Can anyone help with a quick question about oil?

 

I want to order some oil from Shell this morning but could do with some advice.

 

I've got a '91 Jap TT Auto with about 70K on the clock and want to put the oil in that will be the 'best for the engine', and not necessarilly the 'best oil', if that makes sense.

 

I've been recomended by the guy's at Shell Helix Ultra 5W-40 fully synthetic, but from past experience know that fully synthetic oil can sometimes be too good and may be better off with 10w-40 Helix Plus semi synthetic, as the Helix Ultra maybe too thin.

 

Any suggestions gratefully received.

 

Thanks,

 

Nij

castrol 10-60 is the oil ya want bud.

ive a new engine and its the oil i use

Jaylox,

 

long story but i need to get the oil from Shell,and i just need some advice on what grade to get.

 

Thanx anyway,

 

 

Nij

10w40 would be fine imo

 

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I feel the need, the need for speed!

 

10w40 semi synth is running in ours, seems fine, well..no smoke signals anyway

 

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do you think i will be ok on 20w50 ? I think my valve seals are going and want to try something a bit thicker.

Well - I use Mobil Motorsport 15w-50 and I wouldn't use anything else.

 

You will find that if people have had a bad experience with a certain and another one has been better for them, they usually tend to stay with it. However, I have found that the slightly thinker oil is better if you have an older engine and turbos.

 

Just go with your instint is what I say.

id just keep the rating as high as possible

10-60 or 10 -50

with ya engine havin high wear then id keep the oil thick as possible,hot ands cold

 

 

,does anyone no if this affects mpg?

i used a less rating oil as a stop gap and i thought i got better mileage for me petrol

 

Low numbers mean less viscosity at a given temperature. You'll get better mileage but less oil life out of a 5W30 than a 20W50... usually. Again, on older engines, you generally have more friction and wear. My 90NA has 170,000 miles on it, and I use Castrol GTX higher mileage 10W40. Anything less than that just cooks in my engine. Higher viscosity oil also helps seal rings and other components better, and reduces noise and rattling. On worn engines, you tend to get more power back on higher viscosity oils because it reduces blowby in the cylinders, helping to maintain MEP (mean effective pressure) through the stroke.

 

On newer engines, or engines that have used synthetic, it's generally best to stay with synthetic--less friction, more power, better gas mileage.

 

 

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--Maxx

In a 10W40, for example, the 10 stands for low temp. (cold) viscosity, and the 40 stands for high (running) temp. viscosity. The higher the number, the greater the viscosity (thickness). Colder countries require a lower cold temp. grade as they become too viscous at lower temperatures. Warmer countries can use oils with higher viscosities at low temp., although too high is bad for fuel economy.

 

Recent trend with 'normal' cars is for lower viscosity grades eg. 0W20's to improve fuel economy. Older engines are generally not designed, however, for the lower viscosity oils.

 

As oils age in service, they tend to thicken somewhat, especially at higher (operating) temperatures, although this is usually more than compensated for by fuel dilution - not a good thing but it means the aged is is not overall of higher viscosity than fresh oil, UNLESS the oil is severely degrades.

 

The grade to use is usually not critical (look in your owner's manual) as long as you stay within the ball-park of recommended grades. Ferrari's use 10W60 Helix Ultra Racing. Sports cars and turbo-charged cars usually require a thicker oil than standard cars, as the oil will get hotter (and thinner) - so a 10W60 or 15W50 would probably be about right for a 300ZX. Use a fully or semi- synthetic oil tho.

On average, Shell Helix Ultra is £1 cheaper than Mobil 1 and it's probably a bit better. I can get it from work for a couple of quid cheaper still ;-) Don't think I could make it into a Group Buy tho' !! :-(

 

Fully sythetic is dearer (especially with 3-4,000 mile oil changes), but it will be good for your engine and give good performance.

 

At work we believe that Fresh oil is more aggressive towards seals than used oil. Good oils have to pass seals compatiiblity tests.

if you change ya oils every 2-3000 miles does the type of oil make a difference as ya changing it so often(doesnt get chance to degrade so much)

?

Frequent oil changes means the quality of your oil is less important, but there are still benefits of better oils - better fuel economy, more power, less wear, cleaner engine. But you are right to ask, as a major difference between oils of different quality is that they last longer than cheaper ones, and keep performing for longer. That is largely due to higher additive treat rates and better quality basestocks. But you would probably be better changing a semi-synth oils twice as often in our cars than a fully synthetic only once a year.

 

Better oils will probably have more antiwear additives and friction modifiers, which cheap oils probably won't have.

nelson,what oil would you recomend for me?

my engine has done 15k

it has all the usual mods,chip,zorst,filter,boost controller ,intercoolers.

i change my oil every 2-3k

and drive the car hard, very rare

its nice having the extra power but good mileage is also a plus to me.

wat ya think i should go for?ive used rs since i got the car 4yrs ago

cheers jay

With such a new engine, I would say look after it and use a fully synth oil eg. Shell Helix Ultra or Mobil 1. You can rate oils by looking on the side at the API levels - to get to each level you have to pass tougher and tougher engine tests.

 

I would say change it every 3-4,000 miles or maybe a bit more -> 2-3,000 sounds a bit too often 2 me, especially if you use good oil.

 

Think of the oil as the lifeblood of the engine - and it costs very little compared to the whole cost of owning a Z. Cheap oils are a false economy.

 

hth. Dave.

TELL ME ABOUT IT ,IM ON MY 4TH ENGINE!

wot rating shell should i look at?

Shell Helix Ultra 10W60 or similar. You'll have to get it from a Shell service station. This oil is rated at the highest level, but you can compare others with it if you are not sure how good they are. You might see ACEA A1/B1 or similar or API **.

 

The weak point in a turbocharged car is the shaft of the turbo(s). The shaft is very narrow and spind very fast. This causes high local oil temps and if the oil is dagraded or the car is always turned off as soon as the car is stopped, especially after being driven hard, the shaft can eventually coke up and the turbo blows. So frequent oil changes and quality oil are very important when you have a turbo car.

 

turbo timer im my car so ok there

I swear by castrol RS 10/60,2.5 years of it now and no engine probs at all.

 

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KEEP IT SIDEWAYS;).

Thanx everyone for their input.

 

Real peoples experiences realy are much more useful than company spec sheets.

So after reading all the replies I'm going to order the Helix Ultra 10w-60 as that seems to be the most appropriate oil for the car, and certainly won't do it any harm either way.

 

Thanx again

 

Nij

 

 

Nij