How Long for Full Lubrication?

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if you are referring to startup from an overnight rest, it can take up to a minute for all the pressurized and non-pressurized areas to get oil.

This varies wildly from motor to motor by design
 
I would say immediately. Positive displacement pump and minimal volume of passages to traverse. With a vertically-mounted filter or properly working ADV, I'd assume the oil passages are filled/primed so that flow is instantaneous, even if pressure doesn't immediately shoot up.

Just thinking here, not stating facts.
 
There's always this picture, though it does not apply in the PI. (as this is at freezing)

Oil_time.jpg
 
I've started an OHC saturn without valve cover on a reasonably temperate day. I would call it "practically instantaneous". There is also a quite decent amount of random flow which would only be random X2 with the cover on .
 
There should be oil remaining at remote lube points - also, running at High Idle shouldnt pose too much stress on an engine. granted, Sub zero starts dont promote splash lube.
 
Sorry for not being clear on my question.

I was referring to start-ups after an overnight rest. I have a 3.0 liter diesel Toyota D4D engine. I'm currently using Mobil Delvac MX 15W40 (dino oil). I'm in a tropical country where it does not get cold so I think the W weight will not really matter.

For peace of mind, I was just wondering if I would need to let my vehicle idle for 1-2 minutes or if a few seconds would be enough to drive off already.
 
Originally Posted By: JBT
Sorry for not being clear on my question.

I was referring to start-ups after an overnight rest. I have a 3.0 liter diesel Toyota D4D engine. I'm currently using Mobil Delvac MX 15W40 (dino oil). I'm in a tropical country where it does not get cold so I think the W weight will not really matter.

For peace of mind, I was just wondering if I would need to let my vehicle idle for 1-2 minutes or if a few seconds would be enough to drive off already.


No need to idle at all.
 
Originally Posted By: SteveSRT8
if you are referring to startup from an overnight rest, it can take up to a minute for all the pressurized and non-pressurized areas to get oil.

This varies wildly from motor to motor by design

So are there any non-pressurized bearing surfaces in an engine? I guess parts of the valve train rely on some splash lubrication.
 
Originally Posted By: IndyIan
Originally Posted By: SteveSRT8
if you are referring to startup from an overnight rest, it can take up to a minute for all the pressurized and non-pressurized areas to get oil.

This varies wildly from motor to motor by design

So are there any non-pressurized bearing surfaces in an engine? I guess parts of the valve train rely on some splash lubrication.


I've never seen a bearing (plain that is) that was not pressure fed.

Depends on the engine design. Common motorcycle bottom ends are roller bearings, don't need too much oil. But many engines rely on splash to lube cylinder walls and valve gear.
 
Thanks for the inputs. So it would take about a minute or less (after a cold start) to achieve full lubrication.

My next question would be - Why is it recommended not to drive hard until the engine reaches its normal operating temp when all engine parts are already fully lubricated after about a minute from start-up?

The engine does sound different when I try to step a bit harder on a the accelerator on a cold engine. What causes this?
 
Since the engine has aluminum and steel parts in it which expand with heat different amounts. The engine parts are made so that they are the right size when at operating temperature, not when the engine is cold. So some bearings are loose, and the pistons are "loose" until the engine is hot.
 
Pistons are not round until they reach nominal operating temperature either. A four inch piston can be as much as 0.016 inch out of round. That's 4-5 times the normal operating clearance.

Ed
 
Wow! I've been wondering about this ever since I got a diesel vehicle (a few years now) and the "metal expansion/contraction when hot/cold" concept did not occur to me as a reason. I always thought the unusual engine sound when cold was due to lack of lubrication. Very enlightening. Thanks!
 
Most people feel when the OP gauge has reading that the engine is fully lubricated. While oil might be at all points of the engine at that time that doesn't mean it is doing its job to the best of its ability, and your engine is ready to be driven hard, or worked hard. Having oil pressure, and having an engine at normal operating temps with oil fully warmed up at the desired viscosity is a totally different story.
 
Originally Posted By: JBT
Wow! I've been wondering about this ever since I got a diesel vehicle (a few years now) and the "metal expansion/contraction when hot/cold" concept did not occur to me as a reason. I always thought the unusual engine sound when cold was due to lack of lubrication. Very enlightening. Thanks!


On a diesel, you'll have slightly advanced timing for a few minutes until it warms up.
 
Originally Posted By: IndyIan
Since the engine has aluminum and steel parts in it which expand with heat different amounts. The engine parts are made so that they are the right size when at operating temperature, not when the engine is cold. So some bearings are loose, and the pistons are "loose" until the engine is hot.


This is why I shudder when people tell me they remove thermostats from the cooling system.
 
Or maybe the unusual sound when cold is because engine temperature have something to do with combustion efficiency, not lubrication.
 
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