another oil question

[racingmjl]

hi all my cerbera speed six has now just turned 40k and i always top up with mobile1 0 40, should i now use a thicker oil like 15 40 thanks mark

[Far Eastender]

I'm up to 34K now and the TVR main dealer servicing the car has changed to 5W40 (Motul oil).

[ajcj]

I use Castrol Magnatec 10w-40. The selling point of Magnatec is that it has an additive that clings to metal surfaces (not quite magnetic, but you get the idea), so when you start up there is still some protection before the lubricant gets pumped round the engine. I've seen the results of a great many scientific tests that prove this works. This seemed like a sensible move given the S6's well publicised issues with oil starvation in the top end. Twenty quid for four litres, cheaper than Mobil 1 too!

Time to declare an interest - I've worked for Castrol for nearly ten years, so you can think either "he would say that, wouldn't he", or "he might know whereof he speaks". If it makes any difference, I left earlier this year and I'm still buying it.

[andyoleary]

Is Castrol Magnatec fully synthetic? Just curious,

Andy

[ajcj]

No, part synthetic (or semi-synthetic).

Synthetic oil is primarily useful for helping to get good oil performance over longer drain intervals at thinner viscosities, which the motor manufacturers like because it helps to lower fuel consumption figures, and extend service intervals. I'm not convinced TVRs need synthetic oils, although they can't hurt - just why pay £15 per litre when you don't need to?

[brem]

@ajcj

I'm also looking for a good oil for my Tuscan S and I'm interested in Castrol Magnetic. Also looked at Castrol Edge, it's a motorsport oil. So which one would you recommend for my Tuscan with a lot of trackdays?
I think the Magnetic is very good for cold start and warming up but is it also good on high temps and high revs like on a trackday?

thanks..........Peter

[dogbucket]

Fully synthetic ester oils like Silkolene Pro also have 'Electrosyntec' properties as they call it ie. the oil molecules are attracted to the metal to help cold start situations. Plus you get the high temperature performance as well.

[ajcj]

brem said:

@ajcj

I'm also looking for a good oil for my Tuscan S and I'm interested in Castrol Magnetic. Also looked at Castrol Edge, it's a motorsport oil. So which one would you recommend for my Tuscan with a lot of trackdays?
I think the Magnetic is very good for cold start and warming up but is it also good on high temps and high revs like on a trackday?

thanks..........Peter

I would put a full synth in for that kind of action. Have a look at Edge on the Castrol.com website - they have done some peak performance longevity tests. The 0w40 should be fine, but you could go for the 10w60. Lots of motorsport nuts use it.

[Tangoed]

Had a rebuild from TVR Power and they recommend semi-synthetic and 15-40w. The 0-40 is to thin and not recommended, only for running in. It was stressed never put fully-synthetic in a speed six.

[andyoleary]

Never put fully-synthetic in a SP6? Eh? Did Dom say that? Did he mention that specifically for a re-built/running-in engine or for all SP6 engines?

Confused.com

[Tangoed]

Never put fully synthetic oil in a SP6, running in or otherwise. I'd always used Mobil 1 and asked what I should be topping the car up with, thats how I got to know his thought on this issue.

[andyoleary]

That is interesting. I thought full synth was the norm.

Anyone else have any comments/thoughts on this?

Andy

[scooterscot]

We use Castrol 10w 40 in all the cars we sevice, have done since it came out. It improved the Rover V8 cam wear problem and is much better in the other engines as well. There is no piont in fully synthetic oil if you are changing it every 6000 miles. Modern oils can do the job for 6000 miles and it is better to change it often to remove the waste products produced in the engine. John Ravenscroft told us it was the best oil for the engines but contracts with other companys to support racing was the reason for other oils being promoted.

[FrancoTam]

I've just had my car serviced at Racing Green and had 0/40 Mobile 1 oil put in with a powerful magnet on the oil filter to take out any debris. Is this seen to be bad?

[Tangoed]

I would of put the same oil in mine fully synthetic, and would of thought its the best money can buy for the emgine. But for some reason and I dont have the answer, is that part synthetic is recommended. Is it something to do with being or having mineral based oil, and if this is the case at high temps dosnt it burn as oppossed to fully synthetic.

The nind boggles

[ajcj]

FrancoTam said:

I've just had my car serviced at Racing Green and had 0/40 Mobile 1 oil put in with a powerful magnet on the oil filter to take out any debris. Is this seen to be bad?

Not bad, exactly....

Mobil 1 is a very good oil in many ways. The question is: why use synthetic (or not)? Synthetic base stocks are primarily used to achieve stable performance characteristics at lower viscosities. Engine manufacturers are under pressure to extend the times between oil changes (to keep ownership costs down), and to achieve the best fuel economy possible (ditto, plus legislation in some countries [CAFE in the US]). Lower viscosities (0w and 5w) are desirable because thinner oils create less friction in the engine and do - just about - therefore contribute to better fuel economy. To achieve a thin oil that lasts a long time between changes, you need a synthetic base.

Why might this be a problem? Well, if your engine was not designed with those ends in mind, it won't particularly benefit from a synthetic oil. The fuel economy benefit (or increased power, if you like) is pretty minimal, so unless you change from a 10w-60 to a 0w-20 you won't notice a difference, and a TVR doesn't really need the extra 1% efficiency anyway.

More importantly, many synthetic oils are designed to keep engines free from the build-up of deposits that occur as a result of combustion (think soot), so they can pick them up and carry them in suspension. If you have an older engine, these deposits may be the only things sealing the less-than-blueprinted gaps in the various bits of your engine. Put a thin, aggressively cleaning oil into an old engine and you might find more of it on the driveway and in the cylinders than you might expect!

So, after a long lecture, I would say you haven't done the wrong thing, but you have spent more money than you needed to, you might get higher oil consumption than you otherwise could have, and you are missing out on the benefits of the Castrol Magnatec that I mentioned in an earlier post.

[Tonymg]

Dear ajcj

i'v got and still have my old MGF VVC 1.8 i use Castral Mag and know i got an old aug 2001 Tuscan had a re-build by Power 5 months ago and i was thinking of changing the oil 3k after each service.

with Castral Mag but what type? numbers that is i just use the TVR at weekends or when i can in the week well you know how it is 8-) i dont do track days just normal driveing keep to the speed limets 8-(

hope you can help

Tony......

[Tonymg]

Dear Me

Well just put two cans of Castral Mag 5-40w in it,s oil so the engine shud be ok.
i don't race around just drive brum brum.


Tony...