Obodiah Posted March 18, 2020 Share Posted March 18, 2020 I've just taken delivery of my 420R kit and although some way off I was wondering why half the rear wing fixings are rivnuts and the other half are machine screws / washers. I get the point that rivnuts have to be used where there is no access behind a panel but is there a problem if I use rivnuts for the remaining fixings ? Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted March 18, 2020 Member Share Posted March 18, 2020 Are you intending to use nylon screws? Many of us prefer them because they fail on impact with no or less damage to the body and wing. Some even cut into the side of the screws to weaken them further.Jonathan Link to comment Share on other sites More sharing options...
Wrightpayne Posted March 18, 2020 Share Posted March 18, 2020 Rivnuts have a tendency to spin with age as ally with a ferrous / stainless fixing can seize (dissimmilar metals) so coppa / alu slip the bolts.While the back of the rivnut will be accessible in the boot if they seize, a nut and bolt is easier to manage. I put the nut on the arch side so there are no 'snags' in the boot (something you'd get with rivnuts). Just my 0.02p worth! Link to comment Share on other sites More sharing options...
Blue C7 Posted March 18, 2020 Share Posted March 18, 2020 If you use rivnuts for the other fixings the end of the rivnuts and the bolts will be sticking into the boot area Link to comment Share on other sites More sharing options...
StevehS3 Posted March 18, 2020 Share Posted March 18, 2020 I screwed M5 eyelets onto the protruding bolts and use them as tie downs. Link to comment Share on other sites More sharing options...
Obodiah Posted March 18, 2020 Author Share Posted March 18, 2020 Great, thankyou. All makes sense, I like the eyelet / elastic idea, I never would have thought of that !Are nylon screws OK for the IVA ? Link to comment Share on other sites More sharing options...
ChrisC Posted March 18, 2020 Share Posted March 18, 2020 I would not change anything before IVA, but fully intent to swap to nylon post, also your washer bottle is now located in that corner. The big question is how are you going to screw your rear light on, the self tapping screws bite the wing and crack the gel coat. I think I have found a way to work round it, but haven't posted it on the blog yet. I am using rubber backed domed washers and flare nyloc nuts and bolts (M4) which clear the hole that's normally drilled for the self tapper. Also helps with the new requirement to secure the wiring between the light and the skin. Link to comment Share on other sites More sharing options...
David White Posted March 18, 2020 Share Posted March 18, 2020 I used M5 bolts for the rear lights as I didn't like the way the self tappers damage the gel coat. Link to comment Share on other sites More sharing options...
ChrisC Posted March 18, 2020 Share Posted March 18, 2020 For my wing M5 would not clear the hole drilled by Caterham, so M4 it was. The rubber backed washers are M5 to allow them to take up the angle. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted March 18, 2020 Member Share Posted March 18, 2020 Are nylon screws OK for the IVA ?Sorry, I don't know.Jonathan Link to comment Share on other sites More sharing options...
Dixa1225 Posted March 18, 2020 Share Posted March 18, 2020 Nylon are fine for IVA Link to comment Share on other sites More sharing options...
Obodiah Posted March 18, 2020 Author Share Posted March 18, 2020 Thanks again. I'm not a big fan of self-tappers either and will either drill & tap or use nuts and bolts instead. Chris - I'm avidly following your blog as you're finishing just as I am starting. The rear wing solution is interesting. Link to comment Share on other sites More sharing options...
Wilts North AR Posted March 18, 2020 Share Posted March 18, 2020 The weird thing about the rear wing fixings & to me goes against all engineering principles is that the build manual suggests that the bolts are passed through with the head in the boot. Better to have the bolt passing the other way so the nut & thread end is not exposed to the road but also for uniformity. OK it will mean either shortening the existing bolts, purchasing suitable shorter ones & if this practice is carried out actually having to accommodate one of the nuts by trimming the boot floor.Spent some time doing this when I built my car & it looks right. Link to comment Share on other sites More sharing options...
Wrightpayne Posted March 18, 2020 Share Posted March 18, 2020 I just used stainless instead of the supplied zinc plated fixings - no corrosion no seized nuts and bolts. Rivnuts may be a different story! Link to comment Share on other sites More sharing options...
ChrisC Posted March 18, 2020 Share Posted March 18, 2020 Thank you, took a massive step backwards last night with an electrical problem :-( Minor, but an IVA check so needs must. Instruments out and wiring every where to find the problem. Apart from that I would have been ready for my original IVA date of the 20th, my current date is the 1st April but I am just waiting for the email / call to cancel that because of the virus. Link to comment Share on other sites More sharing options...
Obodiah Posted March 18, 2020 Author Share Posted March 18, 2020 Good luck, hope you get it sorted. Link to comment Share on other sites More sharing options...
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