Can I ask what you mean by warming up?

Do you mean letting the idle for a few minutes?

I think he means drive off boost till car is up to temp

This


Oil temp is the one to go by not water temp so much. The standard water temp guage will show when first warming that conversley you will have some warmth in the oil. But what temp it is the oil at???

Personaly I drive off boost with lots of mechanical sympathy up to 80degrees
Start to give it a bit more up to a working temp of 90degress (All depends on what engine). Thrash the guts off it up to 120degrees ...and then I think about calming things down.

Modern oils coat the components when cold. So one could argue the above is not totaly necessary but to counter that, the majority of long term damage is often done to an engine in those first few cold minutes.

Driving slowly is better for the car than letting car warm up stationary on the drive

I have seen more mate lol. I have a rep for being a bit of nutter :D

Harvey used to say 130 was where he would back off!

Those temps were on forged 2.5s driven untill the brakes faded or the oil cooked running a 16 row mocal cooler, group N baffled sump, 10mm oil pump and a large return to sump catch can
(Oil was 10w50 Fuchs ester synthetic)
2.5s tend to run hotter by about 10degrees at least mind.
Having a six speed in classic doesnt help wih under bonnet temps either

Current forged 2.1 with a 16 row mocal cooler, group N baffled sump, 11mm oil pump and a large VTA catch can - I expect to see lower temperatures from. We shall see.
Also having a big fcu k off red warning light placed on the dash. Set to remind me, once the oil starts screaming´´Steve STOP driving like a **** and back off´´

Isn't oil pressure more important than oil temperature. If the outside temperature is within the viscosity rating ie 5w30,10w40 etc then the oil should be the correct consistency anyway from cold,shouldn't it? (I'm not saying you shouldnt let things warm up before a thrash but isn't that more to let metals warm up and components) What kind of temperature does it take to boil oil and make its properties worse

The flash point of an oil varies e.g. the Silkolene Pro-S has

5w-30: 193C
5w-40: 195C
10w-50: 210C
10w-60: >200C

Shell Helix Ultra flash point
0w-40: 215C
5w-30: 215C
5w-40:215C

The flash point means **** all IMHO, I've found the Shell to be oxidised (sent it for analysis) after only 3k miles and not even having exceeded 102C!!!

Of course it is not an esther synthetic and I only used it twice (in winter only) and stopped ever since.

I've been using Silkolene Pro-S since then and the analysis showed all was well.

Unless ones sends his oil for analysis you never know if the oil has had it or not.

ScoobyJim
I would say both are important.
Many people with out oil pressure monitoring in car fire up the car and think nothing of it.
When I crank it cold with no spark it can take about 30 seconds for the oil system to pressurise up to the correct pressure.

As Fivos(Fpan) has pointed out flash points are high I think Motul has even higher flash points from memory. But the hotter it is getting the thinner it is getting....and the oil temp in itself might not be the end problem but it is showing you things are generlay getting way too hot down there and something might fail.

Once on a forged engine of mine that began to hit high oil temps for instance the end blew of a NGK 7 and did the head. (that cylinder was running too hot and when pushed hard something eventually went)

So if the flashpoint is not something to go by and your oil was no good and it only got to 102c then what temperature won't ruin oil? For example I use castrol magnatec 5w30 or 10w40. How often would you have to send oil for analysis,surely you would just change oil if you was concerned about it rather than have it tested?

But isn't oil pressure created by the oil pump which surely is only pumping when engine is running,so what is cold cranking achieving? I would've thought that is worse. Just start the car and let the pump do its job.if engine has sat along time without a start I could understand turning crank over by hand first. Also isn't thinner oil better than thick oil? If the oil temperature got dangerously hot then wouldn't that make the engine block hot which would heat the water/coolant system anyway and make the water temperature gauge go up? The ngk 7 is apparently for standard boost cars and rule of thumb is every 70-100hp extra really requires one grade lower plug, which for ngk is a 6. Otherwise you chance pre-ignition from plug igniting fuel before it sparks due to ceramic part getting to hot.this is fatal to engines! A hotter plug is ok for short journeys but for longer journeys like lots of motorway driving or track a colder plug is better

Things like the Viscosity Index (VI) and HTHS are much more important in how the oil resists in "wear and tear"

The Shell Helix Ultra is a group III oil whereas the Silkolene Pro-S a group IV.

I tested my oil out of curiosity, this is something that haulage companies do; testing the oil is a lot more common in US within car enthusiasts as well.

Why continue using the same oil if it breaks down and not use a better one?

The NGK 6 is the standard plug, 7 is a colder one.

The choice of viscosity depends on the use of a car, for an everyday car a fully synthetic 5w-40 is better than e.g. a 10w-50 or 10w-60 but for a car that spends most of its time on a track the latter might be better than the former.

I use my car daily and currently use 5w30 so that's ok. You're right about the ngk 7,he already has the colder plug,my bad ;)

Any info and opinions for castrol magnatec 5w30 & the 10w40

You have this a bit back to front- thinner oil isn't better than thick, it depends on how the engine has been built, the bearing clearances are the main factor e.g. more clearance needs thicker oil. The heat rating on the plugs are 6 as std, a 7 is a colder plug not the other way around.

For the piston clearances yes, but what about main end bearings?

The clearance on the latter is standard isn't it?

Doesn't that mean a thicker oil (even in a forged engine) makes the bottom end wear faster?

There are many forged engines out of the factory (found in some Audis, Seats etc.) whose owners use 5w-30 (recommended OEM viscosity). Don't these engines have big clearances?

Crank clearances are critical for oil choice, not so much bore (piston) clearances. Yes some engines have forged pistons from the factory, but they may be a higher silicone type which can run tighter in the bore. Thicker oil won't wear the engine out quicker, it's all about setting the whole build up for the desired use.
I have many enquiries for builds were the Customer wants a 600bhp spec build but they only want to run 400bhp. They think it's better to be stronger, but what they need to understand is they way you build a 600bhp engine is differnt to a 400bhp engine.

Do you mean that the crank clearances in most forged Subaru builds are bigger than in OEM Subaru engines?

Even in a "basic" forged build whose owner wants to run 350/360 bhp and e.g a standard or nitrided crank is used?

No, this is something the engine builder will spec, we all have our own ways of doing things so not everyone will use the same method.
As an axample, for a 350-400bhp engine I would run 4032 pistons at 0.002" bore clearance, acl duraglide bearings (std clearance) and use 10/40 oil. For a 600bhp rac car I would run 2618 pistons at 0.004" and run acl race bearings slightly loose and 10/60 oil. Both with 11mm oil pump, shimmed in the race engine for extra pressure.

I asked my engine builder to do this! He told me the engine he was going to build me would be good for 400hp but I want to run power close to that,so i wanted engine stronger,so he called me a few days later and told me what he was now going to build would be good for 500hp. I wonder what differences he made then if its a different way of building?

Yes sorry I've corrected myself already on this thread about the ngk ratings,thanks anyway. I personally would think thicker oil is best because if its more likely to quieten a tapping engine then it must lubricate better than thin oil but someone once described to me that thicker oil makes the engine work harder,its like trying to walk in water or even worse custard lol as opposed to walking through thin air

The main thing going from 400-500 is better headstuds (400 is ok on std bolts), the other thing is pistons, I would use 4032's for 400 but 2618 for 500, this would mean more bore clearance.
thats what I would be doing but your engine builder should tell you anyway.

Thinner oil does give less resistance, but if you run it in a high power build you would need to think about rebuilding more often, as it would'nt give as much protection as a full competition 10/60 would.

I never thought to ask him about clearances etc. The only thing I know about the pistons is they are forged teflon coated but nothing about measurements

Next time mines due a change ill be putting a thicker in then :thumb:

What are the benefits of thin oil then if thicker lubricates better

I think he means that only forged engines with high tolerances should use thicker oil.
standardish engines with small tolerances i'd use a 5w-40.

Kershaw I'd highly recommend Alan J, if getting some quotes and probably one of the most helpful guys on here IMHO when I need any advice on my Hatch (along with Rob of course).

I've done exact same with my hatch mate (forged), as quite simple couldn't find another car that I fancied after driving the hatch for 2 years. With regards to the clutch question as unsure if anyone posting reply on it, I was advised std one is fine up to 380 and certainly not anymore than 400. When my engine was out getting forged I just got upgraded clutch as cost of labour greatly reduced.

Im confused,think im just going to use a 10w40 lol not a 5w30 or 10w60

Modern engines are designed to run tight bore clearances and thin oil to help with emmisions and overall effeciency. You should really use a thicker oil with a high power build for better protection. But this is down to how it's built though, every builder will have their way of doing things.

what clutch did you gfo for aas dont want a proper raceing clutch i had one on my old 350z and it was horrible a juddery and just not nice to drive at all