Stripped gearbox mounting plate studs - time-serts vs helicoil?

[ross.mcw]

Hi all,

Recently sold my business and have retired so figured it was time to get my '72 2.4T back up and running - unbelievably it's been almost 20 years(!) since I purchased the car via this forum - I just can't get my head around that at all!

It's been 2 or 3 years since I last had it out so there's a few things I need to sort.

The first issue was fuel pissing out of every possible place. So a friend and I replaced all the fuel lines which fixed the leaks however, the fuel regulator was showing 6 PSI (vs. the recommended 3.5) and adjustments weren't having any effect.

We pulled the regulator apart to find that the brass thingy-ma-bob and spring under the regulator's diaphragm had dropped into its bowl which was a bit disconcerting but we re-assembled it, adjusted the pressure and it's all good now. Engine running again.

But in order to get better access to where the fuel line connects to the tube going through the body, we dropped the anti-roll bar and gearbox mounting plate and two of the bolts came out along with the threads from the gearbox so I need to fix these now.

After doing a bit of research, it seems like time-serts may be the better - albeit more expensive - option than helicoils. Having no experience with either of these myself I just wondered what advice others here had? I believe my gearbox casing is magnesium rather aluminium - does that have any bearing on the choice?

Thanks in advance and hopefully I'll be spending more time on this forum again now!

Cheers, Ross.

[Gary71]

Hi Ross, Timeserts are reputedly stronger, but for example I've got a helicoil in one of my box to engine fixings (in magnesium) and it's been fine for 10 years plus. For head studs pulled from the case etc then 100% go timesert as the loads are massive.

The fixings you mention don't support the weight of the box as such, so are 'only' dealing with box movement under load. I wouldn't hesitate to put a helicoil in assuming the hole size hasn't ended up too large with the pulled thread.

That part of my box is aluminium rather than magnesium, but I think it's been swapped at some point!

[Northy]

I stripped the threads on my gearbox to body mount. I had about 3 threads left. Drilled out and a helicoil fitted (I didn’t fancy it without a ramp and a local garage did it, for minimal labour). No problems since and I’ve had the bolts in and out a few times.

[Loz]

Hi Ross,

I've just done a Timesert in my magnesium gearbox and it's gone in very well and looks to be a very satisfactory install.
It had been over drilled before so it needed an M12 Timesert.
Hope this helps.

Sent from my Pixel 8a using Tapatalk

[hot66]

Ross, which car did you buy all those years back ?

[Mike911scrs]

Hi Ross
just be careful when drilling the end case, as at least one of the stud holes is close to going through into the inside of the box,

I would use TimeSurts at the correct length,

also check for cracks in the casing from the stud holes.

or change the end case for a better one, casing, seal and a gasket,

if you do get a case, don't forget to swap the speedo drive parts over, for the speedo to work correctly

regards mike