aAZz

So last night went to Tucson to do a couple little runs. Car ran great towards the end of the night car started running like it had a misfire but no check engine lights came on. Took plugs out this morning and looks like I melted one of the tips. Put new plugs in but car is still misfiring. Any of you encounter this problem or what do u guys think it could be?

Unreal

Ring land, cracked block, head gasket.

Friend at 1/2 mile did same thing on first pull. Plug melted. Looks like a piston let go.

aAZz

I've seen that but then I've also heard it can be something as simple as me not getting enough fuel. Maybe my fuel pump is taking a ****

The_Nigel

I've seen plugs break like that and the sharpnel gets caught in the valve seat and cause a misfire. That's the lucky way out usually it's much worse.

neverstop

there are some cheap borescopes you can get online that work with your phone that are pretty good at looking for carnage

aAZz

Yea i tried renting one out from our local auto parts store but they didn't have one so ended up doing a compression test cyl 4 has 0 pressure so pretty sure there was a party going on in there. So now might just throw a l33 in there and really party

CI GS

Do a compression check and that will most likely confirm this^^^. Maybe your fuel pump took a **** and that's what caused the damage that is now causing the misfire. A bad fuel pump isn't going to cause a miss at idle, but it will cause it to lean out at WOT, which is what will cause the damage that will cause it to misfire. That plug doesn't just have the ground strap torched off, the porcelain insulator around the center electrode is gone too, most likely from a piece of the piston being pounded against it. Not good. Some of the other plugs look bone-white too, which would tend to confirm this. Hope it's not too bad and you can salvage the motor.
EDIT: take a good close up HD picture of the plug and see if it has molten aluminum on the end of it. It sort of looks grey in your pic, but it's hard to tell from that angle and distance.

Ant-Man

I didn't melt a plug but I have the same thing going on, ran fine but now it runs like trash and sputters anywhere below 3k.

aAZz

Fuel pump is good tested it with a fuel pressure gauge last night. Primes to 51psi and when on it stays consistent. Just gonna pull the driver side head tonight so I can stop taking guesses and really see what's going on.

Unreal

Who tuned it? Setup? Fuel setup?

Probably ran lean, or just a bad tune. In all the time dealing with LS motors and TONS of tuning I've never had a plug melt.

aAZz

Nicd tuned it. With how my set up was throw together I can't really blame tuner as Nic told me that if I was gonna beat the **** out of it too throw some unleaded 100 in there for safety. Couldn't get ahold of any sat night so tried my luck and wasn't on my side.
6.0 with btr stage 2 n/a Cam
Aps tt kit
60# injectors on stock pump with BAP tuned for 91

Unreal

Beating on any car out here on only 91 is a recipe for killing a piston.

Good luck on the rebuild.

aAZz

Yea lesson learned. Got a lead on a l33 shortblock might just throw that in there for now with a legit cam and get her up and running and if block isn't damaged too bad build this on the side. With a l33 and a legit boost cam I can def turn it up and have some fun with it for way cheaper lol

Unreal

At least throw a can of torco in if going to beat on it or race. Easy to keep in trunk and add when needed.

aAZz

Yea just gonna buy a couple gallon of 100 and keep them at home for special occasions like last weekend.

aAZz

Well looks like I lucked out. Pulled passenger head and it was a valve issue. Pistons look good

Pekka_Perkeles

Bent valve or spring issue?

aAZz

Springs look good. Valve issue for sure.

Unreal

I would be taking a close look. Vavles don't magic just stop sealing when a plug melts. I would bet the valves are a victim of something else.

Would very very very closely inspect that cylinder for a cracked liner. Also the piston may not be in one piece, or have a cracked ring land. You may not be able to see that from where you have it now. I would drop that one piston out for sure for an inspection.

aAZz

Yea i'm debating if I should take whole motor out and inspect it or just slap on some 317's that I have laying around and let it eat. It doesn't look like piston hit valve tho as there is no scratches or dents. I'll turn the motor over by hand and see how the walls look and go from there I guess