Hello all, am new to this forum (first post), but not new to the Cobra. We have an '04 Comp Orange that has been in the family since new. The car has an interesting history I will share in another post. On Sat I was driving casually and heard a thump from the front of the car, followed by a much louder thump under the car. I initially thought I had run over an animal, when I spotted something on the road in the rear view mirror. The car was still running and I pulled over and turned it off, walked back and found the pulley assembly sitting in the middle of the road. The good news it appears there is no other major damage, but I have not had a chance to get under the entire car to see where it hit (it hit somewhere). This is a first for me on any car. I was just under it a month ago changing the oil, but would never have thought to inspect the HB screw. So now I get to replace and install both pulleys in the near future. It is not a daily driver so not in a hurry. The engine was rebuilt about 10yrs ago due to a piston failure so that is the last time the HB would have been off the engine (there are several mods). The crappy stock crankshaft pulley pulley was replaced with the Metco Pulley kit (much better than the awful stock set up) after it failed in 2012. Has anyone experienced this? Thanks for any info. Skene
'04 Cobra - Harmonic Balancer and Crank Pulley fell off
- Thread starter SRBCitrusCobra17
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So you've had 2 lower pulley failures since 2012?
Whomp whomp
Now that I'm on a computer. Honestly, that shit should NOT be able to come off. It has to be "pressed" on (not really pressed with a press but lack of a better word it doesn't just slide on) plus the snout bolt, plus the belt keeping it on to a degree. Unless you're belt is really misaligned walking the pulley off which whould most likely throw the belt instead I have no clue how that could come off. Plus then where did the bolt for the crank go? I'd get that on ASAP, change the seal in the process cause probably messed that up on the way off. The pully should not just slide on. Also I wouldn't be suprised if the Metco pulley is damaged now. I'd do some digging and carefully check everything before you have really big problems with shearing the crank key, etc.
I know of one other pulley that came off a Cobra. Similar to your issue. It was the Metco lower and the bolts holding it to the crank pulley sheared off. But the inner crank pulley was still in place.
I don't know that I'd call the stock set up horrible. A lot of guys would rather keep it due to the cage supporting the crank snout.
I don't know that I'd call the stock set up horrible. A lot of guys would rather keep it due to the cage supporting the crank snout.
My balancer bolts sheered right off recently on my Coyote. Have no idea how but I replaced them with stronger chromoly bolts. Probably didnt torque them properly when I put the new balancer on I guess. What a dope!
My balancer bolts sheered right off recently on my Coyote. Have no idea how but I replaced them with stronger chromoly bolts. Probably didnt torque them properly when I put the new balancer on I guess. What a dope!
Are 5.0's different? On a 4.6 it's a single bolt into the snout.
OP, did you have ARP hardware? Did you re-use the bolt. IIRC you're not supposed to re-use them. Is the bolt snapped in the crank or just missing?
Yea, two bolts and they tie into the AC compressor.
No, I went to the nutty bolt store and got some high tensil strength ones. They were just snapped hanging around in there vibrating making a sound like I had a knock in my motor. Very relieved it was the balancer believe me.
No, I went to the nutty bolt store and got some high tensil strength ones. They were just snapped hanging around in there vibrating making a sound like I had a knock in my motor. Very relieved it was the balancer believe me.
The crank end looks and feels ok. Surface is smooth, hole for the screw appears to still have loctite residue so yes a single screw in the CS. Bolt does not appear to have snapped off in the crank. Presumable this is a left hand thread. I was not involved in the rebuild so not sure if the old bolt was reused. I think at the time of the rebuild the car only had about 12kmi on it, has 24kmi on it now. The block is the original 4.6 punched out to 5.0. Damage to one cylinder resulted in the bore over. The stock pulley was replaced due to rubber mounts in the pulley failing if I recall. The Metco pulley was fine (until it hit the asphalt).
Pardon my neg comment about the stock pulley set up. IMO there should be no rubber mounts between the pulley and the hub....that is what failed along with the bearing it was riding on, and it is heavy. I agree the extra support does seem to be a plus. The Metco set up is certainly cleaner, and lighter. Yes I am very puzzled how this could have happened. With ~90ftlbs on the bolt and a pressed fit this should stay on forever. I should mention the motor not stock. Including the bore kit it has a Kenne Bell SC, cams, headers. It has been a "fun" car for my father and his blind friend and currently sees << 1k mi annually.
maybe you can post up some pics of the damage. it sure does sound like a very unusual failure, because even with a metco lower, the harmonic dampener would have had to come off very quickly and all at once while you were driving on saturday.
even if it had been working its way off gradually over a period of time (due to no washer on the crank bolt), both belts would have walked off long ago.
do you know the svt build number and build date of this comp orange? was your dad the original owner? welcome
even if it had been working its way off gradually over a period of time (due to no washer on the crank bolt), both belts would have walked off long ago.
do you know the svt build number and build date of this comp orange? was your dad the original owner? welcome
My theory is the bolt had worked its way loose and came off at some point previously. I drove the car on Friday morning and had to hard brake to avoid a deer, this was a full white knuckle event. My theory is that event was the straw that broke the camels back and shifted the HB forward a bit. The next drive on Sat was all it took to finish the job. It came off shortly after I had stopped at a stop sign There was no warning....it just happened. Speed was approx 35 - 40 on a back road
I believe there were 281 Comp Orange Cobras built in '04. We have all the documentation, but I don't recall the build#. My dad and his blind friend purchased the car new back in 2004 new in Loveland CO. His blind friend is a former master mechanic who wanted to relive the good old muscle car days. He likes the thrill rides. Current\y the car is in Loveland CO where my father lives. I live in Chandler, AZ and travel up there monthly. Working from home has its benefits. Below are some pics (hopefully they post). Not a good close up of the crank shaft, but obvious something is missing.
I believe there were 281 Comp Orange Cobras built in '04. We have all the documentation, but I don't recall the build#. My dad and his blind friend purchased the car new back in 2004 new in Loveland CO. His blind friend is a former master mechanic who wanted to relive the good old muscle car days. He likes the thrill rides. Current\y the car is in Loveland CO where my father lives. I live in Chandler, AZ and travel up there monthly. Working from home has its benefits. Below are some pics (hopefully they post). Not a good close up of the crank shaft, but obvious something is missing.
You're 100% positive the crank snout is still in place on the front of the motor? Can't see it or tell from the pics because of the water pump pulley being in the way. The only thing that makes sense with the belt being intact and it happening as quickly as it did is if the snout finally gave way!
Crazy!!
Crazy!!
Yes indeed this is crazy. The snout looks intact, there was some residual grease on it from presumably when it was installed. The surface was smooth and the notch for the pulley looked ok. Have not validated the condition of the threads on the crank shaft yet.
Just for the hell of it, try to slide the balancer/dampner pulley back in place! See if yours had extra clearance that allowed it to slip on and off the crank snout by hand.
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