Which Oil is best - Semi or Fully

[gofasterrosssco]

Hi,

Looking to have an oil change done on my recent car purchase. Problem is that it is a Jap import with an engine that was never sold outside japan (3S-GE BEAMS), therefore the users manual is in Japanese also.

So to cut a long story short, am I better with semi-synthetic as is good for most 'modern' engines, or is fully synthetic generally better all round and has no disadvantages.

Not too concerned about price; I dont do many miles per year, but short trips to work and back. Also the engine makes 200hp from a NA 2.0L so I'd imagine the oil doesnt get an easy life cooked up in there..............

Help appreciated

Ross

[rustybin]

Short trips, highly tuned engine (I'm guessing high revving?). You sir, will be wanting the fully synth. With a bit of luck Opieoilman will be along soon to tell you (given a little more info) precisely which one.

[Mr E]

On a BEAMS 3S-GE, a good quality fully synth mate.

Cracking engine.

[gofasterrosssco]

Thanks. Bought 0W/40 and got it put in. The garage then told me I shouldnt be using that rating because its too thin and i risk excessive internal wear......... Im getting them to put 5W/40 in now; £60 for a change is better than £3k for a new engine I suppose....

[tuttle]

Mr E said:

On a BEAMS 3S-GE, a good quality fully synth mate. Cracking engine.

100% Agreed
Fully synth, am a Millers fan myself.

[denisb]

tuttle - Which Millers oils have you used? I am considering going to the 10/60 on my race car next year, any ideas if it is any good?

[MGBV8]

The triple ester 10W60 works well with a B race engine.

Too thin ?

[randtis]

gofasterrosssco said:

Bought 0W/40 and got it put in. The garage then told me I shouldnt be using that rating because its too thin and i risk excessive internal wear. Im getting them to put 5W/40 in

The garage is talking cobblers. Both those oils are the same viscosity when hot.

When cold, the 0W is thinner than the 5W and is therefore the preferred choice.

[tuttle]

denisb said:

tuttle - Which Millers oils have you used? I am considering going to the 10/60 on my race car next year, any ideas if it is any good?

The Millers is ester based & ,comparatively, not bad value,only seems to come in 4ltr cans which can be a pain. Am presently using,(& have been for a couple of years), 10/60 competition oil in a modified 2.5ltr turbo straight six (skyline).Works fine. For road use I change it out about every 4-5k & it still looks fairly 'fresh'.

[gofasterrosssco]

randtis said:

gofasterrosssco said: Bought 0W/40 and got it put in. The garage then told me I shouldnt be using that rating because its too thin and i risk excessive internal wear. Im getting them to put 5W/40 in The garage is talking cobblers. Both those oils are the same viscosity when hot. When cold, the 0W is thinner than the 5W and is therefore the preferred choice.

Yep well I do alot of cold starts so maybe a higher viscosity oil when cold is better. They actually put 10W/40 in, so now im thinking its too thick................

I think the manual, that is 95% Japanese, says 5W/30 or 10W/50. Not overly bothered as its a fuly synthetic and im more concerned about possible accelerated engine wear than losing a couple of HP...........

[MGBV8]

In general 70% of engine wear is attributed to first 15mins after a "dry" start. One issue is oil flow

a few observations with a 0W30 oil

definitions:
Minimal Flow - some lubricity first noticed after "dry" start.
Full Flow - oil gushing from lifter.

Observations:
@ approx 60F:
211 cSt
Minimal Flow: ~25 sec
Full Flow: ~55 sec

@ approx 20F (
936 cSt
Minimal Flow: ~60 sec
Full Flow: ~160 sec

In winter I would therefore prefer to run a 0W or 5W oil to aid circulation.

At operating temperature a key indicator is HTHS (oil viscosity at 150c). Ester based oils give a higher HTHS than other types of synthetics of similar 100c viscosity. Redline Motul 300V Silkolene Millers are ester based oils. For normal road use an HTHS of 3.6 is usually specified so an oil like M1 0W40 would both have the required HTHS and good cold flow properties