Xmas Posted October 24, 2007 Share Posted October 24, 2007 I have two broken studs on the passenger side exhaust manifold. I saw that Casey mentioned that I should put on the Thorley headers. ~ Now if i was to put on the new thorleys hedders will this remedy the known exhaust manifold bolts breaking issue?? ~ I know that hedders will increase HP, but I am happy w/ the Pathy-power I have in the stock 3.0, I just don't want to hassel w/ these darn manifold bolts ever again. Thanks!! Link to comment Share on other sites More sharing options...
msavides Posted October 24, 2007 Share Posted October 24, 2007 There is much debate on this. Many people say that the defect is weak studs. Some say the defect is in warping exhaust manifolds. Could even be a combination of both. I never wanted to ever do it again, so I replaced everything. I even switched from studs to locking bolts, I have never needed to touch them since not even to re torque them. some people have replace the exhaust manifolds or even had there old ones machined flat again and have had no more problems. I did not want to take a that chance. Headers will also make you engine compartment a little cooler. Mark I have two broken studs on the passenger side exhaust manifold. I saw that Casey mentioned that I should put on the Thorley headers. ~ Now if i was to put on the new thorleys hedders will this remedy the known exhaust manifold bolts breaking issue?? ~ I know that hedders will increase HP, but I am happy w/ the Pathy-power I have in the stock 3.0, I just don't want to hassel w/ these darn manifold bolts ever again. Thanks!! Link to comment Share on other sites More sharing options...
unccpathfinder Posted October 24, 2007 Share Posted October 24, 2007 There is much debate on this. Many people say that the defect is weak studs. Some say the defect is in warping exhaust manifolds. I'm pretty sure the studs break then the manifold warps...if you dont replace the broken studs and then put thorleys on I'm pretty sure with time you will warp those as well...as metal (and most objects) heats up it expands and depending on the temperature it can change grain structure when it cools this also changes the properties of the metal so if it is not bolted down properly the metal will deform (warp)... change the bolts to some good grade 8 studs and get the manifold machined or get throleys and a good gasket and you wont have to worry about a leak Link to comment Share on other sites More sharing options...
Xmas Posted October 24, 2007 Author Share Posted October 24, 2007 good to know. So since I have NO-IDEA how long these exhaust manifold bolts were broken, I am sure the manifold is warped, you think? So I just need to go to a machine shop to have them even it back out? What do you recommend? The engine is coming out this weekend, so I need to make sure my honey-do list is up to-date Thanks all! Link to comment Share on other sites More sharing options...
Gotrek Posted October 24, 2007 Share Posted October 24, 2007 good to know. So since I have NO-IDEA how long these exhaust manifold bolts were broken, I am sure the manifold is warped, you think? So I just need to go to a machine shop to have them even it back out? What do you recommend? The engine is coming out this weekend, so I need to make sure my honey-do list is up to-date Thanks all! It'd personally go with Grade 5 Bolts over Grade 8 Studs. Grade 8 material has a different expansion/cooling rate then the heads/manifolds do and will likely cause problems. Grade 5 should expand at about the same rate. Link to comment Share on other sites More sharing options...
Casey.T Posted October 24, 2007 Share Posted October 24, 2007 good to know. So since I have NO-IDEA how long these exhaust manifold bolts were broken, I am sure the manifold is warped, you think? So I just need to go to a machine shop to have them even it back out? What do you recommend? The engine is coming out this weekend, so I need to make sure my honey-do list is up to-date Thanks all! PM Answered... If your going to have the motor out.... easy access to the broken studs and perfect time to replace all of them and upgrade the exhaust manifolds to Thorleys..... DO IT!!!!!!!!!!! Link to comment Share on other sites More sharing options...
Tungsten Posted September 28, 2009 Share Posted September 28, 2009 It'd personally go with Grade 5 Bolts over Grade 8 Studs. Grade 8 material has a different expansion/cooling rate then the heads/manifolds do and will likely cause problems. Grade 5 should expand at about the same rate. What size are the bolts and do they have to be specialty bolts? Link to comment Share on other sites More sharing options...
unccpathfinder Posted September 29, 2009 Share Posted September 29, 2009 pull one out and get the right length from the parts store...but I can't reember off the top of my head...i used the studs but i think bolts will be fine Link to comment Share on other sites More sharing options...
SteeevO Posted September 29, 2009 Share Posted September 29, 2009 I personally like the studs because they have the ability to use more threads in the head. they really don't go in very far so i like to use as many of the threads as i can. I've been running thorleys for a few years now and i haven't had a broken stud since. Link to comment Share on other sites More sharing options...
Toby Posted September 29, 2009 Share Posted September 29, 2009 You need to relocate the oil filter to install thorleys correct? Link to comment Share on other sites More sharing options...
Tungsten Posted September 30, 2009 Share Posted September 30, 2009 You don't have to but it is recommended because its harder to get to the oil filter with the headers. Link to comment Share on other sites More sharing options...
edicer2 Posted September 30, 2009 Share Posted September 30, 2009 one way i fixed it i me and my mechanic got supper strong bolts(dont remember the guage) that thread into the head like the orignals and then took the orginal manifold and had it planed flat. The reason i did this is because the orignal one wont warp as much as what a new one that hasnt already warped before. Plus the stronger bolts will allow it to take more of a stress and not have them snap or leak. worked good for me! never had a problem again Link to comment Share on other sites More sharing options...
cdhicks99 Posted September 30, 2009 Share Posted September 30, 2009 I know this has been beat to death.... however I have searched and searched and cannot find the correct part number for the Thorleys. Also any suggestions on where to get them at a reasonable price? Link to comment Share on other sites More sharing options...
Precise1 Posted September 30, 2009 Share Posted September 30, 2009 Everything you ever needed to know on this page, courtesy of... me!!! http://npora.ipbhost.com//index.php?showto...&hl=thorley B Link to comment Share on other sites More sharing options...
cdhicks99 Posted September 30, 2009 Share Posted September 30, 2009 Thanks B. I promise I'm not lazy....just impatient Link to comment Share on other sites More sharing options...
Precise1 Posted September 30, 2009 Share Posted September 30, 2009 LOL No worries, I knew what I was looking for, now go get those headers!!! When I called, Thorley had some in stock so I basically got them in 2 weeks (although that seemed slow). B Link to comment Share on other sites More sharing options...
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