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2G Harmonic balancer bolt just came out.

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Could you explain further on this? I'm not sure why this is.

I cant give you the exact science on it, but I'm sure it has something to do with the way the torque is applied to the bolt and the surface area. Try taking one off for the first time using just the 1/2 extension insert. It's not gonna happen.

I actually tested it on my girlfriends car recently with a Milwaukee 1400 ft/lb off torque impact just to see if it could do it. It actually cracked the head of the bolt before it even budged. I put a socket over it and it zipped right off.

Given my experiences with trying to get those bolts off with the extension only, and the fact the only time I ever had one back out was when I torqued it with the extension only, I'm sure there is a reason.
 
To set things straight here, Kurt's point is a good one. I would rather have one hell of a time removing a timing gear that I don't think I ever need to remove, than have one come off in the fashion that mine did. I am not one to say, well, I'm always right.
In my case, I am going to follow his suggestion of using a LIGHT amount of locktite to help "glue" it and the bolt on. I don't know the reason why mine backed out, but just about everything on this car has come loose at one time or another due to vibrations.
So, just because the FSM doesn't say it, doesn't mean it isn't good insurance for $2100 worth of head parts. Thanks @bastarddsm for your advice!
Marty
 
To set things straight here, Kurt's point is a good one. I would rather have one hell of a time removing a timing gear that I don't think I ever need to remove, than have one come off in the fashion that mine did. I am not one to say, well, I'm always right.
In my case, I am going to follow his suggestion of using a LIGHT amount of locktite to help "glue" it and the bolt on. I don't know the reason why mine backed out, but just about everything on this car has come loose at one time or another due to vibrations.
So, just because the FSM doesn't say it, doesn't mean it isn't good insurance for $2100 worth of head parts. Thanks @bastarddsm for your advice!
Marty
Can I assume most guys reuse the crankbolt that was originally on their car? All my builds to date recieved new crank bolts and washers and were lightly oiled on instAllation. This was after chasing and cleaning the threads in the crank with a thread CHASE not tap before installation. I just dont see a crank bolt coming loose when installed correctly. Every crank bolt ive ever removed was a hassle without a impact. On a side note.... has anyone ever had a bolt come loose from a car that was still unmolested? Id imagine not. Seems like most failures are caused by insufficient torque related to lubrication or some other variable.
 
I can only speak for me. New Eagle crank and new Arp center bolt that looks fine. Crank threads are visually fine also. Crank gear keyway elongation is twice as wide as it should be compaired to a new pulley keyway. Crank snout seems to have survived, timing gear has wear compaired to my new pulley. Originally no locker and 85 lbs. No balance shafts and new original OEM balancer. If I could say why mine worked loose, I'd gladly share it, but this is not a normal DD, I turn her 9k all the time.
I wonder how many have went out and at least checked there's just to be sure after this thread, LOL? Anyone???
Anyway, just sharing.
 
I can only speak for me. New Eagle crank and new Arp center bolt that looks fine. Crank threads are visually fine also. Crank gear keyway elongation is twice as wide as it should be compaired to a new pulley keyway. Crank snout seems to have survived, timing gear has wear compaired to my new pulley. Originally no locker and 85 lbs. No balance shafts and new original OEM balancer. If I could say why mine worked loose, I'd gladly share it, but this is not a normal DD, I turn her 9k all the time.
I wonder how many have went out and at least checked there's just to be sure after this thread, LOL? Anyone???
Anyway, just sharing.
Is it possible that because the crank and crank bolt you used are made out of different material you should use different torque specs? Does arp give you torque specs with the bolt? Like mentioned above I think most guys assume stock torque specs apply for everyone. Even at 85 ft/lbs you'd think it would be sufficient. Is the bolt length and washer thickness the same as oem? Im curious
 
They are the same, well probably harder material, and ARP didn't come with special torque specs. My engine harmonics/total car harmonics have been notorious to loosening things on it. I am willing to bet anyone watching this thread went out and checked theirs and some, or at least one, probably found the same. I am going to keep it on by adding locktite, because, as Kurt and you both mention, we are doing more than just stock stuff. I don't want to pull threads in a Eagle crank but I have come to not mind giving that part a little help staying on to save the money it tore up. The pictures of all of that tore up stuff....valves, broken rocker, gouged cams, etc....just had to laugh about how it all came to happen over this one bolt and move forward...(gets welder out, heads toward new crank pulley.....LOL) :p
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Just kiddin.
 
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I have just gone through the exact same problem. Crank sprocket bolt self-loosened ruining a recently refreshed head and many other expensive parts. Bent all 16 valves, gouged cams, destroyed lower timing cover, Gates blue timing belt and balance shaft belt. I begin putting it all back together tomorrow, now that all my new parts are in. ~$2000.00 due to one bolt loosening itself.
 
They are the same, well probably harder material, and ARP didn't come with special torque specs. My engine harmonics/total car harmonics have been notorious to loosening things on it. I am willing to bet anyone watching this thread went out and checked theirs and some, or at least one, probably found the same. I am going to keep it on by adding locktite, because, as Kurt and you both mention, we are doing more than just stock stuff. I don't want to pull threads in a Eagle crank but I have come to not mind giving that part a little help staying on to save the money it tore up. The pictures of all of that tore up stuff....valves, broken rocker, gouged cams, etc....just had to laugh about how it all came to happen over this one bolt and move forward...(gets welder out, heads toward new crank pulley.....LOL) :p
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Just kiddin.
You think thats funny? I actually DID weld the cam gear to the camshaft on my Audi/VW 1.8t for that very reason. Fresh head on car, drove for one day, came to a stop sign and the bolt loosened and the junk powdered metal gear sheared the keyway and bent valves, well lets just say 150k miles later it never happened again.
 
Its enough to make ya cuss aint it. I'll be over 2100 on this so sometimes ya no....
Vibrations man....
Mine held until it broke the keyway btw...
 
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