Engine start up wear question.......

[demarpaint]

Originally Posted By: Gary Allan
Originally Posted By: demarpaint
Clear as mud!

Frank D

Yeah ...I get that a lot.

A friend kept telling me, "Simplify- simplify - simplify" ..but when I do that, then I get every other swinging member pointing out every over simplified nuance that exists under the sun.

..and people wonder why I have long posts

Well you and Doug H should keep those posts coming. I for one have learned a lot of the more technical things from you guys.

Frank D

 

[dbvettez061]

Some very interesting and complex answers, now i understand.....i think... maybe....

 

[Steve S]

Startup / warm up wear is not just an oil problem. There is a film of oil on the parts after the engine sits for quite a while .I have taken apart engines that have been sitting for several months. The articles been posted are usually not the best. The oil change increases wear article for example leaves out the fact that engines last the longest have had regular oil chages . Usually the most freeway miles or few warmup cycles per hour of use.

 

[Mamala Bay]

Originally Posted By: Steve S
Startup / warm up wear is not just an oil problem. There is a film of oil on the parts after the engine sits for quite a while .I have taken apart engines that have been sitting for several months. The articles been posted are usually not the best. The oil change increases wear article for example leaves out the fact that engines last the longest have had regular oil chages . Usually the most freeway miles or few warmup cycles per hour of use.


On the film of oil what oil tend to cling to the metal. Does viscosity matter or oil type?

 

[skoh]

Originally Posted By: Gary in Sandy Eggo

Automobile manufacturers are recommending lighter and lighter oils because they DO result in better mileage with adequate protection at sub-operating temperatures, because they know that most car trips never see full operating temperatures.



The Toyota Technical Service Bulleten (TSB) and the Owner's Manual both state that 5W-20 is OK. But, for better fuel economy & better cold starting performance use 0W-20.

Here is a link to download the TSB:
http://www.chrysanindustries.com/pdf..._tsb071002.pdf

 

[Iain]

Originally Posted By: Shannow
Two issues here, and an addition that I've never pulled apart a dry engine.

When the oil is cold, it's viscosity is high...very high compared to running temperature, and parts are quite physically separated. When the oil is hot, the additives provide much of the wear protection (bearings are still predominantly hydrodynamic).

It's the bit in the middle, as the oil thins, and before the additives kick in that really wears things out.

............


Don't forget that additives activate at various temperature ranges. Some activate at low temperatures whilst others activate at moderate or high temperatures.

 

[Steve S]

Also the clearances are different when the engine is cold and if you measure the pistons they are "Oval" and as the heat up tend to get "round" There is a richer mixture when the engine is cold and a bit more blow by etc.