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Michel31
Joined: 05 Jan 2021 Posts: 14 Location: France
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Posted: Fri Apr 23, 2021 2:53 pm Post subject: Torch experience on gearbox oil plug? |
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Hi All,
My 1978 Porsche 924 is giving me headaches. Since a few weeks now trying to get the oil drain plug out but it seems some red traces around it imply that red loctite was used by po.
I've got a bi Gaz torch that can reach 3300 °C
Has anyone tried to heat up such a plug with oil still behind?
Needs to go up to 260°C to melt the loctite but lower than 400 which is the flashpoint of the oil... although without oxygen, I guess it won't ignite right inside the 2.5l tank...?
Any piece of advice is welcome
Big thanks in advance
Michel |
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morghen

Joined: 21 Jan 2005 Posts: 9095 Location: Romania
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Posted: Fri Apr 23, 2021 3:40 pm Post subject: |
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if your torch can do 3000, it doesn't mean you should get your 924 to 3000
Do it in passes, hold the flame on for 5-10 seconds and then try undoing the plug. If it wont budge, do another 5-10 seconds of torching and so on.
I'm not sure about melting the loctite...i think its about getting the aluminium area around the threads to expand enough to dislodge the oxidized threads off the iron plug...so i would not heat up the plug but the area around it...carefully and bit by bit...then when the plug starts to turn...dont take it out completely...let the whole thing cool down with the oil inside..otherwise the hot surfaces will cook a thin layer of leftover old oil as their coating.
This is what i would do. _________________ Supercharger and EFI kits
https://www.the924.com |
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Cedric

Joined: 27 Aug 2004 Posts: 2808 Location: Sweden
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Posted: Fri Apr 23, 2021 6:39 pm Post subject: |
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Large impact guns solve alot of problems in my garage  _________________ 1980 924 Turbo
www.instagram.com/garagecedric/ |
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MikeJinCO
Joined: 08 Jun 2010 Posts: 1245 Location: Maysville, Colorado
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Posted: Fri Apr 23, 2021 9:35 pm Post subject: |
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Heat is a commonly used method for softening the red Locktite. But use the pass system it won't require a lot of heat. _________________ Mike
'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild) |
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Michel31
Joined: 05 Jan 2021 Posts: 14 Location: France
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Posted: Fri Apr 23, 2021 9:44 pm Post subject: |
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| MikeJinCO wrote: | | Heat is a commonly used method for softening the red Locktite. But use the pass system it won't require a lot of heat. |
Hi!
Thanks for the info...but what is the pass system?
I have just tried with my torch...very thin although very hot so no danger in fact of overheat ...well it did not move ...so will have to try longer... |
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Michel31
Joined: 05 Jan 2021 Posts: 14 Location: France
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Posted: Fri Apr 23, 2021 10:09 pm Post subject: |
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| morghen wrote: | if your torch can do 3000, it doesn't mean you should get your 924 to 3000
Do it in passes, hold the flame on for 5-10 seconds and then try undoing the plug. If it wont budge, do another 5-10 seconds of torching and so on.
I'm not sure about melting the loctite...i think its about getting the aluminium area around the threads to expand enough to dislodge the oxidized threads off the iron plug...so i would not heat up the plug but the area around it...carefully and bit by bit...then when the plug starts to turn...dont take it out completely...let the whole thing cool down with the oil inside..otherwise the hot surfaces will cook a thin layer of leftover old oil as their coating.
This is what i would do. |
Thanks for your reassuring description
So I applied this method, but my torch is very thin and it required a few minutes until it became can't touch it hot...even under tremendous torque like more than 150Nm as I was heating it did not move....so I will try longer harder...
Cheers |
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morghen

Joined: 21 Jan 2005 Posts: 9095 Location: Romania
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Posted: Fri Apr 23, 2021 10:58 pm Post subject: |
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wrap your tool  _________________ Supercharger and EFI kits
https://www.the924.com |
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Mike9311

Joined: 14 Dec 2004 Posts: 1798 Location: Chicago-ish
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Posted: Fri Apr 23, 2021 11:39 pm Post subject: |
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I agree with all of the above and just want to add
You can use a heat gun as well to preheat the transmission.
Also, use a piece of aluminum on the end of the plug and tap the aluminum with a steel hammer a few times. This can help to break up the loctite and the aluminum helps to not deform the plug. Cedric's suggestion for the impact wrench applies a similar effect. It isn't the spring like shock you give the plug with the hammer trick, more like a rattle, but it also works
I'm glad there is oil there since heated aluminum and steel typically leads to galling. Caveat, obviously, is the oil messes with the heating process _________________ 1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car |
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Michel31
Joined: 05 Jan 2021 Posts: 14 Location: France
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Posted: Sat Apr 24, 2021 12:40 am Post subject: |
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So...trial was not successful.
Tool on it at least 150Nm torque and optimized the flame so that it really got hot there... wow
And...nothing apart from denting the plug while it was heated...now a bit messed up and less grip...but still if it was only loctite would have worked...I need more torque...hence soldering.
Next chapter to come.... |
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procyon

Joined: 09 Sep 2015 Posts: 70 Location: Peers Alberta Canada
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Posted: Sat Apr 24, 2021 1:26 am Post subject: |
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Make sure that you can get the plug in the fill hole out before you drain the oil. No point in draining the oil if you can't fill it back up. _________________ 1981 924 N/A (Now the parts car)
1980 924 N/A ( 5 bolt discs and better paint) MS II V3.57
2003 Subaru Baja
2021 Maxda CX-30 |
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Rasta Monsta

Joined: 12 Jul 2006 Posts: 11733 Location: PacNW
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Posted: Sat Apr 24, 2021 1:58 am Post subject: |
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| procyon wrote: | | Make sure that you can get the plug in the fill hole out before you drain the oil. No point in draining the oil if you can't fill it back up. |
+1000 _________________ Toofah King Bad
- WeiBe (1987 924S 2.5t) - 931 S3
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Mike9311

Joined: 14 Dec 2004 Posts: 1798 Location: Chicago-ish
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Posted: Sat Apr 24, 2021 2:34 am Post subject: |
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This is exactly the kind of thing I wish I was there, on the ground in France, to help
Need a teleporter _________________ 1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car |
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Michel31
Joined: 05 Jan 2021 Posts: 14 Location: France
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Posted: Sat Apr 24, 2021 3:08 am Post subject: |
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Filling plug was also a pain and ended up in a 12mm thread counterclockwise to try opening it with a hexagonal 18mm bolt...no way! Even with a crank jack and the car on its tip toes...!! So I gave up, it will be filling through the hole and plug with a copper seal.
While experimenting on this filling plug, I tried with a monster 10mm screwdriver and guess what a tiny bit broke off into the gear box!!!
Reason why I need to have a large drain hole to get rid of this bit with a magnet...get a boroscope camera in...do some cleaning up.
The car is running great otherwise...really stupid that I tried this gearbox drain .. pffffff
Last edited by Michel31 on Sat Apr 24, 2021 6:40 pm; edited 1 time in total |
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Michel31
Joined: 05 Jan 2021 Posts: 14 Location: France
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Posted: Sat Apr 24, 2021 3:51 am Post subject: |
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| Mike9311 wrote: | This is exactly the kind of thing I wish I was there, on the ground in France, to help
Need a teleporter |
Thanks for the thought
You'd be most welcome |
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Michel31
Joined: 05 Jan 2021 Posts: 14 Location: France
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Posted: Sun Apr 25, 2021 5:15 am Post subject: |
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| C�dric wrote: | Large impact guns solve alot of problems in my garage  |
Hi Cedric
Thanks for the info
Which torque would you recommend for the impact gun? An elec one at 600Nm would be enough?
Cheers
Michel |
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