sjl1

Blackheath, south east london

Recently purchased from here but never fitted due to change of car, selling Apollo tank, sandwich plate with fitting bolt, all pipework including aeroquip bleed pipe ans rocker cover bleed fitting. Good condition £90 + £10 postage.

Purchased from Caterham last Aug for £260 now for sale after changing car, asking £150 + £10 postage Condition is as new and can confirm decat pipe does improve midrange flexibility and noise

My 310r is currently running on 15” orca’s and cr500’s 6” and 8” which whilst very grippy aren't very progressive. One avenue if thought is to change to 13” wheels and zzs tyres and i have some questions current front cr500’s are very tight (less than and inch clearance) under front cycle wings, how much of a gap can expect with 13’s and will i need shorter stays? How much can i expect to sell 4 apollos and cr500’s, one year old and good tyres? (Anywhere where i could part-ex them) Should i go for 6” or 8”’width on the rears? many thanks

Fair play to Caterham, they changed the plates from carbon to sintered which restored it. I get the impression the carbon plates have been unreliable. Its now working as it should and not noisy

I have previously owned a k series with ford box and now have a 310r with mazda box. It does rattle in 4th but otherwise is very good with a longer 1st (3.0 to 3.6 i think?). Change is excellent and reverse is easier. Whether a 310r is best suited to a 5 or 6 speed box i dont know but can say the mazda box is a good one and an improvement over standard ford 5 speed, it has a sweeter change. I did ask a well known caterham tranmission expert about the rattling 4th and he suggested this is more likely due to the fuelling and a ligjtweight flywheel, an unexpected but interesting answer, i suspect he is in the right track. He did also explain my titan lsd was goosed after 3000 miles! (Which it was). I have also driven another 310r with the mazda box and it had the same rattle in 4th as mine has, so not specific to my car.

Thanks for the replies, think i will cut the head of the bolt with a dremel and just leave it, dont think it warrants removing the inside panel for just one bolt. I suppose i could try cutting the outside end of the rivnut off with the dremel and pushing it through without damaging skin, hmmm

Started replacing the small bolts holding rear wings on with nylon equivalents today and the lower front wouldn't come out and ended up spinning the rivnut which is a nuisance. Can anyone suggest how to deal with this please? many thanks

My 310r bypass pipe has arrived and i am looking forward to hearing how much noisier it makes the car. Am also planning to get it rolling roaded to compare the difference, hoping for improved midrange

I was recently advised by a respected engine builder that for a 310 sigma this was definitely a worthwhile upgrade seeing 10bhp improvements in midrange performance. I have ordered one and will report back

This happened to me recently after switching lights, fan, wipers, screen all in at same time, welded ignition relay contacts closed so ignition wouldn't deactivate. Try replacing ignition relay with one if the others to test. Relays are only a few pounds so worth carrying a spare

Well i burnt my leg rather nastily on that silencer recently exiting the car in shorts and wasn't impressed. Apparently Caterham don't do a sigma pattern heat guard yet which is a shame But its definitely a good idea and i will be getting one soon.

So took car out for a good run today and decided gearbox isnt touching chassis and noise is only on the overrun in fourth, doesnt do it in other gears. Also change improves substantially once gearbox has warmed up. Conclusion is all is well but its still noisy So my question to blatchat is does anyone have experience with using other gearbox oils in their MX5 boxes?

propshaft uj's have oil fling around them but can check again investigating gearbox clearances highlights its very tight on lhs, less than 2mm in places which seems very close, cant image it doesnt vibrate against chassis with these clearances, next step seems to be loosening gearbox mount and trying to pry it over to rhs a bit

Thanks all, oil is clearish yellow and, not blue or red, i think my gearbox change is normal from what all describe, notchy when cold, improving when warm, was similar to courtesy 310r car Noise on overrun is also 'normal' but still hellish loud, im kinda hoping its being exacerbated by contact between box and panels but realise its a longshot, still worth a go. Am thinking of lossening gearbox mounting bolts and prying box over to the right to maximise any gaps.

Well found the drain plug, opened it up and it was full of oil, plenty on the floor by the time i had stuck my finger in to check the level. Looks and smells like the right stuff, not smelly enough to be diff oil. Also lifted the tunnel cover and no sign of gearbox touching frame, about 1/8 inch away from lhs chassis diagonal, cloae but no witness marks on chassis. There is a bulged panel on this side of tunnel providing room for the box which i cant get to, i need a strip of plastic to pass down and test it. If the gearbox did kiss this bulge it would make a great amplifier so this needs more looking at. I am tempted to loosen the gearbox mounting bolts and try levering it sideways More to do

Thanks for all the suggestions, planning to take a look tomorrow after work, hopefully will check oil level and too up plus check clearances, wish me luck

Scott, noise is only on overrun which makes me think it internal noise, but its a good suggestion and got to be worth checking when im down there checking the oil, thanks

Mossy - whilst i appreciate these cars have 'character' this gearbox is far noisier than the type 9 in my old K series to the point it spoiling the experience. Your cars character sounds very similar to mine Jim, thanks for the suggestion, i think i have some spare oil from previous car and will check the level as you suggest, had forgotten the location of filler has changed

Definitely not the diff, which is a BMW LSD unit and has a reputation for being quiet, noise comes from front lhs of gearbox and is worse from passenger seat The mx5 gearbox does however seem to have a reputation for being noisy, it sounds like layshaft rattle on overrun and the courtesy 310 i borrowed was not dissimilar, very noisy, both have light flywheels Oil? When i bought then car the previous owner had missed adding the top bush on the gear linkage, causing it be be sloppy, when i lifted the levers cover to fix this it was full of oil, although i understand this is a separate housing from the main case so not completely conclusive. I suspect it would have seized by now if it was empty, i drive it in the manner intended.

So i have had my 310r sigma for a couple of months now and its settling down nicely but my biggest issue is the terribly noisy (mx5) gearbox. When Caterham did the engine upgrade they said it was normal and to be fair, the courtesy cat they leant me wasnt much quieter. Its a grindy rattly whine on the overrun worse and worst in fourth. I also notice the gearchange isnt great and crunches into 2nd when cold, improves once warm. I suspect all of this is 'normal' but my question is does anyone have any suggestions on how to improve things? its ruining my enjoyment of the car

Fixed it, after checking the caerbont wiring diagram on google i noticed rather unhelpfully the positive and sender connection markings on the loom plug and the associated wires were reversed, this all works until you try to add switched feeds, another example of poor wiring. Anyway, leads reversed and it worked perfectly with sensible temps for oil and water, a nice hack thanks for suggestions

The gauge doesnt register when sender lead grounded so I don't think its a resistance issue, open circuit or grounded makes no difference if i can find the water temp sender i can compare but cant find it?

Am using this http://www.demon-tweeks.co.uk/motorsport/gauge-sender-units/smiths-oil-water-temperature-sender-for-classic-gauges single connection, no instructions ​yes, using existing gauge with switch, have tested wiring and this is all ok

Hi wanted to add oil temperature mod that i had on my old k series car to my new sigma, bought a sump plug with threaded hole doe a temp sender from demon tweeks assuming bog standard sender would work but no joy. Ran wire from sump plug sender to gauge via oil/water switch but nada, water temp works ok but oil shows zero. Earthing gauge to earth has no effect so wondering if these caerbont gauges work differently to old fashioned way? All advice welcomed thanks