Ok so awhile ago i maid a thread asking what can cause the Charge temp to be reading high and figured out there is a hole in the side of piston 8 so yeah my question is what can cause this? I don't think its the tune cause I've been running this tune for a year without any problems. the day it happened i did 2 pulls one from 60-140 another was just first gear then just took it easy on the car on the way back home then when i exited the highway it started to shake and shit. whats weird it no smoke is coming out of the exhaust and no check engine light and no ticking. And do you guys think I'm going to need new Heads? Did compression check throttle close 1-4 had 150psi driver side had 135 psi and 8 had 0 ;(
03 cobra Melted piston8 and melted spark plug..
- Thread starter 5_0coyote
- Start date
Hate to hear that - what was your setup? If you haven't pulled the motor how do you know the condition of the piston - bore-scope?
yup bore scope. and it has a ported blower 2.9 upper 4lb lower stock injectors stock pumps BAP
Hi charge temp means heat which leans to detonation. I bet your temps were high and you detonated. Now whether your tune isn't pulling enough timing w the high charge temps or it just detonated for another reason, but that's what happened. GL on your repairs
I assume no head cooling mod?
Complete opposite charge temp was in 90s before the the pull plus I've raced the car in AZ 100 degree heat and no problem with charge temp being 180 lol.but before these pulls couple days ago i had a insert on that cylinder idk if that affected it or not but yeah.
I think your confusing the two temps. Charge temp or Iat2 is the temp of the air inside the lower intake, not your coolant temp which is monitoring your engine coolant temps. If your using the wording correct and your charge temp or iat2 temps were 180 and your tune isn't pulling enough timing, then yes, your risk of detonation is through the roof. For your charge temps to get that high you lost coolant in that system, coolant not circulating or your ic pump failed.
Then on top of that you make two pulls to 140 with an already poor design for coolant flow in the factory heads (if you still have them and no cooling mod). With the inherent problems with cooling the number 7 and 8 cylinder that spells disaster.
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Sorry dp
this is the vid of the pull https://www.youtube.com/watch?v=GbQZ0TBcyJ0 charge temp bottom coolant top. I've raced this cobra like 5 times in a row with my charge temp being 170-180 and no problems. I think my injector didn't spray fuel and when i put the bore scope through the motor there was a scratch on the piston..
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this is what it sounds like now https://www.youtube.com/watch?v=_iDgjiSqZtc
First off you should do the compression test with the throttle open.
Second based on the way the car sounds, i don't hear a miss, I would recheck compression.
If you had 0 compression on cylinder 8 you should have a noticeable miss.
I am not sure how you could see a hole in the side of the piston with a bore scope?
Maybe you can post a picture of some point.
There have been numerous engine failures after high speed runs in these cars. The piston to cylinder clearance is tight and it's easy to overheat the crown of the piston and gouge the cylinder wall.
I highly doubt you will need new heads, you may need new valve guides and reground valves and seats. If you have damage it's going to piston/cylinder damage. Especially if you have a hole in your piston like you are saying. You're talking about a bottom end rebuild at that point.
Second based on the way the car sounds, i don't hear a miss, I would recheck compression.
If you had 0 compression on cylinder 8 you should have a noticeable miss.
I am not sure how you could see a hole in the side of the piston with a bore scope?
Maybe you can post a picture of some point.
There have been numerous engine failures after high speed runs in these cars. The piston to cylinder clearance is tight and it's easy to overheat the crown of the piston and gouge the cylinder wall.
I highly doubt you will need new heads, you may need new valve guides and reground valves and seats. If you have damage it's going to piston/cylinder damage. Especially if you have a hole in your piston like you are saying. You're talking about a bottom end rebuild at that point.
Yep that's the typical damage you see with these cars. You overheated the piston and the crown expanded into the cylinder. Probably caused by your high speed run. You have to rebuild the motor at this point. That means new pistons and rings. The cylinder's will need to bored .10 or .20 over. You will need to deck, and align hone the block as well. You will need new bearings (mains, and rod bearings) and all new gaskets. You will need to re-balance the crank for the new pistons. I would turn the crank as well. You will need new head studs and head gaskets, I highly recommend ARP head studs. You will need to resurface the heads. You may or may not need a valve job. I doubt you will need new heads. When you do a rebuild make sure you do the cooling mod if you don't already have it.
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