replacing +2 sills

[Hawksfield]

Hi all

I have just replaced the driver side sill for the second time since 1987 decided on the Spyder sills and I am pleased with the quality and substantial build.
The sill installation was straight forward removal and install with the body in situ, I did this job previously with the body off so was pleased it was just as easy body on. I had some work to do on the GRP floor so all carpets had to be removed on the drivers side, this was the longest job to replace carpets and underfelt after glass fibre repairs.
Near side sill to be carried out in the next couple of weeks as I have to do a bit more in the garden.
This side should be easier as there is no floor repairs to carryout.
See images of sill out and in

removing sill

sill entry

In position ready to push finally home single handed

[wotsisname]

What prompted the 2nd replacement ? more specifically.. which bits have rotted first and any thoughts on treatments to prolong life even further. Your second set lasted slightly longer than the factory version. I have the spyder variant, which are heavily galvanised.. am considering if waxoyl is worthwhile...although Im thinking it wont be the main tube that rots.

[Hawksfield]

Hi wotsisname

I bought the car in 1986 and immediately set removing the body this is when I found the original sills corroded at the Jacking points. when I actually removed them I found the bottom section of the sill was corroded along the the area of the 11small bolts, they were 15 years old.
This year on removing the drivers side sill because of damage to the grp floor section adjacent to the seat belt anchor plate I found them in the same condition as in 1986 which is around 33 years. The design is not the best at keeping water out of the sill casing so it is quite common to experience this the sills I replaced at that time were mild seal and just undersealed as what was available then. So the second set installed by me lasted twice long as the Lotus OE type. The galvanised set I have now installed will see me out unless I reach 107 years old. The problem is water will always lay in the bottom of the sill and as the jacking entry is open to the elements so will be corroded just the same, the galvanised sill installed now will help with SS bolts. there is SS sills available but I think the Spyder give a lot better impact protection.
Waxoyl can only help if it runs along the bottom bolted joint to protect the bolts I dont think Spyder sills will be a problem you can also remove the cover plates and treat them periodically.

[alan.barker]

Imho the only way to go is Stainless Steel. When you drill the holes for the Screws along the bottom it's no problem with Stainless.
If the sills are normal steel where you drill the holes it will be exposed metal to rust.
Imho it's also a good idea to make new closing Plates from Stainless or maybe Alloy.
The galvanised Sills for sure will last a very long time and don't need any additionnel treatment.
Alan

[mbell]

Imho it's also a good idea to make new closing Plates from Stainless or maybe Alloy.

I make mine out of sheet ABS plastic, saved about a lb per closing sheet and can be cut with strong scissors, doesn't requires paint, cheap and don't rot. They probably will go brittle and need replacing in 20 or 30 years thou.

[gus]

I put spyder sills in in 1984, they are as new, still

[Bigbaldybloke]

I’ve got stainless steel sills installed with stainless bolts and alloy closing plates sealed in place. I’ve not got holes through the fibreglass sill for the jack points at present but the sills are marked if I want to drill them. I have a different jack but also breakdown recovery if needed! Not too worried about the stainless sill not being as strong as the galvanised version as in any kind of side impact there is nothing but the fibreglass shell linking the sill to the central chassis so pretty sure that’s the weak point not the sill member.

[Mrozik]

Many thanks for the info. It prompted me to have a look at mine - wow see photo, not much left! - I guess they were the originals from 1968?