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Exhaust studs


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Got an '86 Brat.  Y pipe rotted out. found a firm that remanued them, brought it to my local long time muffler shop.  when done presents me with bill after I pay he says "there's still one little problem, the studs are stripped and we can't tighten the exhaust pipes to the header!  A muffler shop that can't deal with stripped or broken studs?  Anyway wound up going to a custom shop who says he can fix but wants me to get original equipment studs.  My local Subaru stores' parts computer does not go back tha far in time.  Is there anyone out there who knows or is aware of where I can get the OEM specs for those studs?   Sorry for longwinded story but I need help.

Denem

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Well, unfortunately, that's typical of many dealerships these days.   :angry:

Just like a couple years ago when I went to a dealer to pickup a thermostat for my 83. The kid behind the counter said he couldn't even look one up, because his information didn't go back that far...

And I'm thinking to myself, I can look up a part number on my phone, and they probably have one, but the whole scenario just disgusted me so much, I went to Napa. 

 

The studs are the same for most any year Subaru. There may be some slight length differences, but every one I've ever seen is 10 x 1.25. But I haven't worked on anything super new. They are stainless though, as well as the nuts. So keep that in mind if you source them from somewhere besides the dealer. 

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I have never seen a stainless 10 x 1.25.  I've had cars with OEM parts.   I've looked.   The nuts, yes, I have those in stainless.  I have found 10mm stainless threaded rod, but never the 1.25 pitch.  If anyone ever finds stainless 10 x 1.25, let me know.

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Does the ea81 still have the exhaust recirculation spacers? If it does I would ditch those. The studs that go directly into the head without the spacers are the same as any ej engine. You can go in to the dealer and ask for exhaust studs for a 2017 sti, 00 forester, 93 Impreza, etc. it doesn't matter it's all the same. If your dealer sucks there's this http://m.ebay.com/itm/Subaru-Exhaust-Y-Pipe-Upper-Stud-Nut-Kit-WRX-Impreza-All-EJ-FB-Motors-90-17-/201657272156?fits=Make%3ASubaru&epid=1484195666&hash=item2ef3b5c75c%3Ag%3AFKIAAOSwGtRXxjCE&_trkparms=pageci%253Ad669834e-58a0-11e7-8e43-74dbd18052af%257Cparentrq%253Ad8a58d5215c0aa18b13c12ecfffe716e%257Ciid%253A4

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You can install heli-coil's directly into the spacers above the header flange. It's already the right size to run the 10x1.25 STI (screw thread insert) tap into it. Then you install a heli-coil but don't break off the tab at the bottom. Use exhaust studs for a Legacy from the dealer and let them hit the tail on the heli-coil as a depth stop. Then just bolt up the header as normal. Been doing this for about 20 years now....

 

You can also remove the spacers as noted but if you do this you will have to either rotate the flanges on the header, or you will still need to do the thread repair. Also the header may not fit as well since technically the headers that didn't use AIS spacers were taller to account for there not being a spacer. It will probably work but the exhaust may hit the subframe and will be closer to the rack bellows, etc. Personally I like leaving the spacers because they are steel and once you install heli-coil's into them the threads are strong and you won't have this problem again. Which is a result of the studs being directly installed into aluminium heads. 

 

GD

Edited by GeneralDisorder
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Skip the helicoil and get 7/16 exhaust studs and a tap.

 

You can get that size stud at most auto parts stores.  

 

The ones I like to use are corse thread on the head side, and fine thread on the end that holds the pipe.

 

This way you can tap the head directly, without having to drill out more material and chancing the helicoil coming out further down the road.

 

And it leaves enough meat so that if they strip again, you can still then go to a M10 helicoil or threadsert.

 

****bonus**** the standard studs are cheaper than metric and easier to find in longer sizes.

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Personally I hate having SAE fasteners mixed in with metric on an Asian vehicle. I get enough of that on my Trans Am with Australian differential, metric body, and SAE engine/trans.

 

GD

 

I hear ya.  And for most things I agree.  

 

The exhaust stud issue for these cars is my exception.

 

I do like your idea of helicoil in the steel spacers.  Also a good fix, but doesn't apply to EA82 or Deleted ASV spacer EA81s.  Or any EJ's.  I had to repair 4 studs on a EJ25d just last week.

 

I have just had too many bad experiences with helicoils coming out the next time the exhaust is removed.  Threadserts are better.  But more expensive.

 

Customers don't like to pay my price of $35 a piece for the cost/time/trouble of installing an insert of any kind.  By using the 7/16th, it's quick, you leave room for future repair, and I can charge $10 for the same fix.  When you have 4 studs on the same engine to fix, the difference between $40 and $140 is signifigant to the customer.

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I get all my insert supplies (including for head bolts, etc) from Chrislynn:

 

http://chrislynninserts.com

 

It is necessary to use red loctite on the OD of the insert. I haven't ever had one come back out. We do A LOT of 10x1.25's anyway because if there's even a question on a timing belt component we just do them all. 90 degree air drill and mechanics length bits makes short work of it.

 

I also don't stock anything SAE. All our hardware us supplied by Wurth and it's all JIS.

 

I used to advocate the 7/16 route also and that may work out better for the DIY I suppose. Depends on what you have access to - if the only thing around is a NAPA that carries spare corn-binder bolts and Saskatchewan socket sets then you'll just have to make do....

 

GD

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The shop might think you mean just installing new studs but thats not even what you need, you need the bolts threads repaired. Maybe you need new studs first but that's easy, the first shop would have probably done that.

 

You should clarify that.

 

Actually the studs are probably reusable, though they'll function as bolts with the nuts seized in place. LOL. Purist will frown but I reuse them without issue.

 

I hear ya. And for most things I agree.

 

The exhaust stud issue for these cars is my exception.

+1 same here. I do both and have both on hand but the 7/16 trick I got from you guys years ago is a sweet deal and my current go to for this. I hate having SAE too but I'll deal with it for this.

 

For you two guys - If he has to have a relatively unknown shop do this which solution is the best to hand off to them?

 

Maybe you could just take the SAE stuff - taps and parts and ask any shop to do it. With that and printing out this thread a shop would have to be imbeciles to not be able to pull it off.

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First you need to interview the techs and find one that can run a tap in straight. Check his eyesight and give him a field sobriety test maybe.

 

Also give them a knowledge test on metric to SAE conversion - if they know the 25.4 conversion factor and their eyes are symmetrical, and they can walk a straight line.... yeah maybe.

 

People working on cars at random shops.... It's bad out there. I get all the screw ups from all over the metro area. Ridiculous....

 

GD

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First you need to interview the techs and find one that can run a tap in straight. Check his eyesight and give him a field sobriety test maybe.

 

Also give them a knowledge test on metric to SAE conversion - if they know the 25.4 conversion factor and their eyes are symmetrical, and they can walk a straight line.... yeah maybe.

 

People working on cars at random shops.... It's bad out there. I get all the screw ups from all over the metro area. Ridiculous....

 

GD

 

Both my local Machinist are Strabysumatic (cross-eyed)

 

I think it actually helps them line stuff up like when you close one eye to look through the sights of a gun.  HAHA

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DO NOT USE HELICOILS.  They strip out easily and then you are screwed.  Use a solid drilled in metric insert that fits exactly the original stud.  You can pick up the studs off of a junk car by tightening together 2 nuts over the end of the stud, and unscrewing the old stud.  You do not need to use stainless steel.

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I've used both, Heli-coils and the solid, "Thread-serts" type. Both work well when installed correctly. Many people have had a bad experience with Heli-coils because the hole was too far gone or they didn't tap it properly. But, if that happens, you still have the option of going with a larger diameter Thread-sert. If you skip the Heli-coil, and screw up the Thread-sert, then you are truly screwed!

 

But I'm not sure why you would recommend buying the higher priced Thread-sert, and then advise getting used studs from a junkyard? They aren't that much at the dealer, and they aren't corroded at all. Yes, you do need stainless. Factory studs are 304 stainless. Try installing non-stainless, and get your Heli-coils ready.  :huh:

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I my opinion it's a good idea to give the rest of the exhaust system a quick look while your at it. If the pipe/muffler hangers are missing or in bad shape this helps to rip the studs out of the heads, even if you just repaired them.

Edited by Crazyeights
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