Ultra_Nexus

Yes, I know my name isn't Brian. I'd imagine on what oil you use is the primary limiting factor, and how well it resists shear. A decent ester based synthetic is what you want.

MB

Tell me more Hyper Im am quite into tribology....

MB

Ultra_Nexus

Well, if I had my way, i'd coat the piston in PTFE, and mangnetise both the liners and the surface of the piston both the same polarity so as they repelled each other. This should take some of the strain of the rings during crank rotation when the crank is perpendicular to the cylinder (viewed longitudinally). The thing is, you can't just bin oil, its too good at what it does. You could indeed coat everything in PTFE, but it will wear out, which means you lose tolerances and then then have to replace everything within a very short time. With the oil, it all floats. When the oil 'wears out' we change it which is a 30 mins job. The problem with everything I have listed is temperature. Its so hot inside combustion chambers the PTFE would probably come off as its limit is ~250

Sailaway

so back to my original ? wot is average life expectany of a F20C when used reasonably revved to red line fairly often ect ect ?

On the oil thing which seems to have raised a few technocrats heads above the parapits, whiy did my engine not lke Mobil 1burnt it like it was going out of fashion the only advantage might have been for Mobil as I would have changed the oil every 3 thousand miles at that rate !!
No porbs with semi syth though.

Strange many years ago had lots of probs on industrial gear boxes with Mobil Synthetic Gear Oil they had to Change the oil twice putting problems down to manufacturing, Noise was un believeable @ oil temp of 55c supposedly well within spec

mikdys

My take on it is that you should be safe if you look to get 100k from the engine (if you get any more that will be a bonus ).

As for the oil burning this has to be because oil labled (word chosen carefully) as fully sythentic is thinner than the semi-synth'. I don't see that this is a bad thing though as long as you keep the level regularly topped up (driven hard my car uses about 1litre of Shell Ultra every 1,000 miles but this doesn't worry me as I think its normal when the early engines are revved high).

Sailaway

The most likey reason for fully synth oil appearing to be thinner for a given viscosity is that the viscosity is far more stable over a wider range of temp than a mineral or semi synth oil.

For sure the more the eingine is revved the more oil is likey to get past the rings, I have noticed this if I have used lots of revs over a particular 1000miles. But on average still about 250ml's per thousand.

Lots of press about Vauxhall/GM engines using gallons as a result of factory using Synth from new not leting engines bed in, resulting in huge oil consumption up to

Sailaway

To continue ,thats why Honda ue ordinary mineral oil at first in the F20C with special additives, and it is important to keep this in till 6000miles to let all surfaces bed in in the engine. GM should take note but I suppose they dont care if the driver puts

MB

How is mixing synth and mineral oil bad? "Pure" synthetics maybe....

When it comes to oil there is an extreme amount of misinformation on bulletin boards!

"fully synth is thinner than semi" Ok, how does that work?! It depends on the viscosities at given temps!

I work closely with Castrol and Air BP, and have trialled their high temp stability oils in the 5000bhp gas turbines that I look after. Im also in charge of looking after our lube oil analysis for all our rotating equipment - but I will happily admit I know little about engine lube oils. Not enough to give detailed techinical advice anyway.

I think in answer to the question:
If you treat the car right in terms of warm up, change the oil as per schedule and use the right grade and quality - your engne is going to last a very long time, way over 100k miles IMO. As people have said, other things will wear, like cam chains, clutches etc but your engine "should" last.

End of????

MB

Turtle

VTEC killer cams are to reduce valvetrain mass and allow higher lift than the normal rocker ratio allows. Nothing to do with oiling.

Oil temps... depends on the oil.

Burning Mobil 1... all the Mobil 1 I've seen for sale on the highstreet in the UK has been an inappropriate viscosity for the F20C, so it's not surprising it doesn't allways work too well.

As to coatings, you don't want PTFE. More likely to use DLC variants. Coatings are used extensively in serious race engines. And in a lot of read engines too - there are some in the F20C.

-Brian.

Ultra_Nexus

I can understand the benefits of DLC on long term engines, and was aware of the carbon used in the liners of the F20C, but with a race car they get rebuilt every few thousand miles TOPS anyway. Unless the Mu, in combination with oil of course, is so small its negligible. *EDIT* Actually, I imagine the thermal co-efficient of expansion with DLC is quite low, giving a consistant tolerance at all temps. Just makes me curious, I wonder if they hone the cylinder bores differently (eg different angle) to account for high engine speeds?