What do you think would happen?

[jrustles]

to a gasoline engine if it was filled with mineral SAE40, started up mid-winter (say -30C) and immediately pegged at redline?

What parts would see the highest strain?
Which part would be the first to fail/incur the most damage?

I have a vague idea, but I'm curious what others think

 

[Chris142]

Whatever parts are farthest from the oil pump would get the most wear. But it would not happen immediatly. Maybe if you did that every time it was started it would eventully die. Theres a cell phone station across the street from my work. When the power goes out the caterpillar diesel generators start up immediatly and go to whatever rpm(screaming) it takes to supply power to the cell tower. That cant be good for them but they keep doing it over and over,whenever the power goes out.

 

[Garak]

In certain Fords at least, you might have the distributor shaft twist off.

 

[Zaedock]

30*F below the typical pour point of a SAE40 - really? If you could actually crank it over, the rod bearings would take the brunt.

I don't think it would turn over though.

 

[turtlevette]

You'd have immediate "cavitation" right at the oil pump gears creating an air bubble and zero oil flow. The engine would probably last several minutes before seeing any damage since it's not under load. The bores would probably be the first to suffer with scuffing. If run long enough the lack of bore lubrication would cause the engine to seize. The bearings would have the first and maybe second layer melted away but they would not be seized.

And it would not be necessary to run it immediately to redline. Driving off in a normal manner would result in the same end.

 

[901Memphis]

Those cell phone tower generators should have pan heaters right?

 

[Realtech214]

To the OP, It would be fun to watch!

 

[Doog]

Originally Posted By: Realtech214
To the OP, It would be fun to watch!


Yeah from a distance...at -22F with a 40w it would crank really slow. If it did start at WOT you would probably blow the oil pump first or maybe throw a rod.

 

[Clevy]

Not really apples to apples but I've got 7 or 8 generators of various size and 16 5.5hp Honda 160cc gas powered air compressors in various platforms from inline twins,v-twins and a couple triples.
Those compressors are started in whatever morning temps all winter,usually no warmer that -30 and this winter was more commonly -35.
Once started they go full throttle,and to get them warm fast we open the drain cocks so the pumps have no resistance,making it easier on the engines to turn the pumps.
So they go from whatever ambient temp to full throttle instantly. I have 2 engines with in excess of 15000 hours and a few with over 10000 hours,and not one has ever had any work done other than fluid and plug changes.
I use mos2 every second oil change and conventional 5w-30 in the winter,15w-40 in the summer.
So under these extremely abusive conditions none of the motors burn oil. In fact fuel dilution is a bigger issue that oil consumption is.
Oil is changed ever 100 hours or every second Saturday,which is basically 100 hours.
So If running them like this was damaging it hasn't presented an issue yet,with my oldest engines being 8+ years old and more hours than I can count.
There are large generators onsite that have light stands that also run full throttle from a cold start and no issues to be mentioned.
Then there's the diesel machines that get maybe 5 minutes to warm up before they get hammered full throttle so if this type of operation wears them out I've yet to see it

 

[Merkava_4]

All the main bearings would spin out - all the rod bearings would spin out - all the cam bearings would spin out - all the wrist pins would spin out - all the cylinder walls would be deeply scored - and all the valve guides would be shot.

 

[SilverC6]

Hopefully this isn't an expensive piece of equipment we're talking about.

 

[Shannow]

While I'm well and truly on record as stating that the average punter in a temperate climate does not need VIs of 200, I am also on record as stating that this does not extend to hopelessly inappropriate oil choices....and SAE40 down those temperatures certainly is that.

a bit cheesy, but...

 

[JHZR2]

Originally Posted By: 901Memphis
Those cell phone tower generators should have pan heaters right?


They probably have batteries which let the engine come up and stabilize.

 

[jrustles]

Originally Posted By: Zaedock
I don't think it would turn over though.


Probably wouldn't you're right!



Originally Posted By: turtlevette
You'd have immediate "cavitation" right at the oil pump gears creating an air bubble and zero oil flow.


Wow, turt, you're actually right. You may now break out the solid-like syrup analogies, and you'd be right on point. Also, two kinds of cavitation, one happening inside the pump and one happening in the pan, considering the pickup tube would probably suck a nice crater which the rest of the pan oil could not refill under gravity alone.

Originally Posted By: Doog

Yeah from a distance...at -22F with a 40w it would crank really slow. If it did start at WOT you would probably blow the oil pump first or maybe throw a rod.


Yup, either of those could happen, easily. I've seen a crankshaft actually crack from a mid-winter startup and redline incident.

Originally Posted By: Merkava_4
All the main bearings would spin out - all the rod bearings would spin out - all the cam bearings would spin out - all the wrist pins would spin out - all the cylinder walls would be deeply scored - and all the valve guides would be shot.


All quite possible, with the main and rod bearings perhaps the first to see major damage. If any super waxy oil got on the cylinder liners, it could subject the ring pack to severe hydraulic forces (also depending on stroke length) caused by drag. Perhaps with a combination of the hydraulic forces and sudden temperature spike of the piston crown, cracked ring lands may ensue.

Originally Posted By: Shannow
a bit cheesy, but...



this video gets me every time!!

valid point though. At the time it was made, 0w30's were apparently "synthetic blends" according to the narrator.

Originally Posted By: SilverC6
Hopefully this isn't an expensive piece of equipment we're talking about.



Haha, noooooo, strictly hypothetical. I made this thread with the intention of facing our worst fears, and of course began with a super extreme scenario. I chose a gasoline engine example because they are not built as strong as diesels and have a considerably higher redline.


Now lets revise the scenario a little bit with the -30C days behind us, and with any oil well above it's pour point what would happen to the same engine is started up at 21C or 70F and pegged to redline with a modern synthetic 10w30, does anyone think the same risks and issues will present themself? (Bear in mind that this too is an extreme example as no self-respecting person is going to just start up their gas engine and peg it at it's redline.)

 

[Shannow]

For a single data point...
BJ B---in, the "Madman from Brindabella", had a Facon ute, with 302(Cleveland)/speed/9", that was prone to the occasional burnout, either after an evening at Rafferties, a film at the cinema, first thing in the morning...mostly on a stone cold engine, on 20W-50 ...coldest we got to was around -5C.

 

[jrustles]

Originally Posted By: Shannow
For a single data point...
BJ B---in, the "Madman from Brindabella", had a Facon ute, with 302(Cleveland)/speed/9", that was prone to the occasional burnout, either after an evening at Rafferties, a film at the cinema, first thing in the morning...mostly on a stone cold engine, on 20W-50 ...coldest we got to was around -5C.


Right on, I bet ol' boy is not a rare case either, on any continent!