773, RE: The number one piston. Posted by Slo2g, Jan-12-12 08:18 PM
Supporting mods for a high compression piston is an ECU! :P The stocker will run them!
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135777, RE: The number one piston. Posted by Dstach, Jan-13-12 12:05 AM
was the motor rebuild before? IIRC from the factort doesn't have std stamped on them. same with bearings. Could it be improperly put together?
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135780, RE: The number one piston. Posted by 99eclipse420a, Jan-13-12 06:36 AM
The engine is a rebuild with only 2000 miles on it.
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135824, RE: The number one piston. Posted by 99eclipse420a, Jan-18-12 07:19 PM
I removed it from the bore and lets see if the pictures give away what I see.
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135825, RE: The number one piston. Posted by CODE4, Jan-18-12 07:21 PM
Nice curve.
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135826, RE: The number one piston. Posted by 99eclipse420a, Jan-18-12 07:27 PM
Yes Dave it is. I was shocked.
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135827, RE: The number one piston. Posted by Slo2g, Jan-18-12 07:30 PM
Just what I was gonna say Dave :P sucks but now you know!
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135828, RE: The number one piston. Posted by 99eclipse420a, Jan-18-12 07:35 PM
The funny thing is it never knocked, just misfired at low rpm.
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135829, RE: The number one piston. Posted by JoshDSM, Jan-18-12 08:13 PM
Was the motor Na or boosted?
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135832, RE: The number one piston. Posted by 99eclipse420a, Jan-19-12 04:44 AM
It is NA with only bolt ons.
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