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The threads stripped on the CHRA's oil feed - What does one do?

The threads stripped on the CHRA's oil feed - What does one do?

 
Old 11-19-2018, 10:22 AM
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Default The threads stripped on the CHRA's oil feed - What does one do?

Whats up guys, i know i already have a build thread but this is an unusual problem and felt it deserved it own thread. Long story short, i bought the STC Hunter that boosted94gsr was using on his coupe. I was waiting to upgrade until i got my new short block together, but my turbonetics super 60 started smoking so i figured why not go ahead and upgrade to the ball bearing life lol. Well, i dont have a welder at the moment, so i took the car to a reputable local Honda shop to have a 4 bolt flange installed. Well... after i picked the car up, i noticed the oil feed/restrictor was leaking where it threads into the chra. I take the oil line off and restrictor and see that they stripped the threads on the chra Theyre closed today and im going up there tomorrow to talk with them and see if we can sort things out. In the meantime im looking for solutions. I really dont want to drill/tap a chra or helicoil it because of how shallow the female threads are (maybe 1/3" at most.) Someone suggested getting a 2 bolt flange style adapter, which sounds great but then we noticed the oil port is significantly off center which would create oil flow issues. What do you guys think?
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Old 11-19-2018, 11:54 AM
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Default re: The threads stripped on the CHRA's oil feed - What does one do?

Just get a 2 bolt oil feed flange. You oil inlet looks like a 1/8"npt, just get a flange that has a 1/4"npt inlet if your worried about it being off center. So you will need a 2 bolt flange with 1/4"npt inlet, and a 1/4"npt to -3 adapter. We carry these in stock just let me know.
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Old 11-19-2018, 12:58 PM
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Default re: The threads stripped on the CHRA's oil feed - What does one do?

Attention Shodan ... come in Shodan !!!
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Old 11-20-2018, 08:17 AM
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Default re: The threads stripped on the CHRA's oil feed - What does one do?

Originally Posted by sneakypete View Post
Just get a 2 bolt oil feed flange. You oil inlet looks like a 1/8"npt, just get a flange that has a 1/4"npt inlet if your worried about it being off center. So you will need a 2 bolt flange with 1/4"npt inlet, and a 1/4"npt to -3 adapter. We carry these in stock just let me know.
I know Sneakypete quite well, and honor many of his opinions, but in this case, NO! This is an extremely bad idea. There are several things to note.

1) using a 2 bolt flange will make things quite worse. I have a write up on oil restrictors and their type to use, and there is a reason why so many turbochargers, (mainly the journal bearings, but ball-bearing versions suffer also) die while using these two bolt flange oil feeds. Details about this flange restrictor are found here

2) This entire oil inlet now is contaminated thanks to the babbit now found in the inlet in the photo provided, and must be flushed out with oil. Now, I don't know who did that, yourself, or the shop, with this attempt to helicoil or repair the threads, but you've essentially contaminated the oil inlet. compressed air must be applied to the side of the oil inlet (to keep the babbit from actually entering the CHRA, which it looks like some has already), and The turbocharger must now be carefully removed from the car, and flushed out with oil, (pressurized oil if possible, and NOT from the engine). This babbit can cause serious damage to the shaft and bearing system inside the CHRA.

So what happened, you ask?
What I believed happened here is your reputable shop, didn't carefully put your oil restrictor back in by hand, starting off the 1st few threads, then used a 15mm socket and cranked this oil restrictor down, stripping the threads. The restrictor itself is now useless, but the threads in the CHRA are a steel alloy, which means that you can still carefully clean out the inlet, flushing it with a lot of oil and air, turbo needs to be off of the car.

So what can I do, and what SHOULDN'T be done?

Fact 1: You cannot use helicoil on this, don't bother, you'll just kill the turbocharger faster from the babbit from the helicoil which is even more rigid than the metal babbit from the cross threading.

Fact 2: Don't try to use a 2 bolt flange system, you'll just have inconsistent oil flow. If you must, sure, but you have at least one more option when it comes to that. If this were a Journal bearing version, I'd say you'll definitely screw the turbo up for certain. With a ball-bearing CHRA using a 2 bolt female flange, you're about maybe 45%-60% likely to kill it. It just won't be immediate. It'll take a few months. GET A NEW 7/16-24 RESTRICTOR

Fact 3: Your best bet is to

A) cover the inlet hole with a finger and then blow out the existing babbit with compressed air until ALL the material has been removed.

B) remove the turbo completely, and flush out the the entire CHRA with petroleum-based parts cleaner (automotive parts washer solvent if you can). That's the best solution, but you can also create a parts cleaner from using these ingredients into a small disposable squeeze bottle, and jet the solution into the CHRA
-1 quart of ATF fluid
-1 litre of Kerosene
-1 litre of Acetone

These components are used in many gun cleaning solvents, (FYI). You'll easily use an entire 4-6 oz bottle throughout this process.

Cycle the solution through by rotating the shaft (by hand slowly) while pouring the oil through the CHRA, .Let the oil drain onto the sink or surface of where you're setting the turbocharger.

C) Thoroughly clean the CHRA oil inlet first before thinking of using a tap - The reason why helicoil and using aluminum restrictors doesn't work well is because the CHRA is made of an Iron-Nickel alloy, and is basically a steel thread, that shouldn't be retapped. Those threads are much stronger than you think, so before going to this extreme, get a NEW threaded restrictor first, and try to carefully rethread this by hand. You'd be surprised how your first cleaning got rid of a lot of babbit and other debris from the fine threads of the oil inlet, and you may have solved your problem. But don't retap unless the new restrictor fails.

D) Retap the existing threads ONLY IF NEEDED, do not attempt to "drill & tap" -WORSE CASE SCENARIO - You'll need to buy a specific tap for this, as it does NOT use a 1/8thNPT or 1/4NPT system. These use the same 7/16-24 thread pitch as the GT series Garrett Ball-bearing series turbochargers. (They also use the same 14mm x 1.5 water fittings as the Garrett GT, while the Journal Bearing water fittings are 3/8thNPT). You can find a steel 7/16-24 tap
Here in this link Here in this link

Once the Oil inlet is cleaned out as in step C, AND ONLY IF A NEW RESTRICTOR CANNOT BE SCREWED IN BY HAND, do you resort to re-tapping the threads. Put the tap in by hand first for the 1st 3-4 threads, and then use a chuck to slowly walk the threads down, again, by hand. you will not likely need to hit bottom to be done.
Once you've done that, apply step C again, thoroughly cleaning and flushing out the oil entry. Finally, pump in about 3oz of regular oil into the oil inlet, again, (rotating the shaft while doing so) and let it sit for a day. The following day, check for any metal flakes or babbit within the oil that's drained out.

That's the best you can do. And yes, you'll need to pay for a few materials and parts. But they aren't expensive, and it's not the end of the world. From now on, no more turbos for the "reputable shop".. k?

Please read this thoroughly.. I hope this was helpful.

Last edited by TheShodan; 11-20-2018 at 01:50 PM.
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Old 11-20-2018, 11:43 AM
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Default re: The threads stripped on the CHRA's oil feed - What does one do?

^deserves a reward of some sort
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Old 11-20-2018, 01:36 PM
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Default Re: threads stripped on CHRA oil feed

Originally Posted by Autoworks View Post
^deserves a reward of some sort

Shodan, thank you


Greg, I agree, tough to find people willing to go to lengths to help those in need. I guess ill be buying another restrictor from you (Im the guy that bought the hoodie/restrictor last week)

Edit: Sneakypete, thank you as well sir. if a new restrictor doesnt work, ill buy those fittings from you.
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Old 11-21-2018, 02:49 AM
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Default Re: The threads stripped on the CHRA's oil feed - What does one do?

Just for my own knowledge - is it typical to have the hole that far off-center on the flange, or is this just a one-off with a poor alignment?
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Old 11-21-2018, 05:11 AM
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Default Re: The threads stripped on the CHRA's oil feed - What does one do?

Originally Posted by DaX View Post
Just for my own knowledge - is it typical to have the hole that far off-center on the flange, or is this just a one-off with a poor alignment?
It's a cast piece like all CHRAs. All of these companies have an off-center occassionally. Been like that for decades. Most just don't notice.
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Old 11-21-2018, 05:33 AM
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Default Re: threads stripped on CHRA oil feed

Originally Posted by k20z1ej1 View Post
Shodan, thank you


Greg, I agree, tough to find people willing to go to lengths to help those in need. I guess ill be buying another restrictor from you (Im the guy that bought the hoodie/restrictor last week)
Oh really, thanks...I'll send you a new restrictor w/ the hoodie. Thanks
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Old 11-22-2018, 03:30 PM
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Default Re: threads stripped on CHRA oil feed

Originally Posted by Autoworks View Post
Oh really, thanks...I'll send you a new restrictor w/ the hoodie. Thanks
Thanks man, you're good people
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Old 11-23-2018, 10:20 AM
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Default Re: The threads stripped on the CHRA's oil feed - What does one do?

use this
Amazon Amazon


weld it shut and drill it to the what size you want, clean the chra where its damaged.. turn upside down and fill drain with oil and let it seep out the inlet to push anything backwards. Done this a on a car once, worked well for as long as it was on there.
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Old 11-23-2018, 02:03 PM
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Default Re: The threads stripped on the CHRA's oil feed - What does one do?

Again, this is the type of restrictor we're precisely trying to avoid for a situation like this.
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