dry sump lubrication

My old triumph motor bike had dry sump lubrication and it also had various breathers( and oil leaks). Whilst it is true that the return pump pumps 2 or

3 times the amount of the delivery pump so that all the oil and some air is returned to the oil tank, it is a very poor way of allowing an engine to breathe. Various vapours including water , need to be removed from the engine and this is normally done by ventilating the crankcase to the outside ,normally to either the air filter or the inlet manifold , you really dont want the vapours back in the oil tank , you need to get rid of them . Lou Bricant >

Interesting. What car would that be?

You're right though, it needs a breather as just pumping the oil (and it's only oil, even though it might be somewhat aerated) back into the oil tank isn't going to do much to alleviate air pressure variations in the crankcase due to things going up and down and round and round.

Ron Robinson

No, the scavenge pump only pumps oil, not air. Although it will be designed so that it happily handles air or a mixture when cornering, this doesn't remove the need for a breather system.

What is it, BTW ?

Thanks for all your help. The car is a Bentley with the engine tuned for racing. There is a breather hole in the filler cap of the oil tank. I'm assured that this will be enough ventilation, but I'm not sure as its only 5/16ths of an inch. The original crank case breather was through the oil filler cap, but this has been blanked off as it's now a dry sump. Do you think it should have better breathing than this?

What sort of Bentley? There are several different types, built in several different places, but I would have thought that if the engine had been properly 'tuned for racing' there would be a crankcase breather and it would lead into a catch tank of adequate capacity to meet with the approval of the scrutineers. Take a pipe from where the oil filler used to be and run it to a suitable sized can which is vented to the atmosphere.

Ron Robinson

If you can post to the RREC or BDC forum, you'll probably get an answer from Alan Padgett - and what he doesn't know about building Bentley engines for racing really isn't worth knowing.

Please tell me it isn't one of those hideous Mk VI specials...

....No, its an 8 litre WO Bentley. It's the size of a small steam engine and it's a real monster! Like all monsters it belches smoke and fire, and the roar is enough to burst any unsuspecting ear drums within a radius of 50 yards. (I have may have empoyed just a little artistic license here!) I'm visiting it this weekend with all your helpful comments under my belt, and well, we'll see ..... Thanks to everyone who has posted so far.

Rubbish, the scavenge pump pumps a mixture of air and oil back to the holding tank, where the air is allowed to rise out of the oil. The engine sump is connected to the holding tank so a vacuum doesnt form in the sump.

Tim. .

You may have seen a system where the crankcase was connected to the oil tank by something other than the oil return pipe, but in many years of dealing with dry-sump racing cars I haven't, but then most of the ones I dealt with had the tank at the opposite end of the car to the engine. If they are close to each other, yes, you could perfectly well run a pipe (not the oil return pipe, a separate breather pipe) from the crankcase or the old oil filler to the air space in the oil tank. Talking of which, it's a good idea to use some sort of centrifugal arrangement for separating the oil and air on their return to the oil tank.

Ron Robinson

Now that's what I call a Bentley....

(apologies to Paul Hogan)

Ron Robinson

Last year I was driving the DS through a local village, keeping nicely to the 30mph limit, when some little scrote in a tarted up Saxo decided to act the big man to his 15 year old girlfriend (*) and swerved past me.

As soon as we were out of the village I stuck my foot down and within a few seconds he was a dot in the rear view mirror. As I passed him, the thought which came unbidden to my head was "You call that a Citroen?

*This* is a Citroen."

Ian

• I didn't see her, but I think it's safe to assume that all modified car drivers have a 15 year old girlfriend. It's why they fit play stations - a Barbie Malibu Beach House would be more appropriate, but maybe just too embarrassing.

Ha! Many years ago when the world was young and there was such a magazine as 'The Motor', a chap called Brockbank used to draw marvellous cartoons for them. One of his most famous was entitled 'Citroen Presse' (sorry, can't do an acute accent on this thing) and depicted a Traction Avant, Michelins screaming and leaving black lines around the corners, being pursued along an Alpine road by a 4 1/2 litre Bentley. One of my favourites, that. Ranks with his other one of a similar Bentley passing a modern car and the passenger lighting his pipe with a match struck on the modern's roof as it does so.

Ron Robinson

Right, well, I'm off to drive the monster this weekend, does anybody have any advice? I'm told the gear box is 'a bit of a pig!'

Well, that's a relief - but I'm not still not convinced about modifying one. What coachwork did it have originally?

With 8 litres, you hardly need the gearbox - just start off in top :-). I've never driven anything quite so old or splendid, but even on the later cars, you start off in 2nd, and can let them dawdle down to a few mile/h in top, and still pull away smoothly. The steering might be hard work at low speed - it depends how used you've got to being able to turn the wheel with the car stationary, as people seem to with modern cars. Don't forget to retard the ignition when you start it, then advance it most of the way as soon as it's idling.

I'm very, very jealous...

I have a couple of his books. I like the one of the man trying to keep away RAF jets with a "No Hawkers" sign - when they are replaced by flying saucers he adds "No Circulars".

Ian

In news: snipped-for-privacy@q2g2000cwa.googlegroups.com, Helen wittered on forthwith;

Just out of interest, you weren't featured in C&SC a few years ago were you?

I remember reading about a Helen who liked to thromp about in vintage Bentleys. [1]

Rare breed, women with taste in cars [2]

[1] As in drive... [2] That should earn me a slap, but it's only Usenet.

Now that is my kind of humour. I'll have to watch out for his books.

Are they still in print, do you know? Or am I going to be looking in second hand shops and book fairs?

Jim

Jim Warren ( snipped-for-privacy@OMITblueyonder.co.uk) gurgled happily, sounding much like they were saying :

Is that a yes or a no?