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Discussion Starter #1
Hi Supraforums family,

Is it okay to use exhaust manifold bolts without a washer or lock washer? Or, will they eventually back out or cause problems when the meta expands. I don’t have studs for all the exhaust manifold holes, so I just want this to work, but be safe too.

251371
 

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I would use studs and nuts in all spots. You can start the nuts with the header away from the head and gradually tighten them as you push the header in. I wouldn't trust bolts because they can be pushed at an angle by the header and possibly mess up the threads.

I suppose bolts could work in a pinch. The only reason I changed my tune is it looks like you already have the darn thing installed, lol! So it's too late at this point to worry about changing it.

Al
 

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OP,

Your using Hex flanged bolts which is better than using a bolt without any flanges or washers, because there is more friction lock on the two mating surfaces.

The factory studs/open flanged nuts are more preferred for exhaust manifold hardware as it easier to remove when needed as the exposed threads are easier for penetrants to work into.

Hard to say as I haven't had experience with anything other than the OEM hardware, but if your in a pinch, I'd start with making sure the bolts are torqued to 29 ft/lbs per TSRM, and follow their bolt tightening procedure to reduce the chances of manifold flange warping as much as possible.

Hope it helps
 

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Discussion Starter #4
I appreciate everyone’s input. I bought some studs from Rock Auto, but they seem too short. One of them barely fits with the nut (no washer). Do you guys think this one will be okay? (It came with thread locker already on the stud.

251411
 

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With no science or "proof" behind me, I would think it should work. I would likely be looking at it after your first drive, and then periodically after that (?every 100 to 200 miles?).
 

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If you already had the bolts tightened, I wouldn't have changed it. Do they not sell stock Toyota parts in your neck of the woods? The stock gasket is pretty hard to beat. I would have also checked if the studs were available.

Al
 
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