Ferrari 308 GTS - Gearbox fill plug

Sounds like you've got it properly sorted, but Ferrari has a history of under-designing the thread engagement length of the male steel drain plug threads going directly into (soft) Aluminum female threads. I'd guess that they were trying to minimize the weight of things, but it has proven to be a bad choice for good serviceability (although some of the blame can probably be placed on over-tightening).

 

No, you don't have to get fussy about it. That's a zero pressure reservoir, and that gearbox fill plug is not even significantly wetted when the car is not in motion. If you under-torque it too much, and it weeps a little, you can always just nip it up a little tighter.

They had so much of this problem on the gearbox drain plug and engine oil drain plug on your model that they eventually added a steel helicoil to the female threads (circa 1978 IIRC) so they would be more resistant to getting stripped out (but even the helicoil can get mangled).

 

When you drain the box again you can place a timesert in there if you don't have enough threads or want to fix the threads. Helicoil" is a word you probably heard before but timesert" is better.

 

Timeserts are far from better. Butchery is a better word.

I have helicoiled many but in that particular application I would continue to do what you are doing. The casting has a great many threads and it will continue to work well.
In that location with the engine in the car a thread repair of any kind is tricky and can go wrong. The longer plug is a very good, permanent fix.

 

No butchery is the guy who F'ed it up in the first place.

 

Tight enough to not leak? Seriously, I don't think Ferrari ever gave an official spec (and, for many places where an annealed copper sealing washer is used, it's not really possible to put a torque wrench on it). It's more an experience/feel thing detecting the change in torque for the change in rotation angle as the annealed (initially very soft) washer is crushed and the material work hardens -- i.e., at the beginning, it takes a lot of rotation to increase the torque much as the soft washer starts to be crushed, but, as it is crushed and hardens, the torque increases sharply with a very small amount of rotation. I know that that doesn't help you at all, but that's the practical reality.

 

The long time accepted method for installing plugs with metal crush washers is to tighten just enough to feel the washer slightly crush or yield.
We just do not see issues with drain plugs coming loose or falling out. What we do see is a great deal of damage from paranoia driven over tightening and thread destruction.

There is a lesson there that is not being learned. I have a drawer in my big toolbox dedicated to thread repair tools. I have helicoil kits for every Ferrari drain plug size and they have been used a lot.

 

Very bad idea. My attitude is if you are too lazy to change oil correctly buy an electric car. Drain plugs exist for a very good reason. Use them.

 

I am also in Canada and drive the same km I Change the oil every 2-3 years I own the car for 20 years and got 82K Miles on it yes Miles in1988
The car came from the west coast with 21k miles
Mil

 

https://belmetric.com/drain-plugs-gaskets/copper-gaskets/

These hollow crush washers seal well in the low pressure drain/fill plug applications with less torque required compared with the solid washers. I found the typical solid copper drain plug washers need a fairly high torque to consistently seal, and it always feels risky to get it "just right". Can't see any downsides, other than them being single use.

fyi, Belmetric also has the somewhat longer reach drain plugs themselves.

 

I am in Whitby maybe I see you in one of the car shows next summer