Zmanco Posted July 5, 2010 Share Posted July 5, 2010 I've had a recurring problem with the manifold stud bolts coming loose on the turbo. FYI, the turbo is a Garret T3/T4OE so there is a 1/2" spacer along with 2 metal gaskets - one on each side of the spacer. I'm getting ready to pull the head so I'll have access to them and wanted to know what others have done. When I tore down the stock engine I remember there were 2 pieces of soft metal that were bent up against the bolts to prevent them from turning. This is from the 82 turbo FSM and shows them on the 4 bolts for the downpipe but not for the manifold studs. Should I perhaps be adding them? Also, the five bolts that attach the internal wastegate to the turbine have come loose as well. I'm wondering if this happened because the manifold bolts came loose first, and then the extra vibration worked the wastegate bolts loose? How have the rest of you secured your turbo bolts both at the manifold studs and wastegate? Quote Link to comment Share on other sites More sharing options...
letitsnow Posted July 5, 2010 Share Posted July 5, 2010 Are you using bolts or studs? If bolts, take them out and drill an .040 hole in the head and safety wire them. If studs, use a METAL locking nut, preferably stainless. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted July 6, 2010 Author Share Posted July 6, 2010 I'm using studs. Looks like there are a variety of metal locking nuts: http://www.mcmaster.com/#hex-locknuts/=7ubgxo I see distorted thread and flex-tops. Any significance between them in terms of how well they tolerate vibration? Also, any suggestions for the wastegate bolts? The threads are completely enclosed. Is there any point to using a locking washer or will the heat eventually render it useless? Quote Link to comment Share on other sites More sharing options...
letitsnow Posted July 6, 2010 Share Posted July 6, 2010 I'm using studs. Looks like there are a variety of metal locking nuts: http://www.mcmaster.com/#hex-locknuts/=7ubgxo I see distorted thread and flex-tops. Any significance between them in terms of how well they tolerate vibration? Also, any suggestions for the wastegate bolts? The threads are completely enclosed. Is there any point to using a locking washer or will the heat eventually render it useless? I've used the distorted thread type for other things with success, but I've never used the other types. For a bolt, the best way is safety wire, lock washers don't really work all that well as far as I'm concerned. The problem is that it's such a pain to drill them, you pretty much need a drill press, even then there's a decent chance you'll break a few bits. You can buy pre-drilled bolts, but I seem to remember them being kinda pricey, and I don't remember where. On the other hand, there isn't anything stopping you from making another lock plate with bendable tabs to hold the heads. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted July 6, 2010 Author Share Posted July 6, 2010 On the other hand, there isn't anything stopping you from making another lock plate with bendable tabs to hold the heads. Do you think I can use some sheetmetal such as what I'd get at Lowes? The locking tabs I took off seemed to be more malleable, but I'm not sure where I'm going to find that material around here. Quote Link to comment Share on other sites More sharing options...
letitsnow Posted July 6, 2010 Share Posted July 6, 2010 I don't see why you couldn't, do they have some sort of stainless there? I really doubt the factory used some sort of fancy alloy. Make sure you torque the bolts to the proper spec, none of these methods are meant to hold torque, just to keep it from completely unthreading if it comes loose. Quote Link to comment Share on other sites More sharing options...
johnc Posted July 6, 2010 Share Posted July 6, 2010 I don't see why you couldn't, do they have some sort of stainless there? I really doubt the factory used some sort of fancy alloy. Make sure you torque the bolts to the proper spec, none of these methods are meant to hold torque, just to keep it from completely unthreading if it comes loose. The distorted thread, steel insert lock nuts will probably be your best option. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted July 6, 2010 Author Share Posted July 6, 2010 I'm going to put new studs in: http://www.mcmaster....#studs/=7ueqej. Is general purpose steel acceptable for the exhaust manifold? Looks like steel insert lock nuts aren't available in an M10 but this is: http://www.mcmaster....95a240/=7ugfrc. Is class 8 steel ok for exhaust manifolds? And any reason why I shouldn't also make locking tabs out of shee metal for a belt and suspenders approach? I really don't want to pull the head again for this. Quote Link to comment Share on other sites More sharing options...
Nigel Posted July 6, 2010 Share Posted July 6, 2010 I'm using these: http://www.atpturbo.com/mm5/merchant.mvc?Screen=PROD&Store_Code=tp&Product_Code=MIA-FST-033&Category_Code=FST The nuts work great, and the 14mm head size makes them so much easier to tighten! Nigel '73 240ZT Quote Link to comment Share on other sites More sharing options...
Zmanco Posted July 6, 2010 Author Share Posted July 6, 2010 Thanks Nigel, I called and they have a 57 mm stud that's not on the website so ordered those and the nuts. Perhaps my mistake was using standard non-locking nuts? Interesting that I haven't read of anyone else having this problem. Quote Link to comment Share on other sites More sharing options...
rossman Posted July 7, 2010 Share Posted July 7, 2010 I went with the distorted thread nuts on all my intake/exhaust studs. You will only get a few cycles out of them so use standard nuts if you're like me and like to fit up parts before the final install. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted July 7, 2010 Author Share Posted July 7, 2010 I contacted ATP Turbo and asked them for advice. Here's their response: Studs with copper locknuts on the turbine to manifold and turbine to downpipe joints are about all you can do. When you have fasteners coming loose, don't under estimate the exaust system. make sure it's properly flexed with a decent flex joint so that it absorbs engine shock when the engine is moving and rocking suring driving. Otherwise, all the stress will be transfered to the turbo fasteners and will work them loose. This has me thinking about my exhaust. The downpipe attaches to the wastegate via a 3" V Band. It's a full custom exhaust and it lines up perfectly and it's easy to put the V band on. But perhaps there's enough play in the motor mounts to put stress on it and work the nuts loose? There's no flex joint of any kind. Is this something that is typically required? Quote Link to comment Share on other sites More sharing options...
rossman Posted July 7, 2010 Share Posted July 7, 2010 Is this something that is typically required? OEM's do it and I would say yes if you want your exhaust system to last. How is your exhaust mounted to the car? I used these lock nuts. They're fairly compact. Quote Link to comment Share on other sites More sharing options...
TimZ Posted July 8, 2010 Share Posted July 8, 2010 OEM's do it and I would say yes if you want your exhaust system to last. How is your exhaust mounted to the car? I used these lock nuts. They're fairly compact. I agree - if you are allowing the engine to move on its mounts, then anything that connects to it must be allowed to flex. This doesn't have to be anything terribly fancy - I didn't have room for a 4" id flex coupler, so what I ended up doing was simply putting a section between the downpipe and the "main" exhaust that was only connected by slip joints. This was dead simple, and doesn't leak noticeably. The one caveat is that you have to have enough overlap in the slip joints such that it is held captive between the downpipe and the exhaust and can't fall out. Also, I use the jet nuts linked above for the smaller studs that go between the intake and exhaust manifolds, and they work great - the smaller hex size makes it much easier to get a socket in there to tighten them. They should also work fine for the turbo attachment, although I use something more like the ATP solution. Quote Link to comment Share on other sites More sharing options...
johnc Posted July 8, 2010 Share Posted July 8, 2010 This doesn't have to be anything terribly fancy - I didn't have room for a 4" id flex coupler, so what I ended up doing was simply putting a section between the downpipe and the "main" exhaust that was only connected by slip joints. This was dead simple, and doesn't leak noticeably. The one caveat is that you have to have enough overlap in the slip joints such that it is held captive between the downpipe and the exhaust and can't fall out. Something like this works very well and won't slip out. I build this on all my customer's racing exhausts unless they insist on something different. Quote Link to comment Share on other sites More sharing options...
junglist Posted July 8, 2010 Share Posted July 8, 2010 I'm using these: http://www.atpturbo.com/mm5/merchant.mvc?Screen=PROD&Store_Code=tp&Product_Code=MIA-FST-033&Category_Code=FST The nuts work great, and the 14mm head size makes them so much easier to tighten! I have the exact same nuts from ATPturbo, I also have their studs in the turbo manifold. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted September 2, 2010 Author Share Posted September 2, 2010 Update: I went with the ATP studs and distorted thread nuts and so far they have remained tight holding the turbo to the exhaust manifold. However, after the last track day one of the bolts holding the waste gate housing to the turbine fell out (again!), and another was loose. I think it's time to add a flex pipe and my muffler guy has one ready to install. My question is: where should we put it? FYI, the down pipe is all one piece and a few inches after it levels off we installed a 3 bolt flange. From there the exhaust runs to the rear of the car. It's supported in 2 places: at the rear of muffler in the stock location, and just in front of the rear axle in the other stock location. I figure it either needs to go in the middle of the down pipe, or after the flange under the car. Also, any recommendations on length? He has a 4" and 6" available. I'd prefer shorter, but not sure if that will have enough flex when the exhaust expands as it gets hot. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted September 5, 2010 Author Share Posted September 5, 2010 Anyone with thoughts on where to place the flex pipe? I'm hoping to get it installed on Tuesday. Quote Link to comment Share on other sites More sharing options...
rossman Posted September 5, 2010 Share Posted September 5, 2010 Anyone with thoughts on where to place the flex pipe? I'm hoping to get it installed on Tuesday. Put it just after your down pipe. Quote Link to comment Share on other sites More sharing options...
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