burnt valve questions...
Thread Starter
*Bad Trader*
Joined: Nov 2001
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From: here and there
burnt valve questions... well...one nite i broke off the "L" shaped part of the plug( no ses light all the way home), next day i replaced plugs/wires, then i get ses light (flashing,P0305)multiple misfire in #5 cycl. so i check rockers,pushrods an springs, all fine as far as i can tell,only thing left is burnt valve (n20 motor, 150 wet)
1. what does a burnt vale look like
2. can i just get new valves or do i need to do seat work,
compression test shows just slightly lower than all others on that side of the engine. will anything eles cause a misfire other than what ive talked about, maybe injector.
ps somtimes the ses light comes on but dont flash, all stock motor ecept n20 please im out of ideas <img src="images/icons/mad.gif" border="0">
1. what does a burnt vale look like
2. can i just get new valves or do i need to do seat work,
compression test shows just slightly lower than all others on that side of the engine. will anything eles cause a misfire other than what ive talked about, maybe injector.
ps somtimes the ses light comes on but dont flash, all stock motor ecept n20 please im out of ideas <img src="images/icons/mad.gif" border="0">
Re: burnt valve questions... Oops :-/
Doesnt sound too good to me.
Try the choo choo test. With the car idling, remove the oil fill cap and put your hand over the hole. Feel a pulse?
If not, when that cylinder is at TDC, run a straight edge over the other closed valves and see if a valve on that cyl. is lower (can slip paper in, can slip a feeler guage in, etc.)
What happened during your driving right prior to this?
Hmm? Hmm? Hmm? ;-)
chris
fully recovered previous n2o addict
Doesnt sound too good to me.
Try the choo choo test. With the car idling, remove the oil fill cap and put your hand over the hole. Feel a pulse?
If not, when that cylinder is at TDC, run a straight edge over the other closed valves and see if a valve on that cyl. is lower (can slip paper in, can slip a feeler guage in, etc.)
What happened during your driving right prior to this?
Hmm? Hmm? Hmm? ;-)
chris
fully recovered previous n2o addict
Thread Starter
*Bad Trader*
Joined: Nov 2001
Posts: 1,459
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From: here and there
Re: burnt valve questions... i was just driving down the freeway and i got off to get gas an noticed a miss,dont know exactly when did ut, i sprayed about 45 min befor but no miss afterwards, expain you method again for chcking for bad valve im confused as allways
TECH Fanatic
Joined: Nov 2001
Posts: 1,027
Likes: 2
From: KS
Re: burnt valve questions... I don't know about the burnt valve thing. Could be. But the tip missing from the spark plug is common for a motor that is detonating. With NO2 that is an even bigger possibility. These motors have crappy hypereutectic pistons. These pistons don't absorb heat. So the heat is transfered to the rings. If the gap on the rings are not large enough the rings will butt and tear a ring land off. The gap ofcourse has to be even larger for NO2 or FI applications. Worst case senerio you have broke the top ring land off the piston. That's what took the tip of your plug off. I have personally seen this but I don't want to tell you to tear into the motor yet. I would run a leak down test and see what you get.
Chris
Chris
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