Worst Case Scenario: Turbo damage and possibly engine too
09-10-07, 03:43 AM
#26
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Location: Varberg, Sweden
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You are not alone. I have had the same turbo failure. First the nut on the rebuilt secondary came loose and destroyed the compression fins. Small metal chips were found in the IC and the hoses.
After that, I cleaned all the hoses and replaced the IC and both turbos with rebuilt ones. 120km later the nut on the primary turbo came loose and a HUGE oil smoke screen from the tail pipe. I also found the little nut in the air intake box.
The primary is now replaced with a never touched turbo. The nut on the secondary that I now use was not that hard tightened, so I tightened it a bit more.
"I have heard that compressor surge can cause the nuts to back off as well, so you might check your BOV setup especially if it is aftermarket."
After I replaced a hose clamp between the y-pipe and the stock BOV I started to hear the BOV. I have not heard it before, so I guess that can be one of the reasons that my nuts came off.
Secondary:
Primary:
After that, I cleaned all the hoses and replaced the IC and both turbos with rebuilt ones. 120km later the nut on the primary turbo came loose and a HUGE oil smoke screen from the tail pipe. I also found the little nut in the air intake box.
The primary is now replaced with a never touched turbo. The nut on the secondary that I now use was not that hard tightened, so I tightened it a bit more.
"I have heard that compressor surge can cause the nuts to back off as well, so you might check your BOV setup especially if it is aftermarket."
After I replaced a hose clamp between the y-pipe and the stock BOV I started to hear the BOV. I have not heard it before, so I guess that can be one of the reasons that my nuts came off.
Secondary:
Primary:
Last edited by Macen; 09-10-07 at 04:06 AM.
09-10-07, 04:09 PM
#28
Just to comment on the thread lock, I've used it before in many RC nitro applications where engines get up to 30,000 rpms and more than 350 degrees F and the stuff still crystallizes at high temps and eventually breaks free. Usually, the bolts and nuts need to be replaced completely and it's considered routine maintenance because once it crystallizes theres no cleaning it. In fact, some people just put their engines in the oven at 500 degrees to get the stuff to break free, replace everything and put some new thread lock on.
I wouldn't hold your breath just with the thread lock, it probably can't hurt, but its not an end all be all for sure and eventually it will fail. Want proof, watch a RC plane or 1/8 scale gas car lose its flywheel in mid flight (plane is toast) or off a jump
I wouldn't hold your breath just with the thread lock, it probably can't hurt, but its not an end all be all for sure and eventually it will fail. Want proof, watch a RC plane or 1/8 scale gas car lose its flywheel in mid flight (plane is toast) or off a jump
09-10-07, 05:00 PM
#29
I would just keep an eye on it, maybe check the reverse thread nut every XXX miles and reapply with a new nut if you think its gotten weak.
Also, a good test to do is try using the same bolt and nut with the thread lock you want to use thats off the car, just on your workbench. Let the thread lock sit for a week and then test how much torque it takes to loosen/break it free. Now you have a gauge sorta speak and future tests would be to try and loosen the nut (the one on the turbo) and see how much torque you can apply without it breaking free. If it breaks free before you get to your measured torque, then you know how long it can last, assuming the test was done after XXX number of miles, under varying types of spirited driving, etc, etc.
Like I mentioned, most guys in the RC arena know how long their flywheels can go, (tanks of gas), before they "should" just replace the bolt and nut, as well as other items that use thread lock. It just doesn't last forever or as long as you would think.
Remember, the next time you lose a nut (no pun), it might be worse and find its way to your engine
Also, a good test to do is try using the same bolt and nut with the thread lock you want to use thats off the car, just on your workbench. Let the thread lock sit for a week and then test how much torque it takes to loosen/break it free. Now you have a gauge sorta speak and future tests would be to try and loosen the nut (the one on the turbo) and see how much torque you can apply without it breaking free. If it breaks free before you get to your measured torque, then you know how long it can last, assuming the test was done after XXX number of miles, under varying types of spirited driving, etc, etc.
Like I mentioned, most guys in the RC arena know how long their flywheels can go, (tanks of gas), before they "should" just replace the bolt and nut, as well as other items that use thread lock. It just doesn't last forever or as long as you would think.
Remember, the next time you lose a nut (no pun), it might be worse and find its way to your engine
09-10-07, 05:30 PM
#30
you don't read well do you?
1) mazda turbos DO NOT have reverse thread nuts/shafts.
2) with an intercooler between the engine and turbos, the nut cannot find its way into the engine because it is larger than the IC internal passages.
3) Even if the nut or smaller pieces of metal were smaller than the IC internal passages, they wouldn't get through because there would no longer be any boost to push them there...because the nut is gone, and the compressor won't be driven any more.
1) mazda turbos DO NOT have reverse thread nuts/shafts.
2) with an intercooler between the engine and turbos, the nut cannot find its way into the engine because it is larger than the IC internal passages.
3) Even if the nut or smaller pieces of metal were smaller than the IC internal passages, they wouldn't get through because there would no longer be any boost to push them there...because the nut is gone, and the compressor won't be driven any more.
09-10-07, 05:33 PM
#31
I would just keep an eye on it, maybe check the reverse thread nut every XXX miles and reapply with a new nut if you think its gotten weak.
Also, a good test to do is try using the same bolt and nut with the thread lock you want to use thats off the car, just on your workbench. Let the thread lock sit for a week and then test how much torque it takes to loosen/break it free. Now you have a gauge sorta speak and future tests would be to try and loosen the nut (the one on the turbo) and see how much torque you can apply without it breaking free. If it breaks free before you get to your measured torque, then you know how long it can last, assuming the test was done after XXX number of miles, under varying types of spirited driving, etc, etc.
Like I mentioned, most guys in the RC arena know how long their flywheels can go, (tanks of gas), before they "should" just replace the bolt and nut, as well as other items that use thread lock. It just doesn't last forever or as long as you would think.
Remember, the next time you lose a nut (no pun), it might be worse and find its way to your engine
Also, a good test to do is try using the same bolt and nut with the thread lock you want to use thats off the car, just on your workbench. Let the thread lock sit for a week and then test how much torque it takes to loosen/break it free. Now you have a gauge sorta speak and future tests would be to try and loosen the nut (the one on the turbo) and see how much torque you can apply without it breaking free. If it breaks free before you get to your measured torque, then you know how long it can last, assuming the test was done after XXX number of miles, under varying types of spirited driving, etc, etc.
Like I mentioned, most guys in the RC arena know how long their flywheels can go, (tanks of gas), before they "should" just replace the bolt and nut, as well as other items that use thread lock. It just doesn't last forever or as long as you would think.
Remember, the next time you lose a nut (no pun), it might be worse and find its way to your engine
As far as anything getting into the engine, there are louvers inside the intercooler bars that prevent even small particles from getting through. I looked in there with a mirror... but I get your point and appreciate the input.
09-11-07, 03:54 PM
#32
Check your avatar for what I'm doing right now, except I'm holding up BOTH hands.
Maybe they should
I get the point about pieces not getting to the engine, however, from reading this post from the beginning, and how "concerned" the OP was about his seals and what could have "failed with the turbo" ... I was under the impression, that this MIGHT be a possibility... and after I read 'alexdimen' post about the IC would probably blocking anything, but what about the IC itself, could that be damaged? I sure wouldn't want small metal filings in my IC, I bet thats hard as hell to get out? Over time, maybe they do work their way to the motor, maybe unheard of, but I bet until the nut came off the OP's turbo, he never thought that could happen either 
Maybe they should
2) with an intercooler between the engine and turbos, the nut cannot find its way into the engine because it is larger than the IC internal passages.
3) Even if the nut or smaller pieces of metal were smaller than the IC internal passages, they wouldn't get through because there would no longer be any boost to push them there...because the nut is gone, and the compressor won't be driven any more.
3) Even if the nut or smaller pieces of metal were smaller than the IC internal passages, they wouldn't get through because there would no longer be any boost to push them there...because the nut is gone, and the compressor won't be driven any more.
09-11-07, 05:04 PM
#35
I have one set of twins disassembled (cartridges/wheels still intact) that I've been keeping around for possible rebuild one day. The turbine blades are not all chewed up as they usually are, which is why I kept these. One compressor wheel has MINOR nicks on the blades (0.25-0.5mm) but it would not affect balance or use. I could sell them to you as is for around $100 plus shipping (the cartridges may still be good, you dont know until you try) or I could rebuild them first $500 including parts, plus shipping.
10-09-07, 02:29 PM
#37
I rebuilt the primary with a loctited nut, then put everything together with new crush washers and oil line gaskets.
I also marked the secondary wheels, then re-fastened the secondary nut with 266 high strength loctite. It was scary how easily the original nut came off!!!
I used type N loctite primer on the nuts because they are plated. Loctite recommends priming plated metals. It was worth the peace of mind.
BOV is fine.
The turbos and 90% of the intake is back in the car. I just need to put everything back in the front of the car, burp the coolant and it should be good as new. I'll know on saturday.
I'll get some pictures of the damaged parts this weekend for ***** and giggles.
I also marked the secondary wheels, then re-fastened the secondary nut with 266 high strength loctite. It was scary how easily the original nut came off!!!
I used type N loctite primer on the nuts because they are plated. Loctite recommends priming plated metals. It was worth the peace of mind.
BOV is fine.
The turbos and 90% of the intake is back in the car. I just need to put everything back in the front of the car, burp the coolant and it should be good as new. I'll know on saturday.
I'll get some pictures of the damaged parts this weekend for ***** and giggles.
10-14-07, 06:14 PM
#38
Everything is back to normal. Good vacuum, solid boost.
The only thing that is bothering me is that I can't hear my BOV when I disconnect it from the air box. Should I be able to hear it on a stock car like this?
I was doing this as a final test. I already tested the valve itself, then made sure it was connected to the charge relief solenoid via the intake manifold.
The only thing that is bothering me is that I can't hear my BOV when I disconnect it from the air box. Should I be able to hear it on a stock car like this?
I was doing this as a final test. I already tested the valve itself, then made sure it was connected to the charge relief solenoid via the intake manifold.
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