have a stripped thread on camshaft bearing cap

[Tanvir]

Hello ETCG,

Rebuilding the engine of 2000 Toyota corolla for excessive oil consumption. started assembling few days ago and today I was putting the camshafts. Haynes manual says to torque all bearing cap bolts to 120 lb-in except one set which has to be at 17 lb-ft. When I was trying to torque one of those 17 lb-ft bolts, suddenly the thread from the cylinder head stripped. Do not know what to do now. Thinking to tap a larger thread and use and larger bolt. but wanted to consult you before doing so. Please let me know.

Thanks,
Tanvir

Topic

[Bryan Carter]

Here’s the problem with tapping for a larger bolt…

When you torque a bolt, you are actually stretching the bolt to supply a specific clamp load. 17 lb ft of torque for one size fastener does not equal the same amount of stretch/clamping force with a different sized fastener. So you’d end up with an uneven clamping force on your bearing cap. That’s not good.

But here’s what you can do… You probably haven’t stripped out the entire hole, and there’s most likely some good threads left further down. So you may be able to use a slightly longer bolt. Better yet, if you do have good threads at the bottom, you can install a stud instead. You just have to be extra careful that the new bolt/stud is not bottoming out, before reaching the desired torque.

If that fails, the head can be repaired by either welding up the hole and re-tapping, or by installing a Keensert (or similar product). Both methods require a skilled hand and fall outside of the skillset of the average DIYer.

Good luck

[Author]

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