Myles Posted May 26, 2003 Share Posted May 26, 2003 Picked up my 1st 7 on Saturday - a 1.6 k-series, 2001, ex-academy (I think) 5 speed with the adjustable spring platforms. Inevitably, I've got some questions as a newbie- some of which might indeed be genuine 'they all do that sir!' situations. So here goes: i) Tyre pressures (groan!). 13" CR500's. The car was flat-floored during its brief race life (only did about three events) and I have the FF results sheet. It suggests tyre pressures of 26psi - which is far higher than the 18psi I thought this forum had decided on for road use. Is 26psi just for dry track use, and is 18psi sensible for road use and reasonable longevity? A related question - I've not got a build manual or even a jack and forgot to ask the previous owner where the jacking points are... ii) Instrument failure When accelerating hard (only noticed it in 2nd and 3rd when life is most frenetic), I've noticed both the rev and speed counters dying/fading only to resurrect themselves when the revs drop in the next gear, or I slow down anyway. AFAIK, they seem fine at all other times - including cruising at fairly constant (high) revs. The needles don't fall to zero instantly - in the time it takes to dispense with 2nd or 3rd gear, they have faded from approx. the 5-6k mark (revs) to the 2k mark. iii) Diff/driveline clonk. I get an audible clonk from the diff area when transitioning from fading throttle to power on. It's not something you can feel (I've experienced driveline shunt in tintops where you can definitely feel as well as hear the shunt). The previous owner said that he had checked it out too and I think he said that Caterham Midlands had explained it away as something they all do... Should I be worried? iv) 'Dead' steering. I drove a 1.6 k-series 5-6 years ago on Rent-a-seven. I remember the steering being ultra-lively in the feedback/kickback sense. My car is extremely stable and doesn't writhe in my hands as I remember the rented one doing. It also doesn't show any obvious desire to self-centre (I only raise this 'cos I've seen it mentioned in SVA reports quite often). Could this be something to do with how the flat-flooring or other suspension set-up tweaks? v) Speedo inaccuracy. Yeah, well. According to my GPS (which I use religiously as a near line-of-sight speedo in my cars), the 7's speedo is overreading by a good 10%. I really don't care about this other than the fact that on my 5000 mile policy, I'm going to be stiffed of 500 miles of driving a year... Is there anything that can be done....? I'll leave it at that for now - I'm bound to find more things to worry about. I would appreciate all replies. Thanks and regds, Myles Link to comment Share on other sites More sharing options...
Sheds Moderator Posted May 26, 2003 Share Posted May 26, 2003 1. a. 18psi is the consensus, I have never had CR500s so I don't know first hand. b. For jacking points see 7faq 2. Dunno 3. TADTS 4. Check geometry, esp toe in. 5. TADTS, if you have a GPS speedo you could just pull the cable off the 'box... Not that I recommend any potentially fraudulent behaviour, and should you come to sell it would be dishonest to claim the mileage as "genuine", unless you were sure that you had only had the cable off for 10% of the time. Link to comment Share on other sites More sharing options...
KenEvans Posted May 26, 2003 Share Posted May 26, 2003 iv) Mine was dead like that when I first built it ie dead steering. I did notice that the ball joints on the uprights were very tightly assembled, it took me a great deal of effort to rotate the joints when turning the tyre by hand with the steering rack disconnected. I think you'll find the feel will improve as everything loosens up - find plenty of roundabouts - but go around them the wrong way too! Ken Link to comment Share on other sites More sharing options...
Myles Posted May 26, 2003 Author Share Posted May 26, 2003 Thanks, we're getting there I think. Searching the archives, I see that other people have had trouble with the dreaded 'backwards tacho' - i.e. it starts to move the wrong way at about 4k rpm. There is a slight suggestion that Caterham swapped out any such tachos in early 2002 (my car was an EU3 spec roadsport factory built in 2001) - are they likely to still do the swap, or am I looking at a new tacho? More questions to follow, I'm sure... Regds, Myles Link to comment Share on other sites More sharing options...
Christian P Posted May 27, 2003 Share Posted May 27, 2003 Myles, re: tacho - Caterham should still do the swap for you, I'd hope. (I had mine done last summer (2001 EU3 Roadsport)). A quick call to their service department will resolve the matter either way... Christian Link to comment Share on other sites More sharing options...
Stuart Faulds Posted May 27, 2003 Share Posted May 27, 2003 re Tyre Pressures - the corner weights should be set with the car as it will be raced, so the pressures should be set to what they will be during a race. Stuart Link to comment Share on other sites More sharing options...
Myles Posted May 27, 2003 Author Share Posted May 27, 2003 Thanks - but I'm using it on the road only at the moment (might track day at some point though)... Regds, Myles Link to comment Share on other sites More sharing options...
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