Gridgway Posted October 23, 2023 Share Posted October 23, 2023 For my 85 home built bitsa BDR it's a huge mix of imperial and metric nuts and bolts. Are there any resources about the major components and what should be used? And then similar with the ancillary fittings. I know on the ancillaries bolted through things you can use what you like. The builder and subsequent modifiers have used a lot of metric bolts. As a side and probably very dull story, I was confused by a bizaare happening. I wanted new k-nuts for my inlet manifold for the carb fitting (the PO used a weight saving device of only 5 nuts for the 8 stud). I thought for some reason that they were M8 rather than 5/16th unf. I ordered them. Then a mate said, no way they'll be 5/16th. So I got to work with my metric thread gauge and easily found the studs were indeed imperial (imperial gauge on order). Then I checked the nuts and they fitted a 5/16th unf test bolt and not an M8. So the metric k-nuts I bought are imperial. Thanks Link to comment Share on other sites More sharing options...
rj Posted October 23, 2023 Share Posted October 23, 2023 This might be useful (with an assembly guide for your car), which you might be able to download from http://www.caterham.dk/Assembly_Guides/index.htm 1 Link to comment Share on other sites More sharing options...
Gridgway Posted October 23, 2023 Author Share Posted October 23, 2023 Brilliant, thanks. I will look and digest. Link to comment Share on other sites More sharing options...
OldAndrewE Posted October 23, 2023 Share Posted October 23, 2023 On my 1985 S3 there is nothing of any significance that is metric (the screws/nuts holding the wings on may be metric). 1 Link to comment Share on other sites More sharing options...
anthonym Posted October 23, 2023 Share Posted October 23, 2023 me too - spent ages acquiring imperial over here. Back in GB I had a "has everything imaginable threads shop" where I practically lived during my 2012 (approx) rebuild. Link to comment Share on other sites More sharing options...
mikestifel Posted October 23, 2023 Share Posted October 23, 2023 It's all fun and games until you encounter the BA hardware in the windscreen. Link to comment Share on other sites More sharing options...
Wrightpayne Posted October 24, 2023 Share Posted October 24, 2023 (edited) If its a dedion the lower diff mounting bolts are ‘special’!! They have a 1/2” imperial shank (to fit the chassis bush) and a metric thread to fit the Ford differential. They will be, I suspect, a machined / re-threaded 1/2” UNF bolt. I found on a friends seven that the previous owner had fitted normal metric bolts giving about 1/2mm of play in the bush. Obviously the clamping force would have contained this to some extent but not ideal when you’re pushing well over 200hp through the 8” rears! There are also some specific thickness washers between the brake caliper and front upright (I think they are referred to as ‘pink’ in the manual) which fill a gap where the back plate would be clamped on the Triumph. Ian Edited October 24, 2023 by Wrightpayne 1 Link to comment Share on other sites More sharing options...
OldAndrewE Posted October 24, 2023 Share Posted October 24, 2023 1 hour ago, Wrightpayne said: If its a dedion the lower diff mounting bolts are ‘special’!! I should add that mine is a live axle (English Ford) 1 Link to comment Share on other sites More sharing options...
Gridgway Posted October 24, 2023 Author Share Posted October 24, 2023 28 minutes ago, OldAndrewE said: I should add that mine is a live axle (English Ford) As is mine 1 Link to comment Share on other sites More sharing options...
Gridgway Posted October 24, 2023 Author Share Posted October 24, 2023 I think I'll start a spreadsheet to record what I find. I expect it's mainly all the ancillary bits that are metric. Bolts to hold the coil on, the rev limiter box,, the facet pump, the (bolted) p-clips etc. They are all too long as well!! Should I replace all of those with imperial or leave be I wonder? 1 Link to comment Share on other sites More sharing options...
anthonym Posted October 24, 2023 Share Posted October 24, 2023 (edited) Oh. Mine’s dedion. I used stainless where possible, washers esp.my main tools were a bench wire brush, sandblasting cabinet and clear lacquer. Edited October 24, 2023 by anthonym Just add more Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted October 24, 2023 Share Posted October 24, 2023 (edited) 5 hours ago, anthonym said: Oh. Mine’s dedion. I used stainless where possible, washers esp.my main tools were a bench wire brush, sandblasting cabinet and clear lacquer. Hi Anthony, with stainless steel fasteners it is great to use them for low stress areas, but I assume you didn’t use them for high stress areas such as the suspension or engine mounts? Standard unmarked stainless steel bolts are only around 500MPA, compared with the lowest strength normally used carbon/alloy steel 8.8 or Grade 5 bolts at 830MPA and the higher strength commonly available 12.9 or A574 bolts at 1220MPA. Even expensive and hard to obtain A4-80 stainless steel bolts are only 800MPA. Edited October 24, 2023 by aerobod 1 Link to comment Share on other sites More sharing options...
anthonym Posted October 24, 2023 Share Posted October 24, 2023 (edited) no noooo exactly as you say. (that's what "where possible" meant) Edited October 24, 2023 by anthonym 1 Link to comment Share on other sites More sharing options...
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