oil for crossflows

[budgie]

Can anyone tell me if mobil 1 motorsport synthetic oil is o.k. for crossflows.I see in the Burton catalogue they seem not to recommend it,but say to use Valvolene 20-50 Racing . Any experiences to relate?

 

 

[grease monkey]

Mobil 1 Motorsport was recomended to me by Roger King after some recent engine work

[Phil]

It is perfectly ok to use 0w/40 MOBIL 1 in your car.

 

The engine will take a while to warm up from start at room temp for example to its optimum running temp even longer if it is cold as in winter, during this time the most engine wear occurs. The best way of of preventing this is to use an oil with as low a first number as possible ie 0w, the engine as it gets to its best working temp and above will need the oil to keep its ability to lubricate and disperse heat with the ability to move very fast and keep up with the engine as it revs hard.

 

To make an oil perform to these requirements the oil needs a helping hand from man, when they take out a lot of the impurities and add parts to keep the oil together we call this semi synthetic

When man starts afresh with synthetic ingredients and designs the oil using no base crude oil this is called a synthetic oil.

 

A semi or full synthetic oil will outperform a mineral oil over a service interval because it has good shear quality, this means that with a lack of impurities the oil strings slide past each other without snagging and braking up, longer strings of oil make for better lubrication.

 

The most commom mistake made by people and MECHANICS is that changing to a synthetic with a very low number will cause drastic leaks all over the place, rubish, heat any oil and this will increase its viscosity [speed at which it flows] giving the impession that it is thin so why does this not leak when hot.

 

When our engines were designed 50s/60s the only quality oil available at the time was 20w/50 but our engines are now still the same design but with better quality materials and tighter tolerences possible because of better quality oils.

 

20w/50 racing oil maybe fully synthetic but it is still slow moving at start up so why use it as one it is overpriced and two it is out performed by many other oils.

 

I use a fully synth 5w/40 in my car a 1990 1700SS DD with no problems and in my Audi, a 1978 Cavelier coupe and my 1974 1.6 air cooled VW camper van, no leaks no problems.

 

The reason I use 5w/40 is because you get 5ltr for a sensible price, supplied by Halfrauds own brand made by I thing Comma, Comma themselves, Duckhams[4.5ltr] AC DELCO etc MObil 1 is still one of the best but at £33.00 for 4 ltr a little much and Castrol now produce one called RS 0w/40 at £27.99 for 4ltr to match Mobil 1

 

 

[Simos]

Mobil 1 is fine for your crossflow.

 

0/40 is better suited for lots of starts and short blats without monster revs.

 

15/50 is better for "track boy" mentality (that'll be me then) where 10 mins oil warming time is all that keeps you from testing that rev limiter (again)

 

As noted before if it's synthetic and from a decent manufacturer there's little to choose between them. I doubt you'd see much difference between that V20/50 and M 15/50 given you're "track boy".

 

That said there are people on the forum who notice the difference between Comma and Mobil1 and who's to say that for their engine there isn't.

 

Bottom line is there are more crossflows, BD's, VX's and Zetecs on this forum running on Mobil1 than you can point a stick at. We'd know if it were pants.

[ashaughnessy]

How would we know if it were pants? How do you measure the effectiveness of an oil? Difficult to run back to back tests with different oils in the same engine under the same conditions and measure the wear from each.

 

I wouldn't normally pick up on such a point, but lots of advice on this forum could be described as "received wisdom" or even old wives tales. The usual thing goes like this: "I run mobil 1 in my crossflow. My engine hasn't blown up yet. Therefore mobil 1 is a good choice for the crossflow." This isn't logical. A lot of advice on techtalk is like this.

 

I'm not saying Mobil 1 isn't good (it's what I use in my crossflow) and I'm not saying that you're not qualified to say it's good. Just making a general point.

 

I'll get my coat :-)

Anthony

[Graham Sewell]

Over the years of running various xflows (I had a Mk2 Escort once) my attitude is that the recommended 15W/40 is perfectly good for the average engine upto Caterham factory spec. But if you get the engine rebuilt by a specialist with finer tolerances and higher spec componenets (e.g. forged pistons) then the 'higher quality' oils such as Mobil 1 become useful.

 

I guess it also depends on you usage of the car - e.g. road use is not as stressed and high revving as track use so it can survive on lesser oils.

 

Low tech luddite - xflow and proud!

[Phil]

A mk11 escort is the same engine but as I said what oil was available when it was in production, it maybe the same engine used in the Caterham but this is a modern version of this already using uprated materials and tolerences and higher revs. If you check out an oil manufatures guide book they will always state the minimum requirement oil and the better alternatives.

If you were to read the blurb on the side of a 20w/50

oil it will say that it is designed for the older higher milage cars and even though this oil is over thirty years out of date and should not be used in a modern engine, people still think that 100 thou miles is high and wrongly buy it not knowing that it does not contain enough additives to meet the demands of a modern engine thinking only that they have saved some money.

Fully synthetic oil, you can afford it, simply think

less engine wear less repair, better lubrication better performance and more BHP, less friction more miles per gallon. It pays for itself.

 

 

[Phil]

Nicely said

"can survive on lesser oils"

you to can survive on chips and beans but wouldn't you and your engine rather be healthy and live longer?

 

 

[Alex Wong1697456877]

There is a theory that engines running rich - eg all carb engines at anything less than full throttle - have problems with oil being washed off the bores by petrol. A friend with a strong engineering background strongly advised me against using full synthetic in my old x-flow as he had problems with this and suggested that good quality mineral oil or semi synthetic was a better choice.

 

 

 

Edited by - Alex Wong on 22 May 2002 11:51:22

[Casbar]

We can only make decisons on the advice of others. Roger King recommended that I use Mobil 1 in my modified xflow.

 

That's good enough for me!

 

Used to use mineral oil before the re-build

[Phil]

Alex, are you or your friend trying to say that fully synthetic can be washed away by petrol and semi synthetic [half synthetic] and mineral oils can not?

 

 

[Peter T]

Personally i prefer to use non synthetic oil in my x-flow, i just use 15/40 castrol and would rather change the oil more frequently than opting for extended oil changes that you gain with synthetic oils.

I also beleive that x-flows do not need low viscousity oils as they still have rather large engineering tolerences compared to modern vehicles.

 

C7 PWT X-Flow all Steel

Life begins at 40(00rpm)

[Phil]

The idea of a semi or fully synthetic is to cope better with the stesses of any engine, better at disapating the heat and more resiliant to brake down causing less start up wear and keeping the engine clean. The job of the oil is also to keep in suspension small particals and soot produced by combustion and take it to the filter and not deposit it in the sump etc, a semi or fully synthetic is much better at this.

The engine manufaturer calculates how long it takes for the engine to produce this amount of dirt/soot etc and how much the filter can cope with, then sets the service interval required safely within the limits.

I would not recomend a longer service interval than recomended no matter what oil you use, shorter service intervals do have lots of benifits.

I cannot remember exactly but I thing oil starts to brake up/burn about 90degres and engines run at 100degres plus so the better the oil the more resiliant it is to this.

 

 

[Graham Sewell]

My personal choice of oil is the same as Peter T's - with a change every 3000 miles. In tin tops, the change frequency is between 6000 and 12000 miles (depending on car manufacturer) so I reckon it will cope easily with 3000 road miles without any real problem.

 

Low tech luddite - xflow and proud!

[Roger King]

We recommend Mobil 1 racing in Crossflows for lots of reasons, but this doesn't mean that some other synthetics won't be just as good. It's just that when you find something that works, you tend to stick with it.

 

We don't sell Mobil 1, so there is no commercial motive here.

 

It is 15W/50, so is reasonably free flowing when cold, but the greater viscosity helps to maintain oil pressure when stinking hot on track. There is also the fact that it will better maintain a film on the camshaft when switched off than thinner oils - this doesn't necessarily matter on an OHC engine where oil tends to puddle around on the followers, but on a Crossflow these bits are all up in the air and tend to drain dry - not good for starting.

 

Theoretically, it's good to 130 degrees C, but we like the temp to stay below 100 degrees C in practice.

 

The age of the engine design is not really that important if the maching and bearing technology, etc, is to modern standards. Bore and ring finish technology being on a different planet now compared to the 60s; if these are good, borewash will be just as bad on synthetic as on mineral. I suppose you could make a case for old fashioned oil in a really old splash lubricated engine (Austin 7, or am I mistaken?), but I am a bit cynical about these 'classic' oils on the market. I'm damn sure they'd have used the stuff we have now if it had been around then.

 

I make no claim to having any expert knowledge about lubricants, other than as a user. There is no doubt that engines run on synthetic are much cleaner internally when stripped than those on mineral oil.

 

However, I don't think there is much point in changing to synthetic if you already have substantial miles under your belt on mineral.

[Dirty Den]

Hi Roger -

 

I've been reading this thread with interest as I've not had my 7 long. It's a 95 1600 xflow, Sprint. I changed the oil and put in a mineral Castrol GTX oil (10w/40 I think). As the engine has only done 9000 miles, is there a good case for me moving to Mobil 1 or some other synthetic oil?

 

When I did the last change, I just wanted rid of the old oil in there wink.gif where the car had been in storage, so put in a mineral, with the intent of changing later. Now I've read some of the pro mineral comments, I've been wondering what to do.

 

Mainly road use with the occasional track day.

 

You mentioned 'Mobil 1 racing' - 15W/50 did you say? Is the normal Mobil 1 0w/40 a bad idea then? Can you pick up this Mobil 1 racing oil in Halfords, or is it more specialist?

 

Thanks for any advice,

 

Den

 

 

teeth.gif - Self portrait - still unable to remove the smile!

 

Edited by - Dirty Den on 22 May 2002 17:16:54

[Simos]

Anthony,

 

take your point however my inferrence was to collected experience not just mine. I agree there is no scientific way of collating this and about the best you'll get out of the website is that no one has pointed the finger of blame at ANY oil as being reponsible for blowup/excessive wear. Which is reflected in the earlier part of my post which says I doubt you'll tell the difference between any of them.

 

However to counter your point "how do you know", "how do you measure" I'll ask you to reflect on the feedback from EBC Greenstuff pads (which I happen to have fitted). There is a clear feedback from many sources that while they are advertised as the dogs danglies and whilst they do what they say on the box they are not foolproof, not the best (pagids are?) and overheating them on the track will kill them - something which isn't printed on the box. Reasonable feedback I think from a unmeasured, uncoordinated test.

 

No it's not scientific, but it gives you a pretty good idea which is what I was alluding to. 100's of 7's must have mobil1 in, if it were pants... we WOULD know.

 

As to the actual oil, I said "Mobil 1 is fine for your crossflow" I didn't say it was the best choice, I specifically avoided that and said in effect you can pretty much run anything but make it heavier if you thrash it. I don't think there's a simple answer, you'd have to know if it were a rebuilt all steel monster or a knackered lump from an '83 XR3i for starters.

 

No you can't really know without doing testing although I have tested non-, semi- and synthetic oils in the same engine under the same conditions with a rebuild between each and noticed the difference so it isn't all made up.

 

There, have I qualified it enough smile.gif.

 

The feedback from this site IS generally apocryphal (except when PC writes). It usually gets a concensus by the end of the thread though, it's upto you to see the concensus and make your choice.

 

Cheers, Simon.

[James Arnold]

Surely the Xflow was never fitted to a XR3i and I don't think it had the 'i' in 83 either.

Err, have I missed the point here?

J

[eric]

My 1600 sprint engine was running before with agip semi syntetic 10W40

 

Now with full syntetic 15W50 Motul.

 

The engine sounds better and very important, the oil pressure when hot at iddle is higher.

And for that reason I will not revert to a thinner oil

 

The only thing is to warm your engine before using high rev.

 

For the fact of oil washing by the petrol (weber ), Some people (oil specialists) told me that a syntetic oil is better than a mineral.

 

Today I have heard too many things which seems opposite, so my advice is :

try to find a semi syntetic 15W50 (no risk)

But anyway you can trust Roger King with:

15W50 Mobil 1

there is also Yacco Galaxie and Motul all 15W50

 

I hope it may help

 

Eric

[budgie]

The original question was about mobil one "motorsport"15/50 oil.Is this what Roger King meant when he said Mobil one "racing"Its just that Burtons said dont use the thin(i assume 0/40)synthetic oil as crossflow tolerences are large.

[eric]

The Burton advice is very simple :

 

If you go racing the better for us is valvoline 20W50 because it is a thicker oil which mean that at high rev and for a long time the oil film is more resistant.

But as it is a mineral oil you must drain it at the end of the race

 

For a more common use 15W50 syntetic is the best because it is not a thin oil and as it is a syntetic oil it resists much better to be washed by petrol.(also Burton advise)

 

In france, we do use in competition 15w50 in this engine.

The Motul give you good smell

 

 

0W40, 5W50, 10W40 or 50 is, from my point of view too thin

and could damage the engine, of course when hot and in summer.

 

 

Caterham recommands 15w40 semi syntetic, less expensive than a 15w50 syntetic and without danger.

Another thinking : when people tell you do not use syntetic in a crossflow they speak about current one, I mean 0W40 ....

 

Anyway it is not difficult to try for a short period in your engine.

I hope it may help

 

Eric

[Roger King]

Yep, sorry, I should have said Mobil 1 'Motorsport', not 'racing'. Would you take advice from a man who can't even get the name right?!

 

The standard Mobil 1 is 0W/40 and the motorsport version is 15W/50 and we prefer the motorsport version for all applications in a Crossflow. Our local Halfords sells the Motorsport stuff, but I don't know if they all do.

 

Dirty Den, if you are sure that your engine has had regular oil changes in the past and hasn't been running on sludge, synthetic would probably be a good idea. This is for a 1600 Sprint - a 1700 Supersprint is likely to be half way to being knackered at 9000 miles so I don't think I would bother to change to synthetic on one of those. It's not a lubrication thing with Supersprints that causes problems, but one of piston/ring failure.

[ashaughnessy]

Simos, I accept your qualification :-) I hope you don't think I was being too personal. It was a general comment really.

Anthony

[Phil]

1 It does not matter how many miles your car has done if you want to change to a semi or full synthetic do so.

 

2 Please forget the words thick and thin as it should be slow or fast.

 

3 All the oils you speak about are multigrades made to cover cold starting and hot running tempreture and inbetween.

 

4 A fast [not thin remember] moving oil will not cause leaks, it will just move around your engine faster on start up to reach all the parts required quickly.

 

5 The second reading example 40 or 50 is the viscosity reading taken at 100 deg plus meaning it will keep its filming/lubrication qualities and viscosity at these tempretures.

 

5 The reason an oil will becombe faster is that some or all of the impurities have been removed so the strings of oil will flow past each other smoothly, benifits are they do not snag on each other and brake up, this is called shear quality, the better the shear quality resulting in the oil performing to its best for longer into the service period.

 

6 Additives are blendid to make the oil perform to its best under all conditions by helping to keep the strings of oil together under all conditions and tempretures and stop evaporation. Also to keep particals in suspention.

 

7 Detergents are there to help stop oxidation of oil building up on the metal surface causing bad lubrication [example noisy tappets] and to combat the side effects of combustion in the form of acids and soot.

 

8 Engines have come a long way in developement and require better lubricaion so the better the oil available the better the engines become.

 

So what do we want from an oil?

less wear at start up as the engine takes time to warm up.

Protection from heat when sitting in traffic or moving on a bit.

The oil to perform all the way through to its recomended service interval.

To keep the engin clean.

 

So the lower the first number cold start protection

not thin but fast remember getting to the top end quicker for the cams and hydraulics

 

Second readin higher number viscosity to protect when hot for charging about or sitting in traffic.

 

A semi or fully synthetic for better resiliance to brake down keeping the engine clean.

 

The first numer quoted on the grading is the viscosity from cold indicated by a W this is to represent winter the symbol for cold, this viscosity reading is taken at minus twenty degrees C.

The second reading is for hot tempretures giving the oils viscosity reading at 100degrees C plus.

 

Idealy when hot the higher number is required example 50 but with modern engines which rev a lot higher the oil will also have to move faster to keep up with the mechanical parts so a lower number will be required as the oil is faster moving and more able to cope, hence 40 for example.

 

A 20w grading is very slow moving form cold giving poor engine protection from cold and is not used these days and sales are droping off, this oil has a low specification as there is no point in improving on a oil that will not sell. The biggest reason for the oil still being sold as much as it does is the common misconseption that it is thick and will cure leaks and sales staff without any knowledge of there products.

 

20w/50 fully synthetic oil is specific for racing where the engine is warmed up before racing and with the bonus of the engine being rebuilt on a regular basis, not much good for road and race or just road use.

 

Brilliant example is the ford OHC engine designed in the 50s with only 20w/50 available to it at sensible price and capable of about 80thousand miles. IN 1983 the engine was rebuilt using far better materials and better oil and this engine when treated correctly is capable of 200 thousand or more and has only recently been replaced.

 

 

 

[Simos]

Anthony,

 

You kidding ? smile.gif too many people take things personally on the forum blush.gif I've no problem with people telling me I'm talking bollocks, afterall, they're probably right.

 

James, twas just an example of a typically old knackered beast, I don't know whether tws or twasn't I think you're probably right. I thought they were around when I started Uni as the 'car to apire to' for the essesx boy students teeth.gif - but now you mention it, maybe it was later.

 

Cheers, Simon.