Preventing Broken Exhaust Studs
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Senior Member
Joined: Oct 2000
Posts: 755
The exhaust studs are subject to large and frequent heating cooling cycles, and so lose their clamping tension over time. This is like a piano going out of tune. So what happens is that over time fewer studs are doing the work of clamping the manifold to the head. Everytime you hit the gas or throw a shift, causeing the engine to rock on its mounts these studs are being stressed. The ones doing the work break first. The harder you drive your car, the faster they break.
What you want to do is get all the studs working again. The way to do this is to re-torque the nuts. Since many of the nuts are probably frozen, to some degree, spray some penetrating oil on them first. "Crack" the nuts lose (aside from starting at a common torque value, this should also avoid breaking a "fatigued" stud), then retighten them in stages (like a cylinder head). Even if you just use an open end wrench (to avoid taking things apart) this is better than nothing.
What you want to do is get all the studs working again. The way to do this is to re-torque the nuts. Since many of the nuts are probably frozen, to some degree, spray some penetrating oil on them first. "Crack" the nuts lose (aside from starting at a common torque value, this should also avoid breaking a "fatigued" stud), then retighten them in stages (like a cylinder head). Even if you just use an open end wrench (to avoid taking things apart) this is better than nothing.
The only way to prevent broken studs is to take them off before they break and replace them w/ the 300z versions. The original ones are weak. The rest of mine were tightened down but the end one still broke. (front and back side)
Originally posted by brubenstein
The exhaust studs are subject to large and frequent heating cooling cycles, and so lose their clamping tension over time. This is like a piano going out of tune. So what happens is that over time fewer studs are doing the work of clamping the manifold to the head. Everytime you hit the gas or throw a shift, causeing the engine to rock on its mounts these studs are being stressed. The ones doing the work break first. The harder you drive your car, the faster they break.
What you want to do is get all the studs working again. The way to do this is to re-torque the nuts. Since many of the nuts are probably frozen, to some degree, spray some penetrating oil on them first. "Crack" the nuts lose (aside from starting at a common torque value, this should also avoid breaking a "fatigued" stud), then retighten them in stages (like a cylinder head). Even if you just use an open end wrench (to avoid taking things apart) this is better than nothing.
The exhaust studs are subject to large and frequent heating cooling cycles, and so lose their clamping tension over time. This is like a piano going out of tune. So what happens is that over time fewer studs are doing the work of clamping the manifold to the head. Everytime you hit the gas or throw a shift, causeing the engine to rock on its mounts these studs are being stressed. The ones doing the work break first. The harder you drive your car, the faster they break.
What you want to do is get all the studs working again. The way to do this is to re-torque the nuts. Since many of the nuts are probably frozen, to some degree, spray some penetrating oil on them first. "Crack" the nuts lose (aside from starting at a common torque value, this should also avoid breaking a "fatigued" stud), then retighten them in stages (like a cylinder head). Even if you just use an open end wrench (to avoid taking things apart) this is better than nothing.
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Joined: Aug 2000
Posts: 615
with only 97k on my '93 Se with the VE30DE engine, and with no broken studs yet, should I be looking into replacing them before they break? what i'm most worried about is them breaking while replacing them because I reaaly dont have the means to have my car sitting for more than a day. are the studs susceptible to breakage while removing them cold?
I would say if you have some engine or exhaust work done, it would be a good time to get the studs replaced at the same time. If they are not broken, unscrewing them should not be a problem. Check w/ the alldata website and check to see if your year includes a TSB for broken exhaust studs. My 92se had problems but maybe they fixed in the later years. I doubt it though.
Originally posted by RosenKen
with only 97k on my '93 Se with the VE30DE engine, and with no broken studs yet, should I be looking into replacing them before they break? what i'm most worried about is them breaking while replacing them because I reaaly dont have the means to have my car sitting for more than a day. are the studs susceptible to breakage while removing them cold?
with only 97k on my '93 Se with the VE30DE engine, and with no broken studs yet, should I be looking into replacing them before they break? what i'm most worried about is them breaking while replacing them because I reaaly dont have the means to have my car sitting for more than a day. are the studs susceptible to breakage while removing them cold?
once you get far enough into things to replace the studs, if one breaks while you're changing them, it'll only take about 10-15 minutes to drill one out.
when you take them off, I suggest a GOOD coating of Aerokroil or liquid wrench, then elt them sit for 1/2 hr or so, then go back and spray them again and let them sit another 10 min or so.. they should come loose pretty easily that way.
when you take them off, I suggest a GOOD coating of Aerokroil or liquid wrench, then elt them sit for 1/2 hr or so, then go back and spray them again and let them sit another 10 min or so.. they should come loose pretty easily that way.
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