Stripped flywheel bolt!

[Turbo_Rampage]

Hello, When i was putting the flywheel on my rebuilt motor last winter (for my Rampage) I found one of the flywheel bolts holes was stripped out when i started torquing it to spec! I managed to torque it to 25Ft/lbs and i put lots of loctite on it and it seems to be holding just fine.. but now the clutch is starting to get weak and i want to upgrade to an Aluminium flywheel, TII/TIII clutch and now will be a nice time to fix it properly. What are some options on fixing this? Could i use a Heli-coil? Has anyone else had this problem? Oh its an 86 block so it has 8 flywheel bolts if that makes a difference.

Thanks in advance:thumb:

[WVRampage]

Id talk to a machine shop and ask them I would inset it but i dont know what kind of problems that would or wouldnt cause.

[supercrackerbox]

I have had the same problem and did use a Helicoil. The insert was somewhat difficult to locate, it is 10mm x 1.0, very fine thread. Now I was lucky, and had the engine out of the car when this happened. Doing the repair in the car I think would be a bit more difficult.

First off when you drill the hole, take off the oil pan. The bolt holes do go into the crank case and you will get metal shavings in there. Stuff a rag or something behind the flange, just make sure it doesn't catch and bind on the drill bit. I also recommend removing the seal housing, as shavings have a tendency to collect inside the lip of the seal.

Second, you have to drill it STRAIGHT. Rather than starting out with the drill bit for the kit, I started with a couple sizes smaller and progressed upwards so I was just barely scraping the hole each time. Finally after you've got the hole drilled, it's time for the tap. Always use cutting oil when tapping cast iron. Don't just screw it in there, you have to work it back and forth the whole way to avoid chipping your new threads. When that's done, clean the hole really well with some brake clean, and install the insert as per the instructions. Coat it with red Locktite.

Now you're ready to reassemble. Any more questions, feel free to ask.

[Turbo_Rampage]

I have had the same problem and did use a Helicoil. The insert was somewhat difficult to locate, it is 10mm x 1.0, very fine thread. Now I was lucky, and had the engine out of the car when this happened. Doing the repair in the car I think would be a bit more difficult.

First off when you drill the hole, take off the oil pan. The bolt holes do go into the crank case and you will get metal shavings in there. Stuff a rag or something behind the flange, just make sure it doesn't catch and bind on the drill bit. I also recommend removing the seal housing, as shavings have a tendency to collect inside the lip of the seal.

Second, you have to drill it STRAIGHT. Rather than starting out with the drill bit for the kit, I started with a couple sizes smaller and progressed upwards so I was just barely scraping the hole each time. Finally after you've got the hole drilled, it's time for the tap. Always use cutting oil when tapping cast iron. Don't just screw it in there, you have to work it back and forth the whole way to avoid chipping your new threads. When that's done, clean the hole really well with some brake clean, and install the insert as per the instructions. Coat it with red Locktite.

Now you're ready to reassemble. Any more questions, feel free to ask.


Thanks for the info! Is that Heli-coil (10mm x 1.0) the same bolt size as the other flywheel bolts? I am going to remove the motor/trans just because its easier to pull it all at once. Plus i might let a machine shop do this..

Thanks again:thumb:

[supercrackerbox]

The Heli-Coil, when installed, will result in perfect 10mm x 1.0 internal threads.

[Turbo_Rampage]

Hey, I am finally ready to Helicoil the stripped flywheel bolt. I have the motor pulled for the T2 conversion, and new clutch, so it should be alot easier to do with the motor on a workbench.. I had a hard time locating the 10mm x 1 Helicoil kit, but after a day of searching i got one. Is their any other good tips on installing these things? I also got an oil pan gasket set, rear main seal, RTV and anerobic sealer. I will get the 13/32 drill bit and a few sizes smaller like you said above.. Are these Helicoils pretty easy to install? Will i be able to torque the bolt down to 70ft/lbs without pulling the Helicoil out?

Thanks

[86Shelby]

They aren't too bad to install as long as you do it according tot he instructions. The helicoil will hold that 70 ft lbs no problem as long as it's installed correctly.

[supercrackerbox]

Just take your time and follow the instructions, you'll do fine.

[Turbo_Rampage]

Thanks for the replies, :thumb: I will be doing this Helicoil tomorrow, and hopefully i can have the motor/trans back in sunday night, and have it running next weekend.. I will let you know how it goes.

[Turbo_Rampage]

Just take your time and follow the instructions, you'll do fine.


I got one question.. Did you have to trim the Helicoil down any? Are was the crank thick enough to hold the whole Helicoil?

Thanks. Randy

[turbovanman²]

It should fit entirely inside the crank as the crank is thick enough. You can get various lengths so make sure all of it will fit inside. Its ok if its a bit shorter. Make sure you seat the heli-coil inside the front, so none sticks out, then use a small punch and hammer to break off the little tang. When you install it, you should coat it with liquid teflon sealer as oil will seep thru if you don't. When you put the flywheel bolt in, don't use Loctite, just use some more sealer.

[Turbo_Rampage]

Thanks for all the replies! I have it finished, and the motor and trans is back in with the complete T2 setup and T2/T3 clutch. It should be running next weekend.. thats if i get my MP stage II GLHS LM in the mail, :(

I will post up some pics of the engine bay next weekend, :thumb: