turbo bolt trouble

Guys, I've turboed my Miata and am having some serious trouble with keeping the manifold and turbo bolted together.

The BEGI kit came with 10 mm studs and bolts to hold it on. Strangest setup I've seen. The studs came with two bolts a piece. The way the directions suggested installing it was to put a bolt on each end to hold them together. I can't recall if the bolts were locking bolts or not.

It bolts together like this pic:

The stud goes between the two parts with a nut on each side to pinch it together. Same manifold design as well.

Either way they did great on the street and dropped out one by one at my latest track day at VIR.

I've decided I have two options to fix this:

~ Stage 8 bolts from FlyinMiata

~ Bolts that are drilled to use cotter pins and castle nuts.

I'm curious what you guys would suggest.

Also, has anyone had any luck drilling bolts for castle nuts on a bench with a vise and drill? I was thinking about how big a pain that would be and thought my best bet might be to go to a machine shop. I would need to indicate on the bolts where to drill the hole, I think.

Thanks for the help guys.

I'd be inclined to use a lock nut. Not a nylock - the nylon would melt, but a distorted lock nut.

If you don't like that, I'd go for the Stage 8. I know cotter pins suck. I don't know if the Stage 8 ones do, but it's hard to imagine them sucking as bad as cotter pins.

The Stage 8 stuff is pretty clever. You spin the nut on and tighten it. Then the teardrop bit goes over the nut and is held on with a C clip. Definitely easier to deal with than cotter pins.

Mechanical locking nuts are one option, and one that we used for years. The Stage 8 is a step up from that, as it can be used as many times as you want and there is NO way they're going to slip unless something bends.

Xceler8x, is the flange threaded, or are the studs simply being passed through a hole? If the latter, I'd go to a bolt instead of a stud with a nut on each end. Cuts your potential failure points in half.

I'd go drilled with safety wire since I also hate cotter pins. I have drilled bolts on a bench vice. It's not that hard, just start small and work your way up.

One way to drill the bolts is to use a nut as a guide. 1) Carefully drill a hole thru the hex nut, flat to flat. 2) Thread the drilled nut onto the bolt, and then use another nut to 'jam' the drilled nut in place. 3) Drill the hole thru the bolt using the guide holes in the drilled nut. 4) Disassemble, de-burr.

Carter

To keep the manifold on a 4 cylinder Esprit, Lotus used distorted thread (high temp) nuts, plus lock plates, which are 18 ga 304 stainless plates with ears that you bend over the tabs. They still come loose.

Anyway, lockplates and/or safety wire will be your best bet, I think.

I agree the lockplates would be the easist option. But I don't seem to get along well with C-clips although they work great. Always lose them into garage blackhole when I try to remove one, sometimes even installing one I lose it into the abyss. Oh well, sacrifice to the garage gods. As for cotter pins, I don't mind them so much (I'm aviation tech) but bolts are cheap enough to find already drilled. Although erohsic's directions are simple enough. My second option would be safety wire. Not that difficult to drill heads, there are even cheap templates/guides around that help for that.

Thanks for all the suggestions guys. I really, really appreciate the input. I'm about sick of my nuts falling off.

I'll follow at least one of these suggestions and let you guys know the results.

Icing on the cake...I read a post on miata.net from my turbo kit supplier. The thread is about V-band connections with turbos. Supposedly those things never come lose. The supplier's response? "All you have to do is ask and we can do it." F'tards. It's not advertised on their site and they knew my car would see serious track time.

Buy all your stuff from FM. I'm not just saying that because Keith is on here. Their parts always arrive on time, as described. They're always polite. I also get a call later from them asking if everything is ok. FM isn't cheap but it's worth it.

F'tards? Check the cost on the Tial V-band exhaust housings and then decide if its a typical offering.

I haven't had a single nut come off my setup in 5 track days so far. I don't get why so many people have issues. And I'm just using random nuts/bolts I cobbled together from my nut/bolt box.

Does anything besides the manifold hold the turbo on? If not, that's likely the source of your problem. Vibrations set up, bolts come loose. On 4cyl Esprits, the original exhaust manifold design has "issues." It hold up no only the turbo but half the rest of the exhaust as well. The last 2 nuts on the exhaust manifold, and sometimes the studs will just vanish on you, with your lockplates. My Dr.Hess BSH (build like a brick E36 M3house) manifold has 1/2" thick 304 plate running all the way back from the head to the turbo and I have no problems there.

splitime wrote: F'tards? Check the cost on the Tial V-band exhaust housings and then decide if its a typical offering. I haven't had a single nut come off my setup in 5 track days so far. I don't get why so many people have issues. And I'm just using random nuts/bolts I cobbled together from my nut/bolt box.

Yeah. F'tards.

I found this list of prices on google. The most I could find with a Vband and flange, no turbo attached, was around $200. I'd pay that to not have to deal with sourcing another way to make those bolts stay in place. The fact that it wasn't offered, but in a flippant way after my kit was purchased, burns me quite a bit. They have a fix for what seems like a widespread problem. Not advertising it even when they know it will be useful to me as a kit purchaser is being forgetful at best and deceitful at worst. This particular company also took over 3 mo's and 3 separate shipments to get me the purchased kit in the first place. I am not pleased with their service. By the way, this isn't slander as I kept my emails and bills of lading. I can back up my claims with proof of the shipping delays and missing parts in each shipment.

Interestingly enough I cranked on a random bolt when only one stud and bolt set had dropped out. It worked really well. Maybe the bolts you chose, not the ones supplied by the turbo kit manufacturer, were a better choice. Which is also interesting as this company has a sterling online reputation. I'm not toe'ing that line.

Hess, the kit has a rod support that connects at the start of the downpipe. During install I adjusted that thing so that it was taking a lot of weight. Maybe not enough, I'll try again.

Again, thanks for the help fellas.

Bolted joints are so easily done wrong. Here is the skinny from a mechanical engineer: Nylocks are excellent at keeping nuts from falling off, but they do very little against nuts loosening.

Lock washers suck at everything except cracking.

Loctite works great under certain temperature constraints assuming good primer.

Castle nuts are excellent as long as you aren't torquing the fastner, or relying on a specific torque. Don't count on it if you cannot tolerate small rotations (which you cannot in this application)

Safety wire is okay, but it needs to be done right, and there are tons of ways to do it wrong.

Locking nuts may work better, but I cannot imagine them working better than nylocks.

Those tab thingies from stage 8 may work, I have not tested any.

You would be surprised, however, because a good torqued bolt and nut works wonders. Those 10mm bolts are close to 3/8. With a grade 8 3/8 bolt, the dry torque should be 50 ft lbs for fine pitch and 45 for coarse. This is assuming no lube. I'll bet they weren't that tight. Try that first, with some good hardened steel washers. Go to tractor supply and buy some hardware - it's cheap there - because what they gave you will probably break of stretch too much at that torque.

Let us all know what ends up working.

-Brian

Xceler8x wrote: Yeah. F'tards. I found this list of prices on google. The most I could find with a Vband and flange, no turbo attached, was around $200. I'd pay that to not have to deal with sourcing another way to make those bolts stay in place. The fact that it wasn't offered, but in a flippant way after my kit was purchased, burns me quite a bit. They have a fix for what seems like a widespread problem. Not advertising it even when they know it will be useful to me as a kit purchaser is being forgetful at best and deceitful at worst. This particular company also took over 3 mo's and 3 separate shipments to get me the purchased kit in the first place. I am not pleased with their service. By the way, this isn't slander as I kept my emails and bills of lading. I can back up my claims with proof of the shipping delays and missing parts in each shipment. Interestingly enough I cranked on a random bolt when only one stud and bolt set had dropped out. It worked really well. Maybe the bolts you chose, not the ones supplied by the turbo kit manufacturer, were a better choice. Which is also interesting as this company has a sterling online reputation. I'm not toe'ing that line. Hess, the kit has a rod support that connects at the start of the downpipe. During install I adjusted that thing so that it was taking a lot of weight. Maybe not enough, I'll try again. Again, thanks for the help fellas.

You still aren't getting it. The full v-band conversion is not just the modification to the manifold. But the Tial V-band turbine housing... or the welding time/machining time to convert a normal turbine housing to V-band. How about the Tial one... here is the GT28 option... how about a "cheap" ebay one for sale... http://cgi.ebay.ca/Tial-Turbine-housing-V-band-GT28R-GT28R-GT28RS-.64-A%2fR_W0QQitemZ380115875210QQcmdZViewItem at 399.99. Another 50-100 dollars for V-band pieces to modify the manifold, then you need an extra flange/clamp to do the downpipe also. So figure ~5-700 in pieces for the upgrade... + the machining/welding time for the modified manifold and then a partially custom downpipe. Is it worth that price to you?

I don't know of any companies that just offer it in the miata world. You find it on the crazy high end kits in other markets though... it comes with that premium hard to hoist in our neck of the woods. Can the majority do it... sure, why not? If you are so annoyed though, why didn't you do your homework before and notice other Miata people talking about nuts/bolts having issues on their turbo cars. Then you could have addressed that with Begi ahead of time... or ask them to make something like that for you from the start.

Don't take out your lack of research and then them offering an alternate solution after the fact as their fault.

I can't speak to the timing/parts issues, but the V-band one I've done my homework on and run on my exhaust side for simplicity. You can't lay that one on them.

Once again... I am using random studs/nuts/bolts to hold my stuff on... 5 trackdays and its all still on. I just crank the crap outta mine.

BEGi is primarily a custom shop. If you want a V-band turbo setup and you're willing to pay for it, they'll weld something up. It might take a very long time and it might be expensive, but pretty much anything is an option. Sometimes they might not have thought of offering an option before you ask about it.

It's odd, though. Some turbo Miatas have constant problems with their fasteners. Others never have one come loose - of course, you never read about those on the forums My own turbo Miata is one example. I've never figured out exactly what determines it, although I suspect that studs that aren't quite perpendicular to the flange surface may be a factor.

tuna55 wrote: /long nerd thread

Completely agree. Run the car till hot and tighten them while warm and the problem goes away.

Been there, done that, got the t shirt.

Long nerd thread, hahaha.

I love it. That's what a couple of BS's will get you, I guess. I just love fasteners, they are wonderful if used correctly and they so rarely are. Funny, OEMs get fasteners very right, better than aircraft in my opinion, and it's amazing considering how many other things they get so wrong.

That being said, about lockwashers, when have you ever seen a lockwasher on a car in a stock application? Think about it...

-Brian

For my turbo manifold attach, I ended up using stainless drilled aircraft bolts, castle nuts and cotter pins. One can use safety wire instead of the cotter pins. If you are really crazy, you can safety wire the bolt heads too. Remember to buy some stainless washers to align up the castle nut properly. The cost of the hardware is not too bad. I bought the aircraft hardware from Aircraft Spruce & Specialty. http://www.aircraftspruce.com/catalog/hapages/an6.php

Those damn cotter pins were a pain - but no more lost nuts!

-Bruce

You can't really safety wire a bolted/nut combo. At the end of the day all that you end up doing is tying the nut to the bolt rotationally by running a wire through them, anchoring it does essentially nothing to aid in holding the torque. Drilling them in this manner, of course, does do a good job of locking them together, but only once. The second time it won't work unless you tighten until the holes line up, which is hacktastic.

I hate castle nuts in torque to yield apps, there is no reason. Can you find a single OEM example?

I should stop reading this thread.

-Brian

Umm, I think you are right - at least about reading the thread...

What is the big deal about "can you find a single OEM example"? Who cares? All I know is that the nuts haven't fallen off, nor have they loosened. I haven't safety wired the bolt heads because it doesn't matter for this application. I really don't care if the bolt rotates, if the nut is fixed in position relative to the bolt. (I agree that the anchoring does nothing to aid in holding the torque.) I can control the 'tightness' of the connection by stacking washers between the castle nut and the flange. The cotter pin prevents the nut from loosening. Reasonable quality steel in the bolt controls the amount of stretch and tightness. End of story... or am I missing something?

If so, I'd be interested in knowing more. Seriously.

-Bruce

splitime wrote: Is it worth that price to you?

For what I paid for the kit to work out the box? It might've been. I at least would've liked the option offered AS OPPOSED TO a flippant comment made after I purchased the flawed kit. They're my supplier. I am the customer. Is it too much to ask that they help to inform me of all my options? I've spoken with FM. They perform in this fashion.

If you are so annoyed though, why didn't you do your homework before and notice other Miata people talking about nuts/bolts having issues on their turbo cars. Then you could have addressed that with Begi ahead of time... or ask them to make something like that for you from the start.

Because I relied on them as the experts in this. I've performed research but I haven't been at this for however many years the supplier has been. Therefore I erroneously ass-sumed they would help me in making wise choices when purchasing their kit. I was wrong. Now, I'll also relate how the kit came late by 2 months. It also took them 3 shipments, over a month and a half, to get it right. I won't mention that they absolutely refused to expedite ship one part they forgot in the second shipment that was essential to the install. My car is on jackstands for almost 2 months because of an error in their shipping process. Then they refuse to expedite ship me a part that weighs less than a pound? Crap service all around.

Whenever I've ordered parts from FM they arrive on time and as ordered. Yesterday FM called me about some parts I ordered. They shipped them ground when I paid for 2 day shipping. This was due to a software upgrade that caused a glitch. They then offered to ship me the parts next day air at no further cost to me. That's customer service.

I gave the other supplier plenty of chances to do it right. I wasn't upset when the kit came over a month late. I was even reasonable about needing a second shipment to get things right when it finally arrived. When the kit required a third shipment and they balked at expedited shipping, my patience was exhausted.

Don't take out your lack of research and then them offering an alternate solution after the fact as their fault.

Actually. It is there fault for the reasons I've listed above. I won't toe the line of maintaining their online reputation for them by remaining silent. Try to shout me down as much as you want. It won't work.

As a supplier they are responsible for timely shipping, accurate shipping, supplying the parts I ordered, offering help with the kit itself, and honoring their warranty. As the manufacturer who supplied the kits they're also the subject matter experts. If they are aware of other options that may help to forestall future issues they should make am effort to inform the customer of those options. Then allow the customer to decide if I want to pursue that option or not.

This is the current model of customer service. Companies that don't follow this are going to get a bit of backlash as well as being labelled backward and hard to work with.

Once again... I am using random studs/nuts/bolts to hold my stuff on... 5 trackdays and its all still on. I just crank the crap outta mine.

Nice to know. Thanks for the suggestion.

Thanks for the further suggestions guys. I'm listening.

Tractor supply. I'll keep that in mind. I checked over my Speed3 to see how Mazda held that together. I swear it looks like they use the same bolts as they used on the Miata exhaust header. I may try to get some of those and a matching bolt. If the Stage 8 stuff isn't readily available I may try that as a Plan B.

Just found that my town has a Stage 8 supplier. I'll call those guys and see if they have stuff that will work in my application.

Thanks again guys. You're much more helpful than the adolescents at Miataturbo.net.

Here is my beef with castle nuts WARNING! LONG NERDY THREAD AHEAD!

So you torque the bolt and nut combo to a specific torque. What you are actually doing is stretching the bolt by a certain amount. Now, theoretically, as you said, you can shim the castle nut to something approximately close to the right height, and line up the cotter pin. First off, reality requires that the shims be discrete. You cannot add a .00003 shim I'll bet, so you're bound to be off of the theoretical correct height because of that when you torque it down. After that minor issue, you have this pin (or safety wire that doesn't anchor) that neatly slides through a hole you've created in both the nut and bolt. Well, the mere fact that you can slide it through means that it's somewhat sloppy. Unless you install a hardened pin with a hydraulic press, you can bet there's at least a few thousandths of clearance between the pin/wire and the hole. The gap doubles when it goes to one side of the bolt hole and the other side of the nut hole, so it can't really hold the correct torque, because it will always be able to rotate some nonzero amount under this condition.

This may not matter at all. Fine pitch threads will surely be more rotationally tolerant. Sometimes an academically perfect joint is not the only way to do it. Maybe if you overtorque the bolt (not really a good idea) and loosen it to the correct torque into the pinning device, you can get closer. I don't know. Maybe the bolt and nut will hold just as well at 50 ft lbs as 48 or 45 or whatever it really ends up being IF THE NUT MOVES.

That's the key. A good cotter pin isn't intended to hold torque, just hold the fastener together. So if it isn't a critical torque to yield app, it may be okay. if the engineer overdesigned the fastener (not terribly unlikely) the clamping force provided by a bolt torqued to 80% of its optimum may be sufficient.

It's all about clamping force. That's defined by the bolt diameter and the bolt stretch. Anything that compromises that is less than optimal.

Now, what you may have is a pretty cotter pin/wired joint that never gets used. If you torque the correct fastener to the correct torque, and just rely on the cotter pin/wire to hold things together if the torque ever does slip, then you might be fine.

So, Flexi, If your joints never loosened, you've never used your cotter pins. If the cotter pins were used, you would have to fight to get the pin out because the fastener would have backup up onto it. This is the most likely scenario. In that case, you're going overkill with making sure errant fasteners don't wreck stuff as they fall off, and that the turbo flange stays somewhat torqued on in the caste of a failure of the joint. This is a great idea, just don't expect it to actually hold sufficient torque.

/End nerdy thread.

-brian

For the fastenerds: on the right is a factory turbo nut and stud from a Mazdaspeed Protege. On the left is some aftermarket A2 stainless stuff. Who can comment on the differences?

Keith wrote: For the fastenerds: on the right is a factory turbo nut and stud from a Mazdaspeed Protege. On the left is some aftermarket A2 stainless stuff. Who can comment on the differences?

I'm not qualified to talk about it...so I'll give it a try.

The setup on the right has to work better than the one on the left. The one on the left is what didn't work for me at VIR.

Also, the nut on the right looks as if it's pinched into a triangle shape as opposed to the one on the left that's pinched internally into an oval shape. The one on the right also has a flat bottom that's splayed out a bit. I'm not sure what that means from a fastener standpoint but it would seem to give more area to clamp down on. Maybe that would help keep the bolt from loosening?

Someone who knows please speak up. I'm shooting in the dark here as I'm no engineer.

Tuna55 - thanks for the explanation on castle nuts. It was nerdy - but informative.

I'll concede the point that the nut probably has moved since I've installed it. And the cotter pin (which is not hardened) has taken the brunt of the nut rotation, which may a few degrees at most. So, it is likely that the force holding together the turbo to the manifold flange has been reduced. But, at least in my case, the bolts/nuts are still tight, the cotter pin is now preventing nut rotation (since the pin has been deformed) and the turbo/manifold connection is not leaking. I will continue to check the cotter pins to see if they are intact. It may be ugly when I have to pull the pins but I have no plans to do that since everything is still working. The freaking pins were ugly when I had to hammer them in to begin with... No room in there for a hammer...

For the OP, I wish I could help you on the stud question, but I'm an EE, not a ME. Of course I have an opinion but my observations are close enough to yours.

The actual turbo to manifold nuts on a 4 cyl Esprit really don't cause problems. The lock plates hold them down just fine. The bigger problem is in removing them, as it is so tight in there that for 3 of the 4 nuts (on studs) there's little to no room to work. Anyway, I think I would go lock plates or safety wire in the OP's case. Of course, dealing with lock plates is a PITA in and of itself.