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02-16-2009, 12:10 PM | #1 |
BENT VALVES in the head: tell me how that happens....
just like topic says. please tell me how valves in the head wind up getting bent????
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02-16-2009, 12:16 PM | #2 | |
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over revving.. stretching of the timing chain... vvti solenoid going bad and allowing too much timing advance..
or in my case.. snapping a connecting rod.
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02-16-2009, 12:36 PM | #3 |
got an 08 tc which was in before and had motor/head replaced under warranty for a ticking noise in the valvetrain. customer is back 3 months and 15,000 miles later and now ALL of the valves in the head are bent?
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02-16-2009, 01:09 PM | #4 | ||
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wait.. you're coming to YARISWORLD for tech support?
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02-16-2009, 02:04 PM | #5 |
Drives: '08 LB MT Bayou Join Date: Oct 2008
Location: Colorado
Posts: 1,671
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02-16-2009, 04:39 PM | #6 |
Don't drive it, RALLY it!
Drives: 1999 echo PRC rally car Join Date: Oct 2008
Location: Joyner, Brisbane
Posts: 321
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Does the timing chain still have tension?
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02-16-2009, 04:45 PM | #7 | |
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iirc the newer chain tensioners are oil pressure activated and ratcheting... so they'd take up any slack.. so yeah, you may want to check that the teeth on the tensioner are not worn off.. but i still sniff a mis-shift.
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02-16-2009, 04:50 PM | #8 | |
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not as much a problem as a slight source of amusement to me.. because most of the 'knowledge' on this forum orbits around what offset wheel you can run without rubbing and what weight of oil you can/cannot run...
so a question about bent valves being asked here where the OLDEST yaris on the forum (US, anyway) is approaching 3yrs old.
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02-16-2009, 06:52 PM | #9 |
probably because any talk of STREET RACING or ripping around the twisties with a new part installed is off limits....
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02-16-2009, 12:59 PM | #10 |
So what's the customer's story?
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02-16-2009, 01:12 PM | #11 |
and i quote " i drive 200 miles a day and never go above 70mph on the highway" and "all i did was get gas and car statred to lose power afterward"
car has intake and header( which were removed before he brought in) as well as secondary cat delete and megan exhaust..... |
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02-16-2009, 01:16 PM | #12 | ||
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warranty DENIED edit: have the tech pull off the crankshaft pulley and look for scoring on the roll pin.. you'll find it's most likely bent or almost broken.
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02-16-2009, 01:51 PM | #13 |
l33t3st Asshole
Drives: MY07 Yaris Liftback Join Date: Nov 2006
Location: Epcot
Posts: 588
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Assuming the install was done correctly Tamago is probably right.
although if the install wasn't done right it could be numerous things. |
02-17-2009, 01:45 AM | #14 |
Super Newbie
Drives: 2007 Yaris Liftback White Join Date: Jul 2007
Location: 626, Southern California
Posts: 180
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Valves were probably adjusted too tight if they had to do any kind of valve adjustment. Tight valves would lift too much causing contact with the piston and bending the valves.
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02-17-2009, 09:31 AM | #15 | ||
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tight valves.. lifting too much... yet somehow coming in contact with the pistons?? the valve springs lift the valves, the cams push them down.. blazinblue did your tech check the crankshaft pulley yet?
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02-17-2009, 12:49 PM | #16 | |
Super Newbie
Drives: 2007 Yaris Liftback White Join Date: Jul 2007
Location: 626, Southern California
Posts: 180
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Mis-shift would also be another possibility but he never mentioned if it was auto or manual. |
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02-17-2009, 07:26 AM | #17 |
Drives: 2008 Yaris Liftback (Sprocket) Join Date: Oct 2008
Location: San Antonio, Texas!
Posts: 2,799
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Does the Yaris have a rev limiter like my old Passat? I don't drive mine as wildly as I did my old VR6, plus it is an auto, so I don't know...
Cheers! M2 |
02-17-2009, 08:47 AM | #18 |
Joey
Drives: '14 Scion xD 5-speed Join Date: Oct 2008
Location: El Monte, Ca
Posts: 3,529
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Yes, it's set at 6K RPM. Valve damage would occur if driven for too long like that because of strain and overheating.
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Formerly owned Met-Met. '07 Yaris LB 5-speed. A forum post should be like a skirt: Long enough to cover the subject but short enough to keep things interesting. "I don't have an anger problem. I have an idiot problem." -Hank Hill |
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