Summary of blown engines Cobra motors

[juno]

Yeah, it seems most of these motors are blown for a reason, and it's not because it was a bad motor.

[Warpath]

#7 too lean is the most common failure I've read. #8 is the second leanest. Both of those pistons cracked on my OE engine. One theory is that the TB and intake tubing is on the right side of the engine (opposite MMs). Therefore, the airflow path is a straight shot into those two cylinders whereas the airflow has to make a bend to get to the other cylinders. It seems to make sense.

It seems that most tuners tune to get max hp and not longevity because max hp gets them more business and that's what the customers want. Lidio tunes for longevity. I got less hp than I was expecting. But, he explained my expectations were based on these "unsafe" tunes and I would likely have to replace the engine again if I got what I expected. So, I agree with the statement above that the engines were pushed too far.

[merc]

This list was copied from ModularFords.com. It gives you some idea about problems that Cobra owners are having. They have blowers and better lower internals then we have stock, but far from bullet proof. Enjoy the read you might find some of the facts interesting.

The full story (http://www.modularfords.com/forums/2003-2004-svt-cobra-terminator/summary-of-blown-engines-12489.html?highlight=overheati ng)

mustang500hp (Stock): Galled #2 piston suspect due to low piston clearance. Failed at 2k mi.

03RedCobra (Stock): Blown head gasket, filled all the cylinders up with fluid, and it had to be replaced. It was BONE stock, even down to the filter. Failed at 1,700 mi.

RedSquad7 (Stock): Thrown rod at 1,286 mi!

smytty001 (Stock): Piston #7 damaged at 2.7 kmi. Stock except for CB.

John1975 (Eaton 2.93” upper, x psi, 433/_ rwhp/tq): Suspect blown #2 piston. Failed after 3 high-speed (135-155 mph) runs. A/F = 10.9-11.7:1 right up to redline. Octane = 94. K&N FIPK. Engine failed at 3.5k mi. Modded for 1.5k mi.

RedSquad7 (Eaton w/ 2.93” upper, 13-14 psi, 459/456 rwhp/tq on DJ): 2/4/05. 2nd Engine. Burned piston #2 after high-speed run (155-160 mph) during which several vacuum lines came off. A/F = 12.0-12.2:1 (at tailpipe). Octane = ?. Total timing = ?. 9” open K&N. Stock fuel sys. Bassani catted X and CB. Modded for ~2 kmi. Predator custom tune. Engine failed at ~10 kmi.

Z-06_Killa (Eaton 2.8” upper, 12.5(?) psi, 470/501 rwhp/tq DJ, 508 rwhp MD w/ N2O): 5/23/05. Piston #2, cyl and head damage. Lead came off spark plug, causing damage to piston...piston fatigued in that location/possible clogged injector. Detonation was heard by passenger in other car @ 120+mph before it let go. A/F = 12:1 blower, 11:1 N2O. NGK BR7EF plugs gapped at 0.032”. Octane = 93. Total timing = 23 deg blower, 20 deg N2O. Prochamber, Magnapack CB. CAI. Failure at ~22k mi. Modded at ~15k mi.

Copperhead - SVTP (Eaton 2.8” upper, _ psi, 430/400 rwhp/tq now): Low compression on cylinder #7 & 8. A/F = 10-11.5:1. Octane = _. _ Plugs. CAI. Offroad X-pipe and CB. _ chip. Engine failed at 43k mi. Modded for ~6k mi.

AnonymousT1 (Eaton 2.8” upper, 14 psi, 478/485 rwhp/tq): Minor scoring to #3 piston skirt, no other signs of damage mechanical damage. Accelerated hard with less than 1/8 tank of gas and blew fuel pressure sensor - car developed knock immediately after. A/F = 11.8:1 at peak power. NGK TR6 plugs gapped at 0.035”. Octane = 93. Magnaflow catted X & Steeda CB. SFPHQ CAI, Accufab TB. Failure at 12k mi. Modded at 7k mi.

ptrfree (Eaton, 2.8”, 13-14 psi, 444/435 rwhp/tq): 7/10/05. All exhaust valves on left head burned. Pistons OK. A/F = 11.5:1. Octane = 93. Timing = ?. TR6 0.032”. K&N 12” CAI. Catted H, Magnaflow CB. Engine failed at 37 kmi. Modded since 2 kmi.

calithekid (Eaton, 2.76”, _ psi, 435/453 rwhp/tq): 5/27/05. Knocking sound noticed during street race. One bad piston occurred at ~140 mph and missed shift -> over reved engine. Custom dyno tune, Magnaflow CB, JLT CAI, 5000 mi at time of failure. Motor replaced under warranty.

Grey03Cobra (Eaton, _ psi, 483/503 rwhp/tq): Piston (heat) damage to #7 & 8 occurred after top end high speed run (160 mph). Bassani X, CB & Mid-Length Headers. UPR CAI. Diablo chip. Engine failed at ~18k mi.

deadcobra (Eaton 2.8" upper, 12 psi, 450 rwhp): Failed at 4,800 mi, mods for 3,000 mi. Damage 7 piston burned other 2 pistons damaged, 2 broken rods, damaged crank and slight block damage. Suspect due to tune being too lean.

NeedForSpeed03Cobra (Eaton 4# lower, 2.8”(?) upper, _ psi, _/_ rwhp/tq): Heat damage to 3 pistons (#6, 7, & 8). Suspect due to a vacuum leak causing a lean condition.

Kino (Eaton w/ 3.1” upper 6# lower, 17 psi, 473/_ rwhp/tq): Heat damage to pistons and scuffs on skirts on 3 of them. Damaged pistons appear to be undersized. Blown head gasket. A/F = 12.1:1. Denso IT-22 plugs gapped at 0.030”. Octane = 93. Stock induction system. Stock fuel system. QMP 3” exhaust w/ CATs. Diablo chip. Engine failed at 27.5k mi. Modded for 21k mi.

tommygun (Eaton 2.8” upper, 14 psi, 456/458 rwhp/tq): Piston #7 broke from top down to the ring land resulting in no compression. Failed when racing at > 150 mph. Detonation noted at time of failure. Octane = 91. A/F = 12.2:1 at peak power. NGK TR6 plugs. 11,235 mi when failed (700 mi after tick fix). 5.6k mi modded. Also had exhaust and CAI.

|RageATM| (Eaton 2.75” upper 4# lower, 17 psi, 457/517 rwhp/tq): Heat damage to all pistons, the worst was #2 followed closely by #7 & 8. Suspect new tune caused a lean condition, but A/F was not checked. (Initial tune had A/F = 11.8:1). NGK TR6 plugs. Octane = 93. CAI. Stock fuel system. VRS Catted midpipe and Magnaflow CB. Engine failed at ~16k mi. Modded for ~3k mi.

olchakla (Eaton w/ 2.8” upper, 15 psi, 458/460 rwhp/tq DJ): Spun #3 rod bearing, scored #6, and #8 was discolored. Suspect oil starvation. BBK Twin blade 65 mm TB, Stock MAF. Stock fuel system. Magnaflow catted-X and CB. Diablo chip. Engine failed at 24k mi. Modded for 12k mi.

3snakes1coupe (Eaton w/ 2.8”/4#, 17 psi, >500/? rwhp/tq DJ): 4/26/05. Low compression on 7&8. Heat damage to several pistons & scored skirts, and heat damage to head. A/F =12:1. Total timing = 23 deg. Octane = 93. NGK TR6 plugs. Aftermarket HE. BBK TB, MAFXtender. KB BAP. Magnaflow catted X and CB. Engine failed at 2k mi. Modded for ? mi.

capnkirk52 (Eaton 2.8” upper, _ psi, 330/330 raw (@7645 ft) rwhp/tq on M.D.): Scored skirts of all 8 pistons. Cause unknown, (too much heat, back-to-back dyno runs, 160MPH blast?) A/F = 11.5-12.0:1. Stock plugs. Octane = 91 w/ octane booster. K&N FIPK. Stock fuel system. Bassani O/R X and CB. Total timing = 19 or 22 deg. Engine failed at 3.8 kmi. Modded for 2.3 kmi.

capnkirk52 (Eaton 2.8” upper): Second failure. Teflon on all pistons scored. Suspect result of heat from high-speed runs. Same equipment as before plus Accufab TB and Bassani mid-length headers. Failed at 8 kmi.

Zinc03Cobra (Eaton w/ 2.76” upper, _ psi, _/_ rwhp/tq): Broken right-side head timing chain. NGK TR6 plugs. 12” open K&N. Magnaflow CB. Bassani O/R X. Custom Predator tune. Failed at 21 kmi.

SALEENGTROUSH (Eaton w/ 2.8” upper, _ psi, _/_ rwhp/tq): Heat damage to piston #7 & #8 is scored. Many (>50) high-speed (upwards of 160 mph) runs. Heard detonation during run when it blew. UPR CAI, Mac O/R-H and CB, Custom Predator tune.

sndmn_2000 (Eaton w/ 2.8” upper, _ psi, _/_ rwhp/tq): Ran lean causing piston damage (scuffed) on #7 and #3. Tune not checked (ouch)! CAI, exhaust. No other info.

SonicSlowbra (Ported Eaton w/ 2.8” upper, _ psi, 490/473 rwhp/tq SAE DJ): Broken piston skirt #7. Suspect timing and heat related. A/F = 12.5:1. NGK TR6. Octane = 93. K&N FIPK. Stock fuel system. XMS HE. Catted X and SLP CB. Diablo chip. Engine failed at 3.1k mi on 9/20/04. Modded for 350 mi.

wjfawb0 (Ported Eaton w/ 2.8” upper, 14-16 psi, 491/471 rwhp/tq SAE): ~10/1/05. No pressure in cyl #2. In the last few months I had the FPDM fail, which may have damaged the pistons due to random dropping fuel pressure. A/F = 11.5-12. NGK TR6. Octane = 93. Timing = 18. K&N FIPK, Accufab TB and plenum. Dr. Gas O/R X-pipe, Magnaflow CB. Engine failed at ~61 kmi. Pullied since 4.5 kmi.

lucafu1: (Ported Eaton, 2.76” and 3#lower, 16 psi, 531/520 rwhp/tq): 4/05. #2 piston skirt, overheated (after piston skirt May 2005) warped heads, busted radiator, expansion tank and cap. Suspect damage from heat. A/F =12.0. Octane = 93. Denso 22 0.032”. Total timing = 22. Extreme H/E, Apten head cooling mod. JLT RAI w/ SFPHQ MAF adapter/10" power stack, SCT BA2400, Accufab T.B. KB BAP w/ 60# injectors. MRT Gutted Cattted H-Pipe, Borla Stingers. Engine failed at ~11 kmi. Miles since modded = 800.

bross03cobra (Ported Eaton w/ 2.8” & 4#, 15 psi (@5,500 ft), 100 dry shot post MAF, 650/815 rwhp/tq SAE DJ): Broken piston #2. 100 N2O passes, 100 blower only passes, 106 dyno pulls(!!). A/F = 11.1:1 w/ juice (11.5 w/o). Autolite AR103 at 0.032”. Octane = 91 on street (w/o spray) or 103 for track. Total timing = 18 (w/ juice) or 21 (w/o juice), KB BAS. Steeda CAI, Accufab TB and inlet, SCT2400 MAF. KB BAP, 60# SD inj. LPF HE, Apten cooling mod. JBA shorties, Magnaflow catted X and CB. Diablo chip. Engine failed at 18.5 kmi. Modded since 900 mi.

[DEFYANT]

Yup. Lifes a *****. You want to play? You may have to pay.

[martyo]

Blow motors are a fact of life in high hp applications. Get used to it.

[merc]

Blow motors are a fact of life in high hp applications. Get used to it.

Maybe you didn't get my point or read the link that includes the full tread.
There is more information to be questioned then blown motors. I found this comment on the second page. It is interesting the arguments that were created by this tread. Some of these issues were covered on this site also.



Were any of these cars that had a engine give because of lean conditions tuned on a Mustang Dyno or another dyno that loads actual weight???

Heres what more then likely happen'd (let the conversing begin):

More then likely you guys all had your car tuned on a Dynojet were close to maxing out your fuel system and when you actually pushed your beast of 4,000lbs that one more time you didnt have enough fuel...........why............ ...........because a Dynojet isnt loading your car to a real wieght once those things get spinning they have alot less energy put on your motor then would normally be seen by your car.

Maf close to being Pegged or is Pegged on a dynojet when your on the real road is running lean.
A fuel system running almost max duty on a dynojet is not giving you any room for real world conditions.....ie uphill load/running over 140mph/racing with 3 people in the car.

Do you guys really think that a Dynojet is giving your car the best tune for the way you drive your car in extreme conditions??????????

IF YOUR CAR IS MAXED OUT ON DYNOJET YOUR CAR IS GOING TO FRY.
PERIOD.
__________________
Tampa whipple killer.

I also have to agree that these factory engines are being pushed way beyond their intended duty cycle. I also feel that a lot of these cars are not adressing the pegged maf issue. At those HP levels, a pegged maf in the right conditions of load can spell disaster. Burned pistons because of overheating/lean conditions added to the driverside head having coolant circulation issues is magnifying the problem. People who are persuing these high hp levels should use caution and move up to return style fuel systems, maf meters that have the extended range of operation, and use common sense and realize that a production block is not bullet proof.............. :smoker
__________________

[martyo]

Maybe you didn't get my point or read the link that includes the full tread.
Their is more information to be questioned then blown motors. I found this coment on the second page.


Mark: We weren't on the same page. Sorry. I hope I didn't offend you here.

[MarauderMarc]

So what I am getting here is that: 1, dont use a tuners "box tune", and 2, have an expert like Lidio tune it correctly rather than some schmuck doing it improperly? Am I understanding this right? What tuners have a bad "out of the box" tune? Thanx for the insight.

[jstevens]

Exactly. Tune to the max and expect trouble.

[Breadfan]

Agreed, if you're not looking to be a race only car that will require a rebuild from time to time it's not the way to go.

Having a few HP is nice, sure. Getting top notch numbers is cool too. But sometimes a few HP is not worth a certain amount of money.

I mean, is 20hp or so really worth an $8k rebuild?

So long as my cars are driven and I don't feel like pulling the motor I'll stick with the safe tune.

The only time I'd go for a max tune would be just to get my bragging numbers, then I'd back it down for street use. ;)

[Warpath]

I'm not saying that all tunes are bad. They need careful thought. Just pick someone you trust. But, personally, I prefer dyno tunes since your vehicle is monitored while its there. If you have something different about your vehicle than the box tune was based on, they can compensate for it.

[Petrograde]

IF YOUR CAR IS MAXED OUT ON DYNOJET YOUR CAR IS GOING TO FRY.

I'm glad I had mine tuned with a Mustang Dyno! :P

[Blackened300a]

Ill be hitting the Dyno this Saturday and have them do it the right way. Like was Said Before and couldn't be more Correct


20 or so HP isnt worth the $8k rebuild

[Warpath]

Mustang Dynos are not automatically the preferred dyno. The parameters need to be set up properly. I don't know what parameters are available. But, I would image it could be possible to set up a Mustang Dyno to act just like a Dynojet. Like I said, go with someone you trust. Lidio tunes with a Dynojet.