That's pretty cool. How long do the engines last under race conditions?

Providing they were maintained well with an oil change every couple of races, sympathetically driven (i.e. hard but not over revved etc) with a season end strip and checkover they could last for many years.

Some would spend far more than that but it was not really necessary at club level. Races were about 10 laps (20 minutes max) and probably 10 in a season so even with practice and test sessions that would amount to well under 1000 miles a year.

Quality components are essential, there is plenty of rubbish out there and also plenty of rubbish machine shops. Find a good supplier and machine shop and keep them sweet.

Even the best engine from internationally known workshops costing more than some complete cars could be destroyed in a few laps by an idiot. One chap had 2 cars at every meeting and it was not unkown for him to destroy both engines or crash at least one. Never had a good finish but a mate of mine made £1000's keeping his cars on the track. He never learnt but kept trying.

Would not surprise me if my best 3 x-flow engines are not still out there. The last I built (and rebuilt after selling it to a mate) went to France to race. The first went to Japan in the early 90's, might still exist I guess. 2nd engine was particularly annoying, always went well but I wanted something with more cc's and power so I found the bits and built one of the best out there. Kept No 2 under the bench for several years but sold it to a mate after he kept pestering me. He gave it a good checkover, fitted one of his own heads and fitted it into a super lightweight chassis. First time out he finished ahead of me which was particularly annoying since he was in a smaller cc class and had less power, but power/weight (and skill) won the day.

Swapped to Mondeo Zetec's eventually for a challange. Wanted to make the car go as fast with a bog standard Ford engine (with Webers etc) as it had with a highly tuned race x-flow. Still got the first Zetec I built under the bench. Out of a burn out for £100 the only parts I changed were the rod bolts to enable more revs safely. Engine stood me at just a few hundred pounds yet made more power than a several thousand pound x-flow. Got some good results but decided to build another with cams, headwork, TB injection, race pistons etc. Went really well but ran the bearings when the oil filter O ring popped out. Sold the oily bits for a profit and fitted a brand new crate Focus Zetec engine. Don't race now, but 175 bhp in a 600kg car is faster than most cars on the road.

No 1 Zetec may resurface when I retire in a project, just got a house to rebuild at present.

www.consumeraffairs.com/news04/2007/01/toyota_slud...l

www.oilsludge.com/

There a dailmer and Toyota sludge issue for you - plenty more examples out there - Saab for instance.

Irrelevant to us this side of the pond. Its for cars before 2002 and in the States they still tend to use old fashioned oils with short change intervals. Miss a change and sludge is still a risk today with those oils.

Use the correct modern oils and you won't have an issue.

The x-flows from scrappers I used to strip all had sumps full of sludge, they probably used some 10w40 or 20w50 mineral oil all their lives. The Zetecs have both been unbelieveably clean and probably used the correct 5w30 Semi Synthetic.

Its called progress.

Regarding oil filters, has anyone any idea what micron rating they have and whether this is a nominal figure or an absolute number.

I'm certainly no authority on it but, I'm pretty sure it differs depending on application or at least that was suggested to me when I approached Mann Hummels technical department some time ago.

Full flow filters will always have to be a compromise between filtration and flow rate.

I do have an oil filter in the garage and it says on the box that it filters to 15 microns.

When I had my Toyota the oil filter had two elements inside, one was a full flow element and the second one looked like a bypass filter.

Edited by Wackyracer on 27/10/2015 at 23:41

I believe all oil filters have a bypass valve, so if the filter becomes blocked a flow of unfiltered oil gets to the engine, better than no oil at all.

That may well be the case now. But in the 90s (and later) one had to check that the new filter for a Pug 205 had a bypass, as some didn't.

And again "a little knowledge can be a dangerous thing"

i read an account of a maint guy who "wrecked" a Caterpillar fleet, by cleverely (he thought) purchasing non-Cat spec oil filters, because they filtered even better than the Cat spec filters.

So that ud be all right.

Cept the Cat spec filters were designed to permit sufficient oil flow.

The finer filter didnt, nor did it have a bypass.

It's not that hard unless your an idiot, all good filter manufacturers have catalogues to tell you which filter they produce to your engine manufacturers spec and if in doubt you can always contact their technical team. I tend to only use Purflux or Mann filters.

My experience.

The 2.0 Zetec in my Caterham cannot use the standard Ford Focus/Mondeo filter with valve in it due to space considerations. For years I had been using the same filter (genuine Ford Escort Mk 2 OHV) which was short enough to fit but did not have a valve and I never had an issue.

Then at a trackday a major calamity happened, the O ring seal on the filter came adrift and 5 litres of Motuls finest was dumped on the track, fellow members were not happy and I had a knocking engine. I know the filter was secure the night before as it was part of my pre event checks.

When I stripped the engine I found the pressure relief valve in the oil pump was stuck in the closed position. The valve allows excess pressure to bleed oil strait back to the sump when the engine is at high revs preventing issues with oil seals etc. Since the filter fitted had no bypass valve there was no secondary way for pressure to be relieved so the oil found the easiest way out by dislodging the O ring.

You cannot legistlate aginst such things happening but I have since located a Mahle filter intended for the Ford KA and Fiesta OHV engines that fits perfectly and has a bypass valve. Fingers crossed for the future.

Dare I ask if your Caterham has an oil pressure gauge?

It does but it needs a better man than me to watch the gauge whilst pushing hard on the track. A glance at the gauges whilst on the straits is as good as it gets.

Got a huge oil pressure warning light but its only good for low pressure, its set at 20 psi instead the OEM 5 psi to give plenty of warning.

For the record Zetecs have very high oil pressure after years of x-flows. A healthy x-flow just rebuilt would have a hot pressure of about 60 psi with revs over 4000. A Zetec manages 80 psi at about 2500 rpm. My gauge only gos to 100 psi and when cold any more than 3500 rpm and the needle hits the stop. That is with 5w30 oil.