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jono

thread repair gurus, beyond coil inserts ?

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There are some other sort of thread replacement repair methods that a few pointers would be appreciated on.

 

I have thread rethreaders that clean up threads - almost religeously on any of the Subie alloy bits

 

Also got proper taps, just not plug taps :(

 

Also done coil - heli coil or recoil repairs

 

There is a further type I have never seen but heard about.

 

Sounds like a hardened insert that is mre than a coil and sounds like if dealing with M10 would need a sizeable drill and tap to thread these raved about but never seen inserts.

 

Anyone experience got a tutorial or link?

 

Be happy to hear and see, and some brand names etc

 

About to tackle some exhaust studs holes but wanna ensure I stick to the M10 1.25 rather than drill out and shove some imperial tap in .

 

Thanks all the same to those who suggest that route - not here in Oz

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Go to McMastercarr.com and mscdirect.com

 

Search thread repair.

 

Once you have a few names, you can also try ebay and amazon.

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Time Sert are the best I have used. They have held on a cylinder head on my old 240SX that was pushing 30lbs of boost. They cost a pretty penny, but it will cost more to buy an engine or many components do to a poor thread. Also of cleaning threads don't use a tap. Put slots in an old bolt and make a "chaser"

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About to tackle some exhaust studs holes but wanna ensure I stick to the M10 1.25 rather than drill out and shove some imperial tap in .

There won't be (m)any responses because this is like asking how to weld a soup can lid back onto the can before you put in the refrigerator. Subaru exhaust threads are such an easy, routine repair with a 100% success rate, few people spend time on elaborate options. Many of us repair those in 5 minutesand have no idea how many we've done with zero issues.

 

Describing the compelling reason to do a simple job differently might be warranted - whatever circumstance is causing the need for an exotic repair might change the preferred style/brand/model/approach.

 

1. google

 

2. stop into a couple of professional machine shops - after perusing google/Dave's suggestion above - and ask them what options you have, what options you've seen and opinions on the particular ones you like. focus on learning a new tooling or technique rather than just repair your current situation otherwise they'll be in "fix your heads" mode and won't understand why you're asking them to weld a soup can lid back onto the can.

 

if you have machine shops specializing in industrial, mining, etc locally like some areas do - try those as well even if they don't do automotive work. they may have good suggestions and first hand experience as they're seeing complicated high dollar repairs of machines and equipment. they might not want to talk if you can't/won't be an end customer and the clock is ticking at $120/hour.

 

3. a machine shop can also make repair inserts. i've had it done for subaru blocks and heads before. they fabricate a plug that threads into the block/head and has a receiving hole the same threads as the original bolt. i've never done it to exhaust studs. have to be sure you have the additional material available to remove to do this. if the hole is made bigger for a more complicated repair - then the internal clearances are being reduced, which may not be ideal. i've taken blown blocks and heads and drilled enormous holes to find the coolant/oil pages behind them and see how much material i've got to work with. not sure exhaust studs go up far enough to get close to cooling passages.

Edited by idosubaru
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Also you don't wanna use a tap for repairing existing threads. If you're just cleaning up existing threads you want a thread chaser. A tap will remove material whereas a thread chaser will just clean up existing threads. 

 

When I have bad thread issues, I've done all sorts of things to make repairs. If you can access both sides of the thing you're trying to thread my favorite is to drill the hole out really big and then make an insert with lip on one side, that way the nut/bolt can't pull the insert through the drilled out hole. But usually you don't have that type of access and its just a pain....

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Ripper thanks guys. Think it is timeserts I think I have seen before. I am a helicoil dude but have found the odd one when go back and remove stud or bolt some issues arise.

 

I am now thinking you 7/16 guys are on the money so if it stuffs up next step to drill out and helicoil back to M10

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OK. Found some local company selling timeserts on eBay and cannot repeat here what my mouth uttered when I saw the price of one size kit!!

 

Know I know!!

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You said non coil repair options, so I assumed you didn’t want timeserts. Timeserts are the same as helicoils, both work and both can be problematic depending on their use.

 

For a simple exhaust stud either should be fine but both are pricey. I’ve shipped my kits to friends before who then ship them back. Haha.

 

But yeah that’s why the 7/16” option is perfect. Easier, quicker, no drilling, success rate in exhaust studs is basically 100%.

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Weld the hole up and redrill and retap ive never done it in aluminum but i would guess you could aluminum braze the hole up then drill and tap but the part would likely need to be removed from the car but should be easy enuff and a solid repair the aluminum brazing is saposed to be as good as welding the joint if done right is stronger than the surounding aluminum and can be done with a map gas tourch

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OK. this page http://www.timesert.com/ pretty much informs my small brain in no time :)

 

It is more than a coil that could be stretched out like a spring - more like a bush insert as they call it.

 

Looks pretty neat

 

BUT I need to also take your experiences along and see if I can source a 7/16 stud, tap shouldn;t be to hard, likely have one if I look hard enough

 

No need to even drill out the holes in exhaust flange?

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the 7/16" thing is so money.  you're going to do it and think "wow why did i even bother researching and asking about anything else?". 

 

timeserts are better than helicoil though they're essentially the same thing in terms of concept and approach.  

 

helicoils work fine for most, if not just about all, subaru issues and they're used countless times for head studs.  

 

Start with timeserts if everything is equal to you and the 7/16" thing isn't appealing.  but if availability or some other compelling issue presents itself I wouldn't worry about it, the helicoils are working thousands of times over on Subarus. 

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Australia "officially" went metric in 1972 so I need to approach the suply joints gently and ask what studs they might have in 7/16" maybe just exhaust places equipped to deal with whatever.

 

Is there a vehicle you guys quote when buying 7/16 studs?

 

The number of times I have these things apart to tinker I am thinking of bicycle quick release axle set ups ! :D

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You know, when you think about what the guy hit me up for one visit to do an M11 1.5 helicoil repair to my block in 2000 - $90 the timeserts are cheap !!

 

Satisfaction of doing it oneself and getting it right is priceless.

 

Also noted somewhere the suggestion of thread locking goo for the helicoil going in, I would add copper grease to stud then going in 72 hours after thread locker has had its time to set nice. Something I have never done before.

Think only ever had two helicoils come out

Edited by jono

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I raced out to but shop and got UNF 7/16" grub screws in high tensile. Double ended studs only available in course.

 

The M10 1.25 of standard stud is about 20 threads per inch, so to UNF..

 

Found a pair if made in USA taps 7/16 20 in the workshop, plug and taper

 

I am all set!

 

Cost for four grub screws , four shiny nuts to match including 10% gst A$17

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Think I am gonna chamfer or countersink any hole to be tapped in future, helicoil or the like also

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Since the cylinder head exhaust bolts require a lot of tightening, you need a solid steel insert.  Heli-coils are wire inserts that do not engage the entire insert when the bolt is tightened.  Which is very very bad news.  The solid steel inserts are slightly too long, but use them anyways.  Do not try to drill a deeper hole in order to get the entire insert in the cylinder head.  Just drill to the depth of the previous hole, tap it, install solid steel insert, grind off the extra that protrudes above the cylinder head face.

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I've used helicoils on a number of exhaust stud repairs, idler bolt holes. Even a head bolt. I have yet to had one fail.

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Give these a go Jono:

 

013-2.jpg~original

 

Same as timeserts but are available in Australia and in different sizes, I grabbed this image for "display purposes" ;)  We've used them on a few things but I can't remember the specifics.  I believe they spread the load with the larger diametre insert.

 

Cheers

Bennie

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Way to go Bennie. Good work. I do miss Masters hardware mostly for their endless drawers of Champion products

 

I guess CTI-10 will be a good search reference if CTI-8 is for M10

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