Is it possible to overtighten exhaust manifold bolts? A family buddy came over and helped me install this APN manifold (actually a header, really) but we didn't have a torque wrench, nor do I think we could have reached a few of the bolts with one if we had. So we just hulk tightened the suckers from the center out. Certainly that is more pressure than the recommended torque settings but can it hurt anything?

 

....YES... you can and probably did overtighten them.. When it gets hot it can crack if overtighten to much. Get a torque wrench!! Like ten bucks at HF dude!

 

i should add that the APN header has a thicker flange than the manifold at certain points so if I tighten some bolts the exhaust will be tighter than the intake. Does this make sense?

 

You can't really get a torque wrench on the bolts anyway. I think the book calls for 24 ft lbs on all the bolts. The two nuts I don't remember. I just put about 20 ft lbs on them and then another 1/8 of a turn. They don't need hulk tightened down. Doing that can mess up the block.

If you guys were hanging or putting all your weight on the wrenches then you should go back and redo all the bolts.

Torque them down correctly cold, drive it for a week, then recheck torque because they may loosen. Mine did not.

 

I think I remember what you mean.. haha.. As long as you were not grabbing the jack handle for a breaker bar and you just used the socket ,I think you should be alright.. I installed an APN on my XJ after cracking the exhaust manifold but was able to reach all the bolts but one with socket elbows to use the torque wrench. The last bolt I just felt how hard it was to slightly turn one I had already torqued and then tried to replicate it.

To counter the problem I think your talking about... I took out all the exhaust and intake bolts and started fresh torquing them all to the same spec.

As far as hurting anything? You could cause cracks in the intake/exhaust manifold under high temps if it is THAT tight..

 

We used no breaker bars, but we did put some force on them. I just dont see how you got a torque wrench to some of them. I'm kinda worried now :X

 

Better safe than sorry man.. I know it is a PIA though.. It would be even worse if you end up having to buy another one though!!

As far as getting to them with a torque wrench.. I think I used like 2-3 different elbows and extensions and if was not for the cold beverages, probably would have said screw it, but was able to torque all but that one. Got a couple from under the Jeep as well..

 

Do it right or do it twice...

 

Your lucky they didn't break. Not fun

 

nooooo. I was never worried about doing that. We only got them small socket wrench tight, and on the ones where we couldn't get even a socket just closed end wrench hand tight.

 

The second you add an elbow to a torque wrench, it no longer works properly.

You can add an extension as long as its still at a 90 degree angle but elbows that change length make the wrenches readings inaccurate. For that matter, a long extension will screw the reading unless you hold it at a perfect 90 degree angle, tilt it and your readings are off.

 

You're fine as long as you used a short wrench or ratchet and got them "forearm" tight.

I've never used a torque wrench on them in 27 years, never broke a bolt or stud, and they never backed off.............

 

Yes - which will cause uneven gasket compression, screw seizure (in this case,) and probably warped flanges (due to grossly uneven clamping force.)

I wouldn't get a $10 HF special - good measuring tools are worth spending at least a little money on. (When I was taking Auto Tech courses to make what I know official, we had access to a calibrator. Short form? My Craftsman clickers were just as accurate as MAC and Snap-On clickers, and the cheaper stuff you may as well use a "turn and pray" method.)

If it's a measuring tool with moving parts, spend some money to get a good one.

 

if nothing broke I'm sure you're fine. it's not an AL head so you prob couldn't do enough damage with a 3/8 ratchet and limited working space to fret over.

 

You guys put any locktite on them? Like the blue?