What is the consensus on Sigmas engined 7's and track days?

[Green George]

I noticed a topic which covered this recently, either here or on one of the many facebook groups, and of course cannot find it now.

Simple question (hopefully), are Sigma engined 7's susceptible to oil starvation during high speed sustained corning i.e. on track e.g. like K Series and Duratec engined 7's?

Popped into Caterham Cars South to look at the very nice Riveira Blue SLR to find it had been sold and ended up trying on a Superlight 20 and a couple of 310R's which appear to be very nice packages, but I am not familiar with the Sigma engine.

[downsman]

I do at least one track day a year in my Sigma 125. The first thing I fitted after the build was a 21psi warning light, and it has never flickered during track use. The first couple of times, I had my passenger watching it!

However, the stickiest tyres I have used were a021r Yokohamas. I can't say what would happen if you used ZZRs or R888.

[Master Bean]

Mine has been fine at Castle Combe although I have nothing to compare it with.

[anonymous-user]

Plenty do run wet sump engines with no apparent problems but the consensus is that if you're going to do regular track days a dry sump is much better and safer.

Having said that you presumably have the Caterham wet sump which seems to be reasonably well baffled.

[PAULJA]

When you look at how many sigmas run in the numerous Catherham race series I guess they must be up to the job. I know of one racer that has raced / tested / done tackdays for a full 4 years and he's still on the original engine. The race cars do run a different breather system to the standard car.

[Green George]

That is very interesting. I had thought the race engines would have been dry dumped. Thank you for that.

[SKC]

We've run F200 (200bhp) Sigmas running at 8000rpm on track with ZZRs. We've had no problem with surge. We've also developed our own dry sump system which is a very neat installation and reduces the "risk"!! of engine damage due to surge.

In testing we've found the dry sump system reduces the maximum oil temperature by 20 degrees C which has to be good for the engine. This is still with us running a Laminova heat exchanger set up on both the wet sump set up and dry sump set up.

Regards

SKC

[Green George]

Thanks for your input Stuart, that is very helpful.

George

[HustleRussell]

This season I've raced a Supersport 140 in the 'Sigmax' class of the Graduates club, there are approx. 30 cars with as many as 20 turning up per race weekend. All, as far as I know, have wet sumps and the revised windage plate from Caterham. None have suffered oil starvation related issues.

A few seasons ago, Sigma engines particularly the 140 were ejecting all of their oil and spinning bearings for fun. The engines only take about 3.5l of oil and with heavy track use they were blowing their dipsticks out and spontaneously jettisoning the lot. The combination of the upgraded windage plate from Caterham and a simple spring or zip tie to keep the dipstick in seems to have resolved this problem completely.

[downsman]

That's interesting, there's 5 litres of oil in my Sigma 125 sump!

[HustleRussell]

downsman said:

That's interesting, there's 5 litres of oil in my Sigma 125 sump!

With open breathers it'll chuck all the excess into the catch tank and find its level- about a quarter of the way up the scale between 'min' and 'max'. I sometimes get a twitch on about oil level and put 100ml or so extra in but one 20 minute race later it's breathed another 100ml into the catch tank...