18 replies to this topic

[mini-auto]

Sump plug threads stripped in the sump of my Blue auto.   Mentioned it to a chum who used to ride pre-65 trials & he recommended these. http://www.chronos.l...EPAIR_KITS.html

 

£32.28 delivered !   Not a bad price, I have ordered a set.

 

5/8 " UNC THREAD REPAIR KIT  (Ref: HEL5811)
 

HELICOIL TYPE THREAD REPAIR KIT 5/8 x 11 UNC
to Repair Female threads in Steel, Cast Iron and Aluminium.

INCLUDES 10 HELICOIL TYPE INSERTS, PLUS...
INSERTION TOOL
TANG BREAK OFF TOOL
HSS TAP
INSTRUCTIONS
YOU MAY REQUIRE A SUITABLE DRILLBIT(NOT INC) - 16.25 MM

CLICK THE IMAGE FOR A LARGER PICTURE

£26.90 £32.28

 

[govig]

Hi auto, I think helicoils are only OK for a thread repair where you are not continually removing the fastener and it's not safety critical. You would be a lot better off putting a Würth Time-Sert in or even tapping a bigger metric coarse thread if there's enough thick metal around the drain.

 

Time-Serts aren't cheap but non branded helicoils are a bad joke in comparison (edit imo).

Edited by govig, 05 July 2015 - 12:50 PM.

[Craig89]

Theres nothing wrong with helicoils, perfectly acceptable solution to your problem

[govig]

Just to clarify, Helicoil is a trade name (rather than a type) of good quality thread repairs and the insert has considerably higher strength than the original thread tapped in the alloy. They are used in the aero industry I used to work in and have a very good track record if inserted correctly. However in applications where the fastener is continually being removed and replaced, like an oil drain, I think there is a better choice. It all depends how often you change your oil and how much use your Mini gets. If it's not much and the insert has say 20+ use cycles it may well out last your interest in the car by a big margin.

 

We had continual trouble with 911 brake caliper bolt threads which are tapped into the alloy hub. The long M12, I think, bolts had to removed every service and when the pads needed renewing. Helicoils would last a few years and if/when they fail it can be a miserable experience getting the bolt and the insert out. Since switching to Time-Serts ages ago there have been no futher issues.

 

The hardest bit in repairing a drain bolt thread is stopping swarf getting into the sump. Imo I don't think you can stop it all which suddenly makes it a big job if you want to be really sure. Some people are unsurprisingly tempted by those tapered drain plugs but they can split the sump in certain situations.

[spiguy]

Fair points above, as they are based on experience, however I work in environmental testing and we use aluminium fixtures to attach product to and then that is attached to a vibration / shock table where we perform long duration environmental testing such as flight vibration, transport vibration and shock etc. We use helicoil type inserts in all of these, and they see hundreds of torque / remove cycles with very low failure rate. In fact I can only remember ever seeing one 'fail' which was actually due to the re-use of a worn cap screw rather than an issue with the insert itself.

 

Just offering another view based on my experience of them.

[govig]

Fair enough spiguy. You're findings are based on experience too.

 

One thing neither of has mentioned is the depth of the thread. I think if it's deeper especially on small od screws, the better a Helicoil will function. Mini drain plugs are fairly shallow (when the plug od is taken into account). When you buy a Time-Sert solid insert, you choose the depth for the exact requirements you need. I think the Time-Sert insertion tool and method ensures is cannot be fitted to far or in any way incorrectly and there's nothing that needs breaking off. There are other makes based on the same principle with similar sounding names.  

 

Edit: no connection with Würth other than as a retail customer : )

Edited by govig, 05 July 2015 - 05:21 PM.

[Spider]

A Helicoil can do the job and get you out of gaol, I've found many of them fitted over the years for the Sump Pug (it's a BIG bolt, so it MUST be done up tight - yeah?    ).

 

If fitting one, you do want to be sure that it is square, otherwise, it will leak. I forget how far off they can be but it ain't much. I've also found, as govig has pointed out, that after a while, they start 'gripping' the sump plug. Also, be sure that the 'top' of it when fitted goes done below the surface otherwise it won't ever seal. I mention this, because it's surprising how many I've found that haven't been - or they are starting to come out (re: previous comment).

 

Time-serts are the bee's knee's for this application, but I find it hard to stomach how much they are to buy!

 

So, I make my own version from an M20 Bolt;-

 

 

and fitted;-

 

 

What I have found since fitting these is I no longer have to wind the plug ALL the way out, then wind them ALL the way in again, just 'crack' then and wind away with the fingers.

 

Just a note on the sealing washers. I know the stock ones are cooper, however, these do work harden after a few cycles and so 'need' nipping ever tighter each time, so annealing them from time to time isn't a bad idea, though the Fibre type washers are better, but need replacing each time.

[govig]

Do you sell that conversion spider? 

 

Time-Serts are expensive I agree and it is annoying, just like Snap-On, that there are not that expensive in the US. Customs and post adds a significant amount to get them here. I assume you have they same issues getting them sent to Oz. 

 

Regarding annealing copper washers, I'd do this every time. It takes a less than a minute although some are using Dowty washers with good results.

[spiguy]

Very ingenious Spider!

[Spider]

Do you sell that conversion spider? 

 

Time-Serts are expensive I agree and it is annoying, just like Snap-On, that there are not that expensive in the US. Customs and post adds a significant amount to get them here. I assume you have they same issues getting them sent to Oz. 

 

Regarding annealing copper washers, I'd do this every time. It takes a less than a minute although some are using Dowty washers with good results.

 

 

Sell them?  Now that's an idea !!!   The dozen or so I have done, I've had plated and given away !!!

 

Yes, I too have found in recent years that the cost of postage / freight both from the UK and the US is outrageous, however at this time, if we keep the value down below (I think) $500 AUD, we don't have to pay duty or customs, but that's soon to change.

 

 

Very ingenious Spider!

 

Cheers

 

Buy that man a beer!

[mini-auto]

Job for tomorrow afternoon,  5/8-UNC tap, M20 bolt, +lathe.

 

[mini-auto]

M20 outside, 5/8-UNC inside, left it a bit on the long side I can always shorten it if needed.

 

 

 

 

Tap the sump, install with thread lock, job done.

[Craig89]

Nice job mate! Good solution

[Spider]

Nice one!  You were a little quick for me though (sorry - 40 lashings to me), I would have suggested running the parting tool just under the head of the bolt to remove that taper they all end up with where the thread ends, but hey, just put a decent chamfer in to the M20 thread in the gearbox.  If you can afford a couple of more days, send the adaptor out for plating so it doesn't rust.

[mini-auto]

Thank you.

 

Good tip too, I'll get it back on the lathe tomorrow & undercut the thread under the head, no worries.