Oil efficacy

[vombil]

I recently did an engine oil change on LS3 and knew i'd left it a bit long (13,000). The colour was pretty brown for a 60,000 kms motor.
When a cold start mechanical noise it had with the old oil disappeared with fresh oil, it got me thinking about efficacy which lead me to a discussion I'd had with a mechanic about how terrible Harley Davidson oils were. He told me that by about 2000kms the warm/hot viscosity halves to what it should be. ie a 20/50 goes to a 2/25 because their oil just dies, or loses efficacy. Anyways - long way around, the same seems to have happened with me and my LS3 and dexos nulon 5/30. Moral of the story - pays to keep oil fresh because if you don't, it just stops 'working'.

 

[someguy360]

This is why it shits me to tears when people buy coles brand oil just because it's the right viscocity and do the whole "I'm not getting sucked into paying for a brand name".

Oils ain't oils,

I remember a couple from a while back that were industry tested at a 10w40 viscosity that after about 2 hours of high stress work would have the viscocity of water, and was bleeding off oil pressure.

I can't remember which names they were but they were a couple of the big ones.

 

[dassaur]

He told me that by about 2000kms the warm/hot viscosity halves to what it should be. ie a 20/50 goes to a 2/25 because their oil just dies, or loses efficacy.

This is patently untrue for a full synthetic unless it has become too hot.
Definitely oils break down, but a full synthetic will not break down that quickly.

 

[dassaur]

I remember a couple from a while back that were industry tested at a 10w40 viscosity that after about 2 hours of high stress work would have the viscocity of water, and was bleeding off oil pressure.

If this is the case and they were sold under the latest ACEA or API regulations that is very suspicious

 

[losh1971]

I think the general consensus on an LS is 7.5k oil change. I've been pushing it out to 10k for ease of remembering. I also figure when you have 8.5L in the engine you have bit more oil to contaminate before it goes to crud. Old V6 was 5k changes but only took just under 5L. I reckon once I get out on the strip and I intend to push the engine I will be changing the oil before I head out if it's reached 7,500 km.

 

[someguy360]

I think the general consensus on an LS is 7.5k oil change. I've been pushing it out to 10k for ease of remembering. I also figure when you have 8.5L in the engine you have bit more oil to contaminate before it goes to crud. Old V6 was 5k changes but only took just under 5L. I reckon once I get out on the strip and I intend to push the engine I will be changing the oil before I head out if it's reached 7,500 km.

As a general rule of thumb when I have a race meet I always dump the oil after the event.

Good way of checking that nothings been hurt during, and good insurance.

 

[Immortality]

As mentioned above, overheating the oil is the quickest way to kill it but conversely not getting the oil up to full operating temp is the most sure way to have it full of contaminants and turning to slush. So, mum doing the 5-10 minute school run and not getting the oil up to full temp is almost as bad as boy racer doing burnouts and cooking the oil

The best way to look after your oil is long drives that gets everything up to temp and allows the PCV system to evacuate those contaminants from the crank case.

 

[vr304]

As mentioned above, overheating the oil is the quickest way to kill it but conversely not getting the oil up to full operating temp is the most sure way to have it full of contaminants and turning to slush. So, mum doing the 5-10 minute school run and not getting the oil up to full temp is almost as bad as boy racer doing burnouts and cooking the oil

The best way to look after your oil is long drives that gets everything up to temp and allows the PCV system to evacuate those contaminants from the crank case.

That’s why I like to try (money dependant) and stick with 6 month oil change’s regardless of kms in my daily car as it does short trips on a regular basis

 

[Immortality]

My old VN was really bad for short trips to work and back and only 3 days a week. Not even enough run time to keep the battery charged over a long period so once a month I used to head up to the Bombay hills and back ( about an hour round trip) just to give it a good run and keep everything in good nic. Seemed to work, engine still looked nice and clean internally last time I checked it over.

 

[Ginger Beer]

5k km oil/filter changes in everything I own, I also give the beans to everything I own

Plus I enjoy servicing my vehicles myself

Supercharged LS1 (high volume Melling) = HPR5 5w 40, the car loves it, the engine has never been so quite on start up and idle

Harley 103 engine, primary chain case and gearbox i.e. 3 hole (engine has a Jagg air to oil cooler) = Penrite MC 4ST 20w 50 V twin, again, the bike loves it, and shifts are as smooth as silk

I was using the Screaming Eagle Synth 20w 50 when I first got the bike, but the Penrite V twin oil is just as good, and actually better for the shifts, plus the Penrite is also much cheaper