i know alot of people on here have had the tips of plugs go on their nitrous cars. after 1 nitrous run at the track the car was idling with a slight miss, but was fine at WOT. i ran it a few more times, all was well- actually got a new best of 10.93 @ 125mph with a shitty 1.70 (my gears are way too tall).

so i get sick of the miss at idle and i decide to see if the plugs are the problem. find that in one cylinder the tip is completly broken off, with a piece of the porcelain also gone.

i put a new set of tr6's in and start it, still idles with a tad of a miss, and a distinct tapping which sounds like an exhaust leak (was happening since the plug broke on the pass). the tapping is intermittent, like not every revolution of the engine, almost like a noisey lifter but it was never there before.

the car runs GOOD at WOT, no loss of power or anything that i can feel.

question= possible damage to one of the valves or the piston? im not really gonna worry too much about it unless it gets worse. seemed to get a lot better with the plug replaced but still a slight miss at idle.

i was thinking it took a little chip out of the side of a valve, which could be causing the ticking.

thoughts?

 

I had the same problem with mine. It was making a thumping sound through the exhaust. Mine was a little more severe than yours though. It would miss really bad at part throttle. I had burned two slots in the #6 exhaust valve. You may have just gotten a burnt piece of the plug stuck behind the valve in the seat. Do a compression test on that cylinder.

 

compression test for the drivers side cylinders=

1= 145
2= 145
3= 115 (broken plug...)


didn't bother testing any more cylinders.. the car doesn't seem down on power, im probably just gonna keep driving/racing it for the time being. maybe pull that head and see if it is an easy fix or not..

think i'll hurt it more if i make more spray passes? .

 

hmm,
You probley have cylinder going south. Maybe a burnt valve or hurt piston ring. It will only get worse from here... I would not spray it any more. You may be able to limp it around for alittle while.
Dave

 

I had a sparkplug come apart like that and bent some valves.Do a leak down if you can.

 

I bet you hurt the exhaust valve. I would not spray it anymore. You could cause it to backfire and cause further damage. Just pull the head and have it fixed. Mine cost me $60 to fix to include the machine work and valve. I did have a set of headgaskets though. I would hate to see you hurt it worse.

 

what plug were you using? what size shot? timing, fuel octane, fuel pump, etc. might as well take it apart and see whats hurt. its definitely not going to get better by driving it.

 

tr6 plugs, TNT 150 shot, 93 pump, racetronix pump, HP Tuners just dyno'ed. Not sure on timing, I think he had a couple degrees pulled.

 

PS, I wouldnt spray that bish either. Gonna cause hotspots and detonation.

 

yeah im probably not gonna spray it anymore, i did 2 passes tonight because i was pissed about all the work i've recently put into the car and the issues i've been having. felt fine but i know it is only a matter of time if i keep racing it.

i would just hate to yank the head and see piston damage, which is a big mess= yank the motor, pistons, machine work, etc....$$ im praying it is a valve.

thanks for the imput.

 

Denial. I've been there. I was looking through one eye when I pulled my cylinder head. I was relieved to find it only hurt one valve.

 

same thing happened here with me. #6 plug got completely destroyed with me doing the two stage. and that was back in julyish. only misses at idle. hell, i went back to the track and ran my new best on motor with the hurt cylinder. still spraying and even went to the dyno last month. made 475 rwhp with a 100dry/150wet. motor only made 282rwhp.

 

pulled the bottle just now- im gonna yank the head when it gets colder out but the weather is just too nice and i havn't had the car for a while so i wanna drive it/race it. i'll heed the advice given and stick to motor for the time being however.

like mrr23 said, ran it's best spray time with 1/2 of a plug though . can't complain about that. im praying it is a valve, which im optomistic that it is since the miss is pretty suttle and the compression isn't horribly low. just re-tested it and it is 110-115 still after kicking the crap out of it last night.

 

stock timing map! just dyno'd a/f was 11.4 : 1 with a tad of kr on activation, like 1 or 2* at most.

im thinking i hurt the motor right when i hit the button- lean spike.. probably gonna knock some timing back at the lower rpms.

 

Just found out today, that this happened to me. 7 out 8 plugs were burnt. Replaced all the plugs but still runs a little ruff. No noticeable power loss. When I was at the track the engine lost the belt while I was spraying TNT 100 on the stock motor. For a second it wouldn't go past 4400rpm before I knew something went wrong and I lifted. It briefly overheated. Now I'm thinking about replacing the motor but can't really afford it.

 

A few years ago my friend burned a plug in the #4 cylinder. We replaced the plug and the car seemed to run fine. So he sprayed it again and it ended up melting the piston and sleeve in the block.

 

jeez- 7 out of 8 plugs?

mine happened on the first nitrous pass, i made 3 more nitrous passes after it happened- since i thought it closed one of the gaps not burnt the tip of the plug off.

i actually upped the idle to 900rpms to help the miss be less noticable. hope for the best till the weather gets cold, then pull the head and assess the damage