R34 oil and timing belt change

[drifter17a]

Have a forged r34 using 10w60 mobile 1 running around 700 mark fly. 
 

i only used it 200 miles since last march when oil and filter was done. Now I will be using it more often and set to change oil and throw away what I had opened from last year.

 

Question is, does oil setting on shelf for a year or so breakdown or even few years?

 

how about sitting in engine?

 

engine rebuild will be a lot more costly hence why I change it every 12 month and wanted to get some opinion

 

question 2 is around timing belt, was done 4 years or maybe 5 years ago and since car done less than 1.5k miles. Would you change it ?

[luke gtr]

All comes down to recommendations and how much you have.

If you have the money, both are a great piece of mind to be done. And I believe most people would tell you to do them.

Any fuel sitting in the oil may have caused degradation.  Personally,  I have reused a timing belt after sitting for 2 years whilst getting a rebuild. Didn't have any issues.

Id probably dump the oil, fill with fresh, and get on your way.

But, keep in mind, I'm just some guy on the internet. 

[GTSBoy]

But don't throw away the unused oil in the opened bottle. That's just daft.

[drifter17a]

If it sits on shelf opened then it is no good and I don’t have a use for it really hence why throw away. 

[GTSBoy]

7 hours ago, drifter17a said:

If it sits on shelf opened then it is no good

Would you care to explain the logic behind that statement?

[drifter17a]

38 minutes ago, GTSBoy said:

Would you care to explain the logic behind that statement?

My understanding is if oil sits and exposed to air/ not sealed, molecules break down etc / could be wrong

[GTSBoy]

Yeah, it's bullshit.

[joshuaho96]

2 hours ago, drifter17a said:

My understanding is if oil sits and exposed to air/ not sealed, molecules break down etc / could be wrong

Theoretically maybe, but if you capped it tightly it's fine. 

[GTSBoy]

I'd say if you put the cap on loosely and left it there for, say, 10 years, it would still be fine.

[Dose Pipe Sutututu]

17 hours ago, drifter17a said:

throw away what I had opened from last year.

Wow.. I literally just refreshed my oil with oil from a 20L mini drum that's probably about 5 years old.

It will get a thrashing in a couple of weeks on the track too.

But hey sure, if you want to discard new oil, thwn go for it.

[Kinkstaah]

As someone who has had a car sitting for a year... would you change *that* oil?

It's still sitting in a container, right? If oil is fine in a shelf, is it not fine in a sump?
I assume this is something specific to the oil being *unused* (i.e on shelf)

[The Bogan]

2 minutes ago, Kinkstaah said:

As someone who has had a car sitting for a year... would you change *that* oil?

It's still sitting in a container, right? If oil is fine in a shelf, is it not fine in a sump?
I assume this is something specific to the oil being *unused* (i.e on shelf)

I would, especially if the car has had a few start ups or short trips to move it around 

But then I'm anal as fark about oil changes, as oil is cheap, and servicing is fun.....

[MBS206]

6 hours ago, Kinkstaah said:

As someone who has had a car sitting for a year... would you change *that* oil?

It's still sitting in a container, right? If oil is fine in a shelf, is it not fine in a sump?
I assume this is something specific to the oil being *unused* (i.e on shelf)

My answer would be, that depends.

If it's something that can be grumpy to start, runs a bit rich, and is likely an expensive engine, then yes, I would. But there's a few reasons why.

Sumps aren't really sealed, there is airways to them, so it is technically open to moisture. Secondly, if as mentioned it has been started, and it's a fuelled up, I'd dump it, as chances are, fuel is in the oil.

Next to that comes, how much use had said oil seen before it was parked up. IE, how much carbon, and potentially fuel/water did get in there while it was being used, and has now been allowed to sit, and slowly come together?

For the most part, if it's just been something like a road car, stock engine, nothing wild, f**king send it if it's not near oil change spec.

[Duncan]

For the oil on the shelf.....just consider how long it sat around between when a dinosaur wee'd it out to being put in a container

There are fluids that don't keep, unsealed brake fluid in particular is no good within about 12 months, and regular unleaded starts to go bad (gummy, particularly in small carburetted engines) within 3 months, but oils are fine

[silviaz]

On 11/22/2024 at 8:44 AM, GTSBoy said:

Would you care to explain the logic behind that statement?

I have 2 year+ new oil that I've been collecting (left over oil from oil changes) fully synethic, I was gonna use as back up oil. Apparently the oil breaks down after a while, loses its properties but I haven't looked extensively into it. Otherwise would put the entire bottle in my engine.

Edited Saturday at 08:16 AM by silviaz

[GTSBoy]

Take it from a Chemical Engineer. It will be just fine.

[joshuaho96]

1 hour ago, silviaz said:

I have 2 year+ new oil that I've been collecting (left over oil from oil changes) fully synethic, I was gonna use as back up oil. Apparently the oil breaks down after a while, loses its properties but I haven't looked extensively into it. Otherwise would put the entire bottle in my engine.

It is fine. The bigger issue is people not being careful with their oil between breaking the seal and actually using it. I have seen literal pebbles of asphalt fall out of "clean oil" bottles. Always take great pains to avoid dropping the plastic foil bits into the oil. Try to avoid putting anything dirty into a "clean bottle" like vinyl hoses, etc. I pour my oil into a syringe, then cap it, then inject into the diff/transmission/etc instead of sucking it up with the hose now. I never drain "clean oil" from an engine and try to reuse it. List goes on. Don't care how clean it looks, the moment it goes into an engine even if it looks brand new I am not going to risk foreign debris getting into something.

[GTSBoy]

Bah. You could literally throw a handful of gravel into the sump with the fresh oil and that is where it will stay. Screen on pump inlet, filter on pump outlet. No grit is getting to the rubby bits.

Not saying to try it, but paranoia is unjustified.

[joshuaho96]

20 hours ago, GTSBoy said:

Bah. You could literally throw a handful of gravel into the sump with the fresh oil and that is where it will stay. Screen on pump inlet, filter on pump outlet. No grit is getting to the rubby bits.

Not saying to try it, but paranoia is unjustified.

I have seen enough fire and brimstone from TSBs about roloc disks causing spun bearings that foreign object contamination is top of mind for me. For sufficiently large particles you might be right but usually it’s a distribution of debris and some of the larger particles can also break down and shed bits. If local shops report RTV contamination in a turbo is enough to wreck them I’m taking zero chances if I can help it.

[GTSBoy]

Yeah, there's a bit of a density and friability difference between pebbles and any of those other things. Silicone will definitely float in oil and so will be mobile enough to move around. Although, again, if it is upstream of the filter it really shouldn't go any further. I would only ever worry about silicone when it is in places downstream of the filter. Upstream of the pickup is a whole 'nother matter. We've all seen what that does.

I have seen the most abominable crap settled out in industrial gearboxes, trunnion lube systems and the like, without any sign that any of it has touched anything in the machine. Just chilling in the bottom, waiting for the inevitable operator error that causes the whole machine to need to be dismantled for repairs.