Oil breakdown

[Kas]

Recently, I change engine oil in my Hachi, blue Shell, 10W40, semisintetic.
Oil pressure was good, engine was running fine, no smoking for about 1200 km. In that period, I went to a trip, about 500 km, and push it between 5000 and 7000 rmp all the time, I enjoy a lot. In that period, engine didn't spend any drop of oil. Nothing!!!!

After that, I notice a little drop of oil pressure with hot, and cold engine.
Also, I noticed a little consumption of oil.

Is possible that oil breakdown after that ride in only 500 km?

Also, I noticed at my girl Honda Civic 1.5 VTEC engine big consumption of same oil, after change to Mobil, 10W40, same type, engine stop oil consumption.

[Mux213]

Kas,

Could it be because the engine has always run on mineral oil and now you switched to semi synthetic?

I've heard that this can cause problems because your seals and such are not used to the cleaner thinner semi synthetic oils and these oils can start sipping through or something like that...

Strangely enough i did have a similar experience once with shell oils, car suddenly started using more oil.

[James]

I think MUX is onto a winner here, the same thing happened to me and my mates Yamaha motorbikes, his bike went through ltrs of oil then he changed to mineral and it stoped using it, same as my bike.

Ive also been told Mineral Oil is better for older engines then semi or fully synthetic....don't know if that theroy is totally true.

[Mux213]

Well I have followed many threads about oil and the whole subject is simply confusing.

Its the switching from mineral oil to (semi) synthetic that makes it go wrong although not all semi synthetic oil is really that synthetic so it doesn't always go wrong...

From what I know its advisable only to switch after you do an engine rebuild and all oil seals and such have been replaced by new ones...

[James]

However many engine rebuilders say always run the engine in one Mineral Oil, once the engines done say over 1200kms you can then run it on semi or fully synthetic oil....I think it just comes down to who you talk to. I just run my engine on semi synthetic desgined for the age that the engine is...my cars done almost 200,000kms and I can rev it to red line and it doesnt blow any smoke or use any oil so maybe it comes down to how the engine has been treated prior to you owning it.

Its a strange one really.

[Mux213]

James, I've heard that too but thats only for the first 1000kms or so like you said. Thats not enough time for all the seals to be 'getting used to' mineral oils.

I'm not sure what the reason is though...

[Kas]

When I put this engine in my Hachi, engine was not running for 2 years.
First, I change to mineral oil, and drowe with mineral for about 1000 km.
Then I swiched to semisintetic Shell.

In first period, I didn't force to much, 5-5500 was the limit with hot engine.

Engine has no leaking at all, everything look's normal.

I know that when swiched to semisintetic or fuul sintetic engin can start eatig oil, BUT, can minerail oil be good for engine which rews to 7-8000 rmp?
I know that engine is old design, but, I also know that engine is very strong and she need a good lubricant.

I think if I use mineral oil, my bearings will break like shit.

In first time, Zax use 0W40 oil, than he change to semisintetic, 10W40.
As you all know, his bearings are broken. Yes, he drive like maniac, reving sometimes above 8000, near about 8500 what is a WAY to much for semisintetic 10W40 oil.

THIS is my opinion, and I will try now with full sintetic 5W40 Mobil.

[Denmark]

I use Castrol RS 10W-60,and that is the only oil i trust to work,when driving at high revs,but also,becourse the temps are high with a turbo engine.


When i break in a engine i always uses mineral oil,for 500km,then change to another batch of the same mineral oil,500km,

Then Castrol RS 10w-60,and ofcourse change the oilfilter every time

Skassa

[jamiemirror]

If you change oil frequently - the mineral one will work fine. About consumption - this is mechanical problem. Change rings, valve stem rubbers, gaskets - and then you will not get problems with oil consumption.
If you drive hard - the engine will consume more oil - mineral, synthetic - no matter. If you use incorrect viscosity oil - the engine may failure (if the upper viscosity number is too low). If the oil is too old - the engine will failure too (mineral oil lose lubrication characteristics earlier than synthetic one). If the oil is too hot - the engine will failure too.
So, this is complex. If you drive moderate, change oil frequently and use adequate viscosity - no problem even with mineral oils with no oil consumption overall. They can use either synthetic oils - no problem. Sport style drivers must use bigger oil cooler, use more expensive synthetic oils (which lose lubrication characteristics slower than mineral oils) and keep an eye on oil level - they may have increased oil consumption due to driving style (at least).

Just my 2c.

[Kas]

jamiemirror Wrote:If you change oil frequently - the mineral one will work fine. About consumption - this is mechanical problem. Change rings, valve stem rubbers, gaskets - and then you will not get problems with oil consumption.
If you drive hard - the engine will consume more oil - mineral, synthetic - no matter. If you use incorrect viscosity oil - the engine may failure (if the upper viscosity number is too low). If the oil is too old - the engine will failure too (mineral oil lose lubrication characteristics earlier than synthetic one). If the oil is too hot - the engine will failure too.
So, this is complex. If you drive moderate, change oil frequently and use adequate viscosity - no problem even with mineral oils with no oil consumption overall. They can use either synthetic oils - no problem. Sport style drivers must use bigger oil cooler, use more expensive synthetic oils (which lose lubrication characteristics slower than mineral oils) and keep an eye on oil level - they may have increased oil consumption due to driving style (at least).

Just my 2c.

Which oil do you use?

I was thinking about Castrol 10W60, but it is too expensive, here, 4 liters, about 60 €.
If you change every 7000 km, thats twice a year for me + maybe something extra........ Too much.