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The exhaust stud threads in my TS1 are very tired and I am considering repairing them with Time Serts, which I think will be an Improvement on the ally threads. Can anyone tell me if I can use 18mm time serts so that I can use extended studs?

Depending on the pipe you use. Well as long as you use a stub rather than a u pipe. Tap them out to 8mm and use Allen bolts. Far easier to tighten and you can if you like easily drill and lock wire. I’ve used this method for years with no issues.

Dazts1 wrote:Depending on the pipe you use. Well as long as you use a stub rather than a u pipe. Tap them out to 8mm and use Allen bolts. Far easier to tighten and you can if you like easily drill and lock wire. I’ve used this method for years with no issues.

Thanks for the reply Dazts. This approach came up in conversation over the weekend, I've got no strong reasons not taking this route, although i am using a TSR pipe and there is very little clearance between the 11mm head of the exhaust nuts and the bend as it slides over the stub. I will have a measure up. If it works it saves me 120 quid which has got to be good.

I just had to do a mate's to M8 Timesert for his TS1 but cos it has a Gori pipe with a fixed downpipe we couldn't use Allen bolts. The solution is to take an M7 nut, drill to 6.5mm and cut an M8 thread in it with a tap. That way you have an M8 nut with an 11mm spanner size head.

Sticky wrote:I just had to do a mate's to M8 Timesert for his TS1 but cos it has a Gori pipe with a fixed downpipe we couldn't use Allen bolts. The solution is to take an M7 nut, drill to 6.5mm and cut an M8 thread in it with a tap. That way you have an M8 nut with an 11mm spanner size head.

Cheers Sticky, at the moment I've got the option to to use am M7 time sert, or drill out to m8. I could also possibly use Allen bolts, I'm looking to see if I can turn down the heads to 11mm diameter. As I've still got some options open to me which would you go with?

Bobs2 wrote:

Sticky wrote:I just had to do a mate's to M8 Timesert for his TS1 but cos it has a Gori pipe with a fixed downpipe we couldn't use Allen bolts. The solution is to take an M7 nut, drill to 6.5mm and cut an M8 thread in it with a tap. That way you have an M8 nut with an 11mm spanner size head.

Cheers Sticky, at the moment I've got the option to to use am M7 time sert, or drill out to m8. I could also possibly use Allen bolts, I'm looking to see if I can turn down the heads to 11mm diameter. As I've still got some options open to me which would you go with?

If you tap out to M8 it's still an aluminium thread. I think I'd rather have an M7 Timesert if there's still enough aluminium, then any exhaust will fit and you'll have a choice of whichever way you want to fasten it. Others may disagree.

Why not helicoil?

dickie wrote:Why not helicoil?

Thanks for the response dickie,

I've got an m7 helicoil kit, this would be an easy fix, and if I'd had it (and a drill) with me the wrong side of Basinstoke on Sunday, that's exactly what I would have done. But I don't think they are the most robust solution.

I guess the test case is: if I'm on a euro, which repair is less likely to fail in an alpine pass, all of a sudden £130 for time serts might be a good investment.

So is locking a steel thread in an ally barrel the way to go? How good are time serts?

Sticky wrote:

Bobs2 wrote:

Sticky wrote:I just had to do a mate's to M8 Timesert for his TS1 but cos it has a Gori pipe with a fixed downpipe we couldn't use Allen bolts. The solution is to take an M7 nut, drill to 6.5mm and cut an M8 thread in it with a tap. That way you have an M8 nut with an 11mm spanner size head.

Cheers Sticky, at the moment I've got the option to to use am M7 time sert, or drill out to m8. I could also possibly use Allen bolts, I'm looking to see if I can turn down the heads to 11mm diameter. As I've still got some options open to me which would you go with?

If you tap out to M8 it's still an aluminium thread. I think I'd rather have an M7 Timesert if there's still enough aluminium, then any exhaust will fit and you'll have a choice of whichever way you want to fasten it. Others may disagree.

Thats pretty much what I was thinking, but I have never used timeserts, so is a timesert in an ally barrel, better than the original thread? And do we know if a TS1 barrel will take an 18mm deep time sert?

Bobs2 wrote:

dickie wrote:Why not helicoil?

Thanks for the response dickie,

I've got an m7 helicoil kit, this would be an easy fix, and if I'd had it (and a drill) with me the wrong side of Basinstoke on Sunday, that's exactly what I would have done. But I don't think they are the most robust solution.

I guess the test case is: if I'm on a euro, which repair is less likely to fail in an alpine pass, all of a sudden £130 for time serts might be a good investment.

So is locking a steel thread in an ally barrel the way to go? How good are time serts?

If wire thread inserts ("Helicoils") are stipulated in the design & fitted to many aerospace components, then they are surely good enough for the likes of the majority of our repairs.

Fitted correctly, they increase the strength of the threaded hole by having some degree of flexibility along their length, rather than the shear 'spot' loads encountered with threaded holes direct into alloy.

Of course, cleanliness is paramount in fitting.

I prefer to repair with Helicoils because, should they fail, they can often be replaced.

The other consideration is that 'wrenching space' is limited around the exhaust fitting so a good, rolled M7 stud is good to have with an M6 extension nut (pennies from Toolstation) tapped through to M7 with cross lock wire holes.

(Obviously, this good practice is what some of us do in the first place to avoid the need for subsequent repair...... )

Warkton Tornado No.1 wrote:

Bobs2 wrote:

dickie wrote:Why not helicoil?

Thanks for the response dickie,

I've got an m7 helicoil kit, this would be an easy fix, and if I'd had it (and a drill) with me the wrong side of Basinstoke on Sunday, that's exactly what I would have done. But I don't think they are the most robust solution.

I guess the test case is: if I'm on a euro, which repair is less likely to fail in an alpine pass, all of a sudden £130 for time serts might be a good investment.

So is locking a steel thread in an ally barrel the way to go? How good are time serts?

If wire thread inserts ("Helicoils") are stipulated in the design & fitted to many aerospace components, then they are surely good enough for the likes of the majority of our repairs.

Fitted correctly, they increase the strength of the threaded hole by having some degree of flexibility along their length, rather than the shear 'spot' loads encountered with threaded holes direct into alloy.

Of course, cleanliness is paramount in fitting.

I prefer to repair with Helicoils because, should they fail, they can often be replaced.

The other consideration is that 'wrenching space' is limited around the exhaust fitting so a good, rolled M7 stud is good to have with an M6 extension nut (pennies from Toolstation) tapped through to M7 with cross lock wire holes.

(Obviously, this good practice is what some of us do in the first place to avoid the need for subsequent repair...... )

Interesting, are you saying that you drill out good threads and helicoil as a preventative measure?

I have used helicoils for many years and know their worth, my question is are time serts better?

I'm also interested to hear if anyone has used an 18mm deep time sert, as I would ideally like to coninue to use extended thread studs, together with extended wire locked nuts.

I used helicoils on my engine case exhaust stud.I did this more than two years since and its been alright up to press.

Bobs2 wrote:
Interesting, are you saying that you drill out good threads and helicoil as a preventative measure?

I have used helicoils for many years and know their worth, my question is are time serts better?

I'm also interested to hear if anyone has used an 18mm deep time sert, as I would ideally like to coninue to use extended thread studs, together with extended wire locked nuts.

I meant the fact that the 10 mm A/F exhaust nuts are always fitted, regardless of tune, on any engine I work on. If the M7 studs are fitted correctly & the female fasteners made vibration proof via Loctiting, then they will not come loose, unless the standard folded copper/asbestos type junk gaskets are used. Solid copper/silicon sealant or silicon sealant alone will take the heat, oil & pressure......

I don't rip out good threads if I am sure that the male part to be fitted can remain fit for purpose. An example is the studs that are used to hold down the cylinder, where, unfortunately, the threads can become 'baggy' due to wear or simply that oversize studs have been fitted. In that scenario, Timeserts are not as compact, if porting is desired, so I tap out the holes deeper & fit longer threaded studs, such as V*sp# use, (which are excellent quality rolled threads) fitted upside down.

I know what your saying about steel into ally. But with a stub removal is not often needed as you remove springs then remove the pipe. So no in and out wearing the ally out. I’ve had 3 different pipes on this cylinder over the years with Allen bolts and it’s not failed yet. Purely down to not often removing the stub.

Dazts1 wrote:I know what your saying about steel into ally. But with a stub removal is not often needed as you remove springs then remove the pipe. So no in and out wearing the ally out. I’ve had 3 different pipes on this cylinder over the years with Allen bolts and it’s not failed yet. Purely down to not often removing the stub.

I agree that in that any fastener correctly installed & made as 'integral' as possible should be fine, & that is why lock-wiring in the exhaust area is something I have automatically done as a matter of course. As soon as the fastener in a hole can loosen, it will hammer the softer metal oversize. Amazingly, there are 'upgraded' exhausts still available without any anti-vibration mounts designed in, yet there is @ least one expert that markets them, who has elsewhere acknowledged the requirement for a two stroke exhaust to resonate, yet chooses to damp that down, rather than have the benefits, because of the issue of vibration shaking apart their product! Instead, they utilise heavier section sheet steel &/or resort to brazing in the construction

I am sure Timeserts are a fantastic product, but I have always gone down the route of using what I have, due to costs, availability & being able to 'engineer' any modification personally.

That is why I have (in order of size) Helicoils, Tappex Ensats & Camloc Keenserts.

Very rarely, I have had to resort to the Keenserts, but they are probably the most bullet-proof of the solutions that have been discussed here & like Helicoils, a product utilised widely in Aerospace & Motorsport applications.

The last time I resorted to Keenserts was after the two crankcase M8 exhaust bracket mount holes had been 'professionally' welded up & proved to be porous, as is often the case with Lambretta castings due to the high Zinc content.....