Did my plenum replacement over the weekend and ended up replacing the intake manifold bolts with standard grade 5 automotive bolts from the store and torqued them to 12 lbs per the FSM. Am I ok?

 

you shoulda asked this on the weekend

 

I did. I asked a mechanic friend and he said it was fine, although I wanted to ask the forum since there is a ton of experience on here.

 

Should have used Red Locktite on them as well.

 

I just find it ironic that you spend the money on a kit that fixes a bad seal issue, only to skimp out on the fasteners that are crucial in preventing the seal from going bad again.

you will probably be OK.

 

Well I did ask a mechanic if I would be ok using regular bolts and he said yes. I used TTY bolts for the actual plenum gasket/plate that came with the APC kit.

I am really just trying to either confirm what I was told or find out if I should replace the bolts with TTY bolts?

 

My take on it: If the standard bolts are not so long that they are bottoming out, the threads were clean and free of oil, and you used high quality gaskets, then check the torque on the cold engine after the first run cycle that reaches full operating temperature, and again on the cold engine after the fifth full temperature run. Don't back them out even a little bit, and don't apply any more than enough force to reach the specified torque value. Just to be sure, I'd check them again in about a month. After that, forget all about 'em.

With TTY's re-torqueing is a no-no, but with standard bolts it's a requirement.

Ultimately, what we're shooting for in intake manifold mounting is enough clamping force to provide a reliable seal, applied uniformly over the gasket area, but not so much force that thermal cycling causes stress fractures.

So just recheck the torque on those bolts and be happy. And on the up side, if the day comes when you have to remove the manifold you won't have to worry about those bolts snapping the way TTY's do.