Care To Share How You Broke ?

[Jam421]

I understand this is not a pleasant topic but was wondering if folks shared how / why they broke a motor , clutch , rear, axle etc.... it could be educational . Was it too much HP ... too much HP/PSI on pump gas ....poor choice in cam swap ....rev too high ....AF or poor plug choice ....should've installed a BAP ?
Was the final result a refreshed engine or kick butt fully built race motor ?

I'm on my 3rd clutch in 11K miles. Stock clutch went at 4K miles after I had the car a few months. I had no idea that would happen but right there on the dyno at 650rwhp GONE. A few times I suspected too many " stupid" launches with TC ON was the culprit. Either way when it cut loose game over. Replacement was Spec II Twin. But I'm convinced the shop that did the install on my '13 did not do the required proper alignment computer flash because 4K later one quadrant on my outer disc was worn to the steel ! Otherwise the clutch & slave looked looked brand new. Of course next step was a New shop.
McCleod RXT, ALFW, new slave, proper install + flash without a hitch in almost 7K miles.
But after spending $6000 they were very expensive lessons !

 

[RBB]

Never heard of any sort of flash being involved with a clutch replacement, that's a new one to me.

My stock clutch was toast at about 30K miles. I'm surprised it made it that long. Just general wear and tear and quite a few launches at the track.

I just had my rear diff rebuilt a couple of months ago. The race around my passenger side carrier bearing exploded at the track. Ring and pinion actually looked pretty good. Axle splines were a little twisted on both sides, passenger side more than driver's. Replaced everything in there including an axle upgrade. New ring and pinion, bearings, seals (they were trashed from all the metal floating around in there), new axles, Ford Racing G2 cover and a Swarr Bar. Hopefully that holds up for a while.

I hope I never have a blown motor story. I'd imagine it's not a question of if I'm going to pop it at this point, just when. Doing a build this fall so I don't have to worry about putting a rod through the block.

 

[RedVenom48]

Bent the stock set of axles trying to hero launch at the track. Got the rear brake squeak of doom. Put a set of take off axles back in, but im saving for a Strange 35 spline conversion with 9" ends.

The extra couple tenths a hero launch may get you in the 60ft isnt worth damaging a car that will STILL hurt a lot of feelings past the 60ft.

 

[Snoopy49]

Never heard of any sort of flash being involved with a clutch replacement, that's a new one to me.

From the 2013-14 Service Manual concerning the replacement of the clutch.

After completing the repairs, use the scan tool to perform the Misfire Monitor Neutral Profile Correction procedure, following the on-screen instructions.

Profile Correction
Profile correction software is used to learn and correct for mechanical inaccuracies in the crankshaft position wheel tooth spacing. Since the sum of all the angles between the crankshaft teeth must equal 360 degrees, a correction factor can be calculated for each misfire sample interval that makes all the angles between individual teeth equal. The LDR system learns one profile correction factor per cylinder (that is, 3 correction factors for a 3 cylinder engine or 4 correction factors for a 4 cylinder engine), while the HDR system learns 36, 40 or 60 correction factors depending on the number of crankshaft wheel teeth (that is, 35 for some V6 and V8 engines, 39 for V10 engines and 58 for some I4 and V6 engines).

The corrections are calculated from several engine cycles of misfire sample interval data. The correction factors are the average of a selected number of samples. In order to assure the accuracy of these corrections, a tolerance is placed on the incoming values such that an individual correction factor must be repeatable within the tolerance during learning. This is to reduce the possibility of learning incorrect corrections due to crankshaft velocity disturbances.

Since inaccuracies in the wheel tooth spacing can produce a false indication of misfire, the misfire monitor is not active until the corrections are learned.

Two methods of learning profile correction are used. The first is neutral profile correction and non volatile memory and the second is customer drive cycle for profile correction 97 to 64 km/h (60 to 40 MPH deceleration).


Neutral Profile Correction And Non Volatile Memory
Neutral profile learning is used at end of line to learn profile correction through a series of one or more neutral engine RPM throttle snaps. This allows the misfire monitor to be activated at the assembly plant. A scan tool command is required to enable neutral profile correction learning. Learning profile correction factors at high speed (3,000 RPM) neutral conditions versus during 97 to 64 km/h (60 to 40 MPH) decelerations optimizes correction factors for higher RPMs where they are most needed and eliminates driveline or transmission and road noise effects. This improves signal to noise characteristics which means improved detection capability.

The profile correction factors learned at the assembly plant are stored into non volatile memory. This eliminates the need for specific customer drive cycles. However, misfire profiles may need to be relearned using a scan tool procedure if major engine work is done or a new PCM is installed. Relearning is not required for a reflash.

On selected vehicles, the neutral profile correction strategy is the only method used for profile correction learning. In the event of a loss of non volatile memory content (new PCM installed), the correction factors are lost and must be relearned. The P0315 DTC is set until the misfire profile is relearned using a scan tool procedure.

Customer Drive Cycle For Profile Correction (60 To 40 MPH Deceleration)

To prevent any fueling or combustion differences from affecting the correction factors, learning is done during deceleration fuel shut off (DFSO). This can be done during closed throttle, nonbraking, defueled decelerations in the 97 to 64 km/h (60 to 40 MPH) range after exceeding 97 km/h (60 MPH) (likely to correspond to a freeway exit condition). In order to minimize the learning time for the correction factors, a more aggressive DFSO strategy may be used when the conditions for learning are present. The corrections are typically learned in a single 97 to 64 km/h (60 to 40 MPH) deceleration, but may take up to 3 decelerations or a greater number of shorter decelerations.

If the software is unable to learn a profile after three, 97 to 64 km/h (60 to 40 MPH) deceleration cycles, DTC P0315 is set.

 

[Jam421]

Thanks Snoop....that seems like the language used by my shop ->) !

Guys....we all hate these stories. But I recently backed off a mod getting me from 17.5 to 18-19psi simply because I had bad thoughts about it. Plus $2300 for 20rwhp made little sense especially if I feared popping something on 93 octane. Like riding a motorcycle and you dream at night of going down.....horrible ! But that's me.
I've blown 2 motors in Cobra Kit cars . Many lessons learned but I always saved longer than upgraded. Like I mentioned above I can't say if my stock clutch blowing was due to previous owner or my stupid show off day dropping lines forgetting TC was ON.

 

[RBB]

From the 2013-14 Service Manual concerning the replacement of the clutch.

Thanks Snoop....that seems like the language used by my shop ->) !

Guys....we all hate these stories. But I recently backed off a mod getting me from 17.5 to 18-19psi simply because I had bad thoughts about it. Plus $2300 for 20rwhp made little sense especially if I feared popping something on 93 octane. Like riding a motorcycle and you dream at night of going down.....horrible ! But that's me.
I've blown 2 motors in Cobra Kit cars . Many lessons learned but I always saved longer than upgraded. Like I mentioned above I can't say if my stock clutch blowing was due to previous owner or my stupid show off day dropping lines forgetting TC was ON.

The misfire correction not being performed had absolutely nothing to do with your Spec clutch wearing out like that. The vast majority of clutch installs don't have this procedure performed and are fine. You'll know you need it if you start getting random misfire codes after a clutch or lower pulley replacement. You either had a defective clutch from Spec or a bad install.

Probably a good move not going to 19psi....that's pushing it on pump for sure. For an extra 20HP at a cost of $2,300, it just doesn't make any sense.

 

[1st usa car]

nothing so far but came close to feeling broke after some mods
but comparing similar mods on other platforms I felt lucky to spend the money.

 

[JB_2010GT500]

All the failures on my car have been on the launch at the drag strip. Like lexustech said, trying to be a hero. With 18" NT05Rs, I have broken the following parts at stock power level:
- driveshaft
- bent rear axles
- upper control arm

With a Kenne Bell 2.8 and their canned tune for 93 octane and a 3.25" pulley (about 615 whp or so), I broke the following:
- spun axle tube
- bent Moser 31 spline axle

Culprit in all these cases was sticky tires combined with an aggressive launch at the track.

 

[50stangpower]

well my breakage is like so many others. It started with a track trip so the night before i was on my local concrete bridge using launch control with about 670RWHP. The next day I went to the track with R88's and tried launch control on my second pass. still went a 2.1 60' (only 2nd pass in the car). The third pass on my 2-3 shift my clutch was toast. As soon as I put it in gear my RPM's went to redline and my car wasnt accelerating. I though I did a 1-2-1 and broke the trans. I barley limped it down the return road. Black dust was everywhere and I had to get pushed into my trailer. The factory clutch went from 100% to 0 in less then a second.

 

[2veloce2003]

Same here (2003 Cobra) All the failures on my car have been on the launch at the drag strip

Clutch
Rear axles 2x - stock and upgrade

 

[gimmie11s]

Interesting to hear about all of the bent axle and spun tubes.

Guess its good i welded my axle tubes during my swap from 3.31s to 3.73s.

 

[Black Cobra '99]

Well mine aren't so dramatic nor heroic, lol.
Stock clutch went at 24K miles, I intended to save for a clutch first then I left it and hoped it'll be fine but it didn't. So I drove like a granny for a couple of months until I got the RXT.

The rear pads were shaved completely until the metal dug into the rotors and I had to change them. I already had Hawk pads but when I inspected the pads I thought they were fine, turns out they weren't.

Lastly was Mcleod clutch braided steel line. It started leaking on the transmission end so I returned to stock. After close inspection I couldn't find anything wrong with it and the o rings were fine.

 

[802gt500]

April drag racing at the track got me. VMP 800 hp kit. Combo of cold air and possibly bad gas. Melted 2 pistons 7 and 8. On a sided not after building the new engine with cams, larger valves, larger pistons did multiple data logs with vmp and they said I was good to go. I wanted a remote dyno tune and they said I did not need it. I purchased the remote tune anyway and was very lean on the top end like a 12.5 or so. They corrected the fuel curve and timing and gained 80 rwhp and af was on after that. Firm believer of dyno tuning. Nothing against vmp but hard to do a 160 mph pull in 4th on public roads. Car has been together for a year now and not an issue.

 

[kwarnerjr]

My stock clutch went at 25k miles, replaced with a Spec ST Trim. It died on the track one night, 2-3 shift was close to impossible to preform smoothly.

Bent 2 sets of OEM axles and I am now waiting on the 35 spline diff and axles from Strange. My axles died from aggressive burnouts I believe, at least the 2nd set died from a burnout. The first set could have been a launch or burnout but I try to stay on the conservative side when launching...bent it nonetheless lol

Along the way I also lost an IC pump. The green wire melted in one of the relays causing a failure. Don't know if the pump itself was faulty but I replaced it anyway along with a thicker green wire.


Sent from my iPhone using svtperformance.com

 

[rotor_powerd]

Melted 3 pistons on pump gas. Learned my lesson, the car hasn't had pump gas in it since.

 

[SirShaun]

You guys got me worried, with all that talk of melting pistons. I'm at sea level running 21 lbs 2.4 Upper 10% Lower through a VMP Gen II, on pump gas.

So far only surprise has been shifting an axle tube dry hooking on DRs, and putting the tire into the quarter panel. Replaced with a modded 8.8 - 3.73's, TruTrac, Moser Axles, ARP Extended Studs. Oh and welded the axle tubes.

Stock clutch still going strong at 30k, 520whp -> 700whp for a bit now.

I did have a weird problem with the car coming out of first on hard launches, right before I broke the rear. I haven't been back to the track to see if the new rear fixes it or not. Next I guess will be throwing a clutch, and a MGW at it.

 

[Snoopy49]

One of things that Ford did when they produced the 2013-14 GT500s was the welding of the axle tube to the housing. Evidentially, the added horsepower caused the tubes too rotate in the housing.

2013 Shelby GT500 Chassis Development - Total Package

 

[SirShaun]

One of things that Ford did when they produced the 2013-14 GT500s was the welding of the axle tube to the housing. Evidentially, the added horsepower caused the tubes too rotate in the housing.

View attachment 94964

2013 Shelby GT500 Chassis Development - Total Package

You want to weld where his finger knuckle is, all the way around.

 

[rotor_powerd]

You guys got me worried, with all that talk of melting pistons. I'm at sea level running 21 lbs 2.4 Upper 10% Lower through a VMP Gen II, on pump gas.

You'll be fine until you go to really beat on it on a hot day. When I melted mine, I had my foot on the floor from first until the top of fourth when it went bang, and it was as hot as it is today. I found out after the fact that my IAT protection map was set way too aggressively and it was not knocking timing out like it should have been.