Broken secondary timing chain tensioner bolts

Quade

Old Man.
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Guys, this is the second time I've had to deal with this so I thought I'd share this time just in case there is someone else that has the unfortunate experience of this in the future. There is quite a few of us running high HP and torque now-a-days so I figure the more amount of tech we can get out will just help us all.

About 3 months ago, just after my car went into Failsafe mode from breaking a pin in my MAFia, I could hear a rattle in the top, passenger side of my of my motor. I broke out the old screwdriver stethoscope and pin pointed it in the front of the head and began pull the valve cover and this is what I found.

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I was pretty relieved to find the tops of the bolts still in the valley in the head and not disappeared down a drain back hole. Just some light rubbing on the chain and gears (enough to polish them) was the only other damage. I removed the cam gear bolts, zip tied the chain to the gear and slid the gears off about half way, just enough to be able to **** the tensioner sideways and started drilling.

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A couple hours later I had the bolts extracted and I drilled the heads of the new bolts for safety wire just in case, in the unlikely event, it ever happened again......lol. I got the new bolts installed and torqued to the Ford specs and then safetied them.

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I put it all back together and changed my oil, started the car to let it warm up and then chainged oil again. All was well.........Up to last night and after a pass, the same chatter came back. Keep in mind, my car hit Failsafe last weekend about 4 times due to the Supercharger Bypass valve being completely destroyed. :xpl:

This is where I'm at now. Notice the difference in the position of the tensioner in both pics. At least the safety wire held the bolts in the tensioner this time.

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I cut the safety and pulled the bolts right out.

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Tomorrow I'll drill them out and I'm going to over size them this time and possibly stud it this time. I'll update as I progress.:beer:
 

Van@RevanRacing

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Time to upgrade to Ford GT and/or Navigator Timing Chains and gears. Sucks you are having to deal with this. Only way to handle the power.
 

IronTerp

Mid-Atlantic Cobra Assoc.
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Wow. Interesting. Real nice writeup and explanation Jammye. Looks like you've averted some potentially bad damage. Now we know what nearly 1,000 RWHP will do to a weaker link in the chain.
 

Quade

Old Man.
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I just turned over 16000 mile on this motor and this is the only problem so far and now it's happened twice. I'd say you're right Dwight, I've pushed this car as hard as I can, so far, and it owes me nothing. If this this is the worse that happen until next year, I'll be ecstatic. I think I'm gonna go with a few more cubes next year lol.

Van, my chains, guides and gears look exceptional on that side. The bolts are the problem and they are getting ready to be double the size here in an hour or so. When I go 5.8, it will definitely have the Navi rig on it. Got a kit put up.

I'll post more pics here shortly. I've got one bolt already extracted and working on the other.
 

Quade

Old Man.
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OK, just got the broken bolts extracted and I'm ready to start the upsizing next. First thing I did was to back the cam gear bols out just enough to slide the gears off as far as I could without them sliding off the cam snout. I zip tied the chain to the gear just incase the primary gear came off the snout, it wouldnt jump a tooth.

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Then I prepped her for the lobotomy. I cleaned the entire area with Tri-Free and taped it off with Gorilla Tape. The sheared face of the bolt was a little rough so I took the Dremel tool and cleaned up the rough edges so I could get a good, flat surface to center punch.

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The first on came out as I was drilling with the reverse thread drill bit, but the second one required the ease out.

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This is what I'll be going back with. The small one is one of the origional bolts that i bought extra of when they broke the first time and they're grade 8.

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I'll probably wait to drill and tap the new holes tomorrow and I'll update again as soon as I do. Gotta get my set of reamers from work.
 

Rob_03Mach

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hey Jammye, are the original bolts torque to yield bolts? Just curious, they look like the same bolts used on the 07 OEM clutches that had issues... Also Steve, took the words out of my mouth, try ARP bolts?
 

Carlos c

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Great work, thanks for sharing.
What does the Ford GT/Navi parts consist of and what is the difference?
 

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