diggerman

Thank for the various comments. It is a four lead sensor and my 150 is definitely a pop banger, I suspect its this aspect that is the destroying feature. I have read somewhere that the sensors can be cleaned by leaving them immersed in petrol. Mine has come off the car looking rather black which indicates the engine is running rich, but that may be due to the sensor having failed. Might try cleaning an old one, just out of curiosity. In answer to some of the questions, I have not noticed increased fuel consumption, the engine burns no oil and all the exhaust joints are free of sealant. Will post if cleaning an old sensor miraculously restores it to life. peter

My car is coming up 10 years old and has done 30,000 miles. It seems to eat lambda sensors, the third one has just failed! Anyone else with similar experience? Whats the best price you have been quoted for a Bosch original. My local supplier has a GKN equivelant. Any experience of those? Peter

I built a 150SV in 2010. It took a year or so for Caterham to get the mapping right and I ended up upgrading the transmission to BMW - the silent diff, bliss. The car has now completed Just short of 30,000 miles having toured, France, Belgium, Germany, Switzerland, Spain, isle of Man and most of the UK. That version of the Sigma with throttle bodies is outrageously raucous complete with over-run pops and bangs, but it has been completely reliable and if anything, gets better with age. I have driven Premier Powers 175 with throttle bodies and a light flywheel. If you want a completely crazy car, that's the power unit to go for and the only alternative to the 150 I would consider. Give Stuart at PP a call and spend your cash on his upgrade. He's a nice bloke too! Peter

Stuart at Premier did my 150 Roadsport at 6 years 20,000 miles. Its not a simple job, definitely needs an expert like Stuart.

Have had a Starcom set up with headphones and boom mics for eight years now. Sound quality is great, they are comfortable and the wife is happy. Have used them extensively in France and Spain without problem. I fitted everything myself, including bulkhead plugs, it was relatively straight forward.

Have had a Starcom set up with headphones and boom mics for eight years now. Sound quality is great, they are comfortable and the wife is happy. Have used them extensively in France and Spain without problem. I fitted everything myself, including bulkhead plugs, it was relatively straight forward.

Built my car in 2010 and used silicon. All the rubber edges are still in place. Could be that your surfaces and silicon are too cold. You should be able to use enough so that it the excess squeezes out then can be neatly shape with a clean finger. If you get it wrong, let the silicon set, then it will peal off. Good excuse to warm the garage. Peter

Lots of interesting comments on the 150. All I can say is I have now done 26,000 miles of wonderful faultless, exhilarating driving with mine. Its been more or less bomb proof, is easy to drive in all circumstances, there are no flat spots or other bad habits AND the soundtrack complete with pops and bangs on over-run is just amazing. The one upgrade I would consider is Premier Powers 175 with light flywheel. That's another universe. The ultra light Sigma engine is a great basis for a Caterham. I suspect this would have been Colin Chapman's choice over the Duratech. peter

For the record I have a 150 that I built in 2010 and has now done 24,000 miles. The original mapping was a problem. When new the car wouldn't start at all. Caterham re-mapped it and it ran rough. Subsequently in the first 6 months they re-mapped twice more and each was a vast improvement. The final version has been brilliant ever since. The lambda seems to have a life of about 10,000 miles. When they fails, engine running becomes rough and hesitant, particularly at low and medium revs. The fault doesn't appear in the first 90 secs from start up as the ECU isolates the lambda for that period. To get home you can unplug the lambda and the problem goes away, but don't leave it like that as you will damage the cat. I have also found the wiring to the lambda to be fragile and open to being damaged by rubbing on the underside of the cill. I have resolved that problem by enclosing the wiring in split 1/4 inch rubber tubing and sealing wires and plug with insulating tape. The 150 seems to be hard on plugs. I had a plug failure that produced a misfire that I hastily, and wrongly diagnosed as lambda failure. The symptoms are similar so I suggest that you keep a good set of used plugs and try these before investing in a new lambda. Finally I have to say my 150 is an absolute joy to drive. It has loads of power and torque, and the sound track with over-run pops and bangs is just amazing. It has taken me and 'er on many a long tour inc France, Switzerland, Spain, IOM and just recently, Ireland. The lambda is the only item that occasionally fails, so I carry a spare. It seems a shame that Caterham didn't persist with the 159, but the few that exist must surely be destined to be collectable rarities. Peter

Any motor factor can identify a filter from this: Oil filter Fram PH10044 ​Peter

I've just spent a very pleasant few hours with Stuart at Premier Power while he replaced the cam belt on my Sigma 150. Just watching a master craftsman at work was an experience in itself, but that pleasure was surpassed when Stuart sat me in the seat of his 175-ti-vct demonstrator - and let me drive it! Apart from being wheelspinningly quick, that engine delivers power smoothly over a very wide torque band, and winds up to the rev limiter (7400rpm) in an instant. Compared to my 150 it's simply a different animal, much faster and more tractable. Interestingly though, its a pussycat to drive in restricted areas and traffic, that makes the car a great all rounder. I have always been convinced that the Sigma characteristics are well suited to a Caterham (dare I say compared to a Duratec). There is no doubt that the 175 demonstrates just how good this little engine is, and what miracles are possible under Premier Power's hot breath. if you want a great experience, suggest you give Stuart a call and see if you too can blag a test drive. Be warned though, you will be tempted ....... Peter

Kingsley, the early filler tubes were too small in diameter and made it impossible to get easy entry for a standard unleaded nozzle. The later tubes complete with flap can be re-fuelled without problem. The flap is there for an important safety reason and in my opinion should not be removed. peter

No good ....... That only fits an SV

My banner battery lasted 6 years, but always with a conditioner connected whilst car not in use. Peter

I have used the trick mentioned above by SM25T. A short piece of (I think 1inch dia) plastic waste pipe fitted in to the loop on the throttle pedal then hand crafted to suite your foot and heal and toe style. Works perfectly. Have also pop riveted a 1/4inch wide piece of aluminium sheet on the tunnel adjacent to the clutch pedal, to act as a foot rest. This saves ankle ache and avoids riding the clutch on long trips peter