How does this keep happening

[Dusten]

There's no sign of detonation on the top of the piston. Most likely the detonation happened in the ring groove. Under boost weak spark will cause the ring groove to fill with fuel. Getting out of boost causes accumulated fuel in the ring land to detonate, breaking the ring land.

There doesnt need to be visinle detonation for a knock sensor to detect it.

Detonation bad enough to destroy a ring land will be visible as knock retard

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[robmustang201528]

The second box of spark plugs I've put in that car. After the cat failed it replaced the spark plugs again. I don't know which side of the piston the ring land was broken. I don't know if its the intake valve side or exhaust valve side. I forgot to mention I have the 18 intake as well

 

[Chainsaw]

Don't rule out a weak coil. I'm speaking from experience. I broke a ring land in hole #7. Roush determined it was from weak spark. I had a new long block installed along with new plugs and a new coil on cylinder 7. Running the same Roush tune and all is well now. Good luck.

 

[robmustang201528]

How do they test the coils?

 

[robmustang201528]

Do you think the 18 intake has anything to do with the issue I'm having? IMRC are locked out. And what does that mean anyways? IMRC locked out? I one point I heard people getting 18 intakes that were cracked. We checked for cracks on the intake and didn't see any

 

[Chainsaw]

I don't think they tested the coils. Roush determined it was weak spark by looking at pictures of the piston. I doubt the 18 intake had anything to do with it. IMRC's are the valves in the intake runners. Locking them out locks them in the open position.

 

[Dusten]

The second box of spark plugs I've put in that car. After the cat failed it replaced the spark plugs again. I don't know which side of the piston the ring land was broken. I don't know if its the intake valve side or exhaust valve side. I forgot to mention I have the 18 intake as well

is the damage to the piston on the left side or the right side when the arrow on the piston is facing you?

 

[Crackerjack17]

Looks just like my 2 pistons that cracked the ringlands. #7 and 8 on mine. My rings were intact. Never had a check engine light ever. How i knew something was wrong was because #1 the engine felt "soft" and down on power. #2 massive amounts of crankcase blowby coming out the pcv system.

My guess is massive amounts of heat in my case and likely a little detonation too. I was around 10 psi on average.

I rebuilt the engine with an mmr 1200 shortblock. Dropped the compression to 10:1 And added the head cooling mod.

It runs awesome now, currently on my same setup as before. Except, I dropped a couple pulley sizes because I could with the lower compression. I have over 5000 miles on it and ZERO knock. I spin to 7.5-8k. The thing revs so fast if the tires spin, I can barely make it to the next gear.

There are a lot of factors at play. You can't blame one thing.

 

[Crackerjack17]

Do you think the 18 intake has anything to do with the issue I'm having? IMRC are locked out. And what does that mean anyways? IMRC locked out? I one point I heard people getting 18 intakes that were cracked. We checked for cracks on the intake and didn't see any

So you didn't install the intake? The factory intakes have what amounts to flaps that fold down right where the intake meets the head and makes the hole smaller. This promotes increased velocity at low rpm and increases torque. "Locking" them open means just that. On the back of the intake you disconnect the vacuum mechanism and physically hold the arm so it can't move. Some use zip ties or a custom bracket. Why do you want them open all the time? Because the intake wasn't exactly designed to be pressurized and i guess some were having trouble with them closing or making the hole smaller as boost built which would obviously restrict flow. Which would be bad at high rpm.

 

[Excel]

detonation ..could be tune,ring seal,butting rings, fuel dist issue,lean or too rich
and if I had my engine apart I would add forged piston and upgraded rings

 

[Tommy V]

E85 a band aid lmao,he is running a torque booster,so basically he is tlrunning full.boost through the whole gear in every gear,which generates alot of heat.10 pounds of boost dont mean shit if u dont know what timing he is running,what if its 18 degrees.Basically need to see a log before anyone can say,but running 93 on these cars on boost usually ends up in running really conservative timing or damaging the motor know matter who tunes it.I would get rid of the torque booster.

 

[kcc0521]

Funny how people are so quick to blame the tune even when it is a reputable tuner with hundreds of not thousands of similar tunes on the road. What about the possibility of a faulty watergate causing car to over boost. Could also be weak fuel system. Or just really long WOT passes in warm weather. With wastegate IATs must be pretty high.

 

[bluebeastsrt]

I'm with you. The one guy who is adamant about it being the tuner. Is the one guy still running the stock tune? There is a ton of process variables that could have doomed this engine. How is a tuner supposed to know if a coil died. Or a plug fouled after he tuned the vehicle? Once you move up to a power adder. You gotta pulled the plugs and inspect them every few thousand miles. I had to inspect the plugs in my 95 race car after every nitrous pass. To insure a variable didn't change.

 

[Dusten]

I'm with you. The one guy who is adamant about it being the tuner. Is the one guy still running the stock tune? There is a ton of process variables that could have doomed this engine. How is a tuner supposed to know if a coil died. Or a plug fouled after he tuned the vehicle? Once you move up to a power adder. You gotta pulled the plugs and inspect them every few thousand miles. I had to inspect the plugs in my 95 race car after every nitrous pass. To insure a variable didn't change.

My point was why was the knock not spotted on a datalog? He had sent logs to lund. Lund shouldve seen that kind of detonation.
A lot of issues couldve gone wrong, but 99% are easily seen on datalogs.

Weak fuel system? Car would require more fuel commanded than normal for his setup. His car isnt some exotic setup.

The logs I send my tuner are identical to how its driven to avoid any issues.

He pulled the okugs and replaced them, so two motors, two different sets of plugs.

 

[Dusten]

Funny how people are so quick to blame the tune even when it is a reputable tuner with hundreds of not thousands of similar tunes on the road. What about the possibility of a faulty watergate causing car to over boost. Could also be weak fuel system. Or just really long WOT passes in warm weather. With wastegate IATs must be pretty high.

What does a wastegate have to do with iat?

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