your thread repair techniques ??

steptoe · Post by **steptoe** » Mon Mar 12, 2007 10:31 pm

What are your preferred thread repair techniques and types when it comes to alloy components.

I have used the inserts that look like a spring Recoil ? brand that you use an oversize threaded hole to screw it into and the better hardened inserts that are more solid with pins on the outer edge that you knock down into place to finish off. These I like !!

I have just screwed the heads, cambox and rocker covers on the EA82T for Project Cheap Grief and bugger, even though I cleaned the threads, the camshaft seal carrier retaining bolts have crapped out threads - stopping me in my tracks

32ford · Post by **32ford** » Tue Mar 13, 2007 8:12 am

In Canberra I used Capital Thread Repairs. The guy came around At the time he said, fixed the problem (red motor water pump bolt with a broken easy out already in it), put in a helicoil and a stainlessbolt and charged me $70 to do the whole job. I don't know his number, but it was the best $70 I spent on the EH ever.

Oversteer · Post by **Oversteer** » Tue Mar 13, 2007 9:05 am

Do you mean the cam shaft cap at the front that holds the seal ?(can`t picture the head&cam system of a EA82....then again why would i want to ! )

Best method for thread repair in alloy if you have the tool is to weld it, drill and tap back to original size. A helicoil or recoil kit should work for you tho, on less important bits devcon, loctite thread repair, kneed it or quick steel expoxy work a treat in a bind.

OS

Marty · Post by **Marty** » Tue Mar 13, 2007 12:57 pm

My EA82 has a crossthreaded spark plug. I'll be getting it fixed one day soon but I'd prefer taking it to somebody who know's the biz.

YouTube · Post by **El_Freddo** » Tue Mar 13, 2007 1:50 pm

i've just done all my head bolt threads with the helicoil type replacement. I'm yet to get the heads on (gotta find all the bolts), reason for this move was that i've stripped out a few threads on other engines during tensioning and wanted these to hold well over time. I've seen a block that had a treated pulled out since the heads were put in last.

Oversteer · Post by **Oversteer** » Tue Mar 13, 2007 5:49 pm

Your ****ting me right !? Head bolts ! helicoiled into alloy block !

You used extra long coils right ? and loctite or somthing ?

If you don`t feel good about doing up head bolts or have stripped them on last attempt....buy a stud kit !

OS

steptoe · Post by **steptoe** » Tue Mar 13, 2007 11:26 pm

Yo Bennie , they where M11 loike the EA81 block ?

OS, I had an EA81 stud thread in block replaced with a stainless helicoil/recoil 180,000 clicks ago, you'd think it stronger than original alloy

Stud kit for EA82 ?

PS. Did 'em today, drilled out to 6.35mm using cam seal housing as a straightness guide, tapped 'em with right size tap then wound in the recoils in all four. piss easy

steptoe · Post by **steptoe** » Wed Mar 14, 2007 12:51 pm

splashed out !! on buying replacement inserts for my mate, I bought a repair set for the ever popular M6 1.0mm pitch and the M8 1.25mm. Ten thread coils in each pack and the tap and tool , drill bit not included. top up packs of ten M6 was about ten bucks, making repairs $5 bucks each for first ten then a dollar after that . shoulda done that years ago !!

YouTube · Post by **El_Freddo** » Wed Mar 14, 2007 1:06 pm

Oversteer wrote:Your ****ting me right !? Head bolts ! helicoiled into alloy block !

You used extra long coils right ? and loctite or somthing ?

If you don`t feel good about doing up head bolts or have stripped them on last attempt....buy a stud kit !

OS

No joke. I replaced a few threads on the now dead engine (seriously over heated twice), it worked well, only used the half inch (before inserted) thread. And lock tight isn't needed. If you've ever put one of these things in, they're not coming out anytime soon...

To me it will last longer than the alloy thread as the type of metal used in the re-threads seems tougher than the alloy thread. The alloy thread should hold better because it doesn't have the friction of a bolt thread screwing into it, rather it only receives the tension so there's very little movement in the thread itself.

Besides, my engine, if it dies in 6 months or so from thread failure, i'll let you know.

Cheers

Oversteer · Post by **Oversteer** » Wed Mar 14, 2007 2:58 pm

Doubt you`d have any issues on a motor that makes very little power so isn`t stressed, so good luck

(Yes I am taking the piss out of your supa powerfull engine ! lol)

Stronger than original thread.....not likely, its still holding into an alloy thread, and this time its not a thread cut at the factory with precision machinery, its drilled and tapped with a hand drill and hand tap.

I`m not taking the piss out of you, its just somthing I`d never want to see in my own engine/equipment on critical parts/areas because these days the labour to do such a thing is worth more than the engine/parts, and if it failed, well then it would be a small disaster finacially and time wise. Call it a past time or hobby or learning experience and then its all good, have fun

OS

steptoe · Post by **steptoe** » Thu Mar 15, 2007 11:05 am

to quote from the Recoil destruction sheet

" Recoil inserts are made from high strength stainless steel wire, wound to the shape of a spring thread. The insert is compressed during installation then allowed to spring back, permanently anchoring it in place. Because it is bigger, the insert has greater contact area and is normally stronger than the original thread"

gotta say I've never found a stripped helicoil/recoil thread!!

Subafury · Post by **Subafury** » Mon Dec 17, 2007 8:06 pm

to bring this up, i think i have a stripped captive thread where the oil/banjo bolt is on the bottom of my engine which goes to top of the turbo. ive just got new turbo on it but cant drive as its pissin out some oil. its currently at a zorst shop, will they be able to recoil it? or will maybejust some locktighthelp me out?

the bolt is fine and goes in but just wont tighten :'( i have no idea how it has stripped either.

Ben · Post by **Ben** » Tue Dec 18, 2007 9:29 am

You can helicoil anything so long as you have the clearance to go up to the next thread size (which there isn't always)

For anyone interested in the factory methods, and tapped methods there is two different female thread forming methods (well, more than two but two used in manufacturing)

The tap that you can buy at the hardware store cuts the thread from an undersized drilled hole (for a M6x1 hole you drill a 5mm hole). When a metal is cast or forged it contains a grain structure that creates the strength, when you cut metal it cuts into the grain.

Taps used in manufacturing don't cut the thread, they form it, buy forcing what looks like a bolt into the undersized hole (5mm for a M6x1 thread), when you look at the bolt though it has a vague triangular shape to it. By forcing the surface metal to conform to a shape, the grain is compressed but not cut.

A thread manufactured in this manner will be a lot stronger in all ways than a cut thread.

timmo · Post by **timmo** » Tue Dec 18, 2007 4:24 pm

you havnt lost the copper washer?

Subafury · Post by **Subafury** » Tue Dec 18, 2007 4:29 pm

got the problem sorted easily, thank god. used lots of good ol thread locker which did the trick. now i only have a very slow small drip of oil coming from it, which im happy with as i have bigger ones ahah

phillatdarwin · Post by **phillatdarwin** » Thu Jun 18, 2009 6:09 pm

u all have to remember when u used recoil kits it is the force of the bolt open up the spring thing u put in the tap hole that will make it stronger and u will find u will brake a bolt before u can pull the stud out

Mouse · Post by **Mouse** » Mon Jun 22, 2009 1:15 pm

Threadserts are another type of thread repair as well and are made buy Wurth these are similar to helicoils but are not like a spring but are like a grub screw with thread you cut a thread and screw them in then you screw another thread in which expands it in the hole which retains it . These can have some better benefits over helicoils when there is a lack of material to thread into such as sumps etc.
As far as alloy threads i wouldn't go past helicoils and i have had a lot of success with them in race engines and suspension components which have a lot of stress .