View Single Post
Old 08-05-2016, 10:07 AM   #58
justatroll
Senior Member
 
justatroll's Avatar
 
Join Date: Dec 2015
Drives: Full race 4cyl boxer
Location: CO, USA
Posts: 587
Thanks: 310
Thanked 510 Times in 269 Posts
Mentioned: 20 Post(s)
Tagged: 1 Thread(s)
Quote:
Originally Posted by guybo View Post
No, I'm not. there's no way in hell that gasoline can hydrolock an engine with the starter only. It compresses enough that it can't cause a bent rod. Water won't compress at all and will bend a rod with the force of the starter motor though. Plus the injector would have to be pretty messed up to dump THAT MUCH fuel into the cylinder anyway.

Unpossible.
Gasoline is an incompressible fluid.

What defines the "compressibility" of a liquid is the Bulk Modulus.
This refers to how much pressure can a liquid withstand before 'yielding'.

The BM of water is: 3.12 psi, lbf/in2
The BM of SAE 30 oil is: 2.2 psi, lbf/in2
The BM of gasoline is: 1.9 psi, lbf/in2

So sure you could argue that gasoline is compressible only if you consider motor oil to also be compressible.
Are you going to argue that "there's no way in hell that motor oil can hydrolock an engine with the starter only"?

Just as a general rule: All liquids are incompressible (at least as far as the definition of 'compressible' goes).
However even water (considered to be Incompressible) will compress .024% at a pressure of 500kPa (or ~5 Atmospheres)


Now the fact is that all liquids are compressible to some extent, but water, oil & gasoline are definitely in the 'essentially incompressible' category.
__________________
Arguing with an engineer is like wrestling with a Pig in the mud. You are never going to win and after a couple of hours you realize that he likes it.
justatroll is offline   Reply With Quote
The Following 3 Users Say Thank You to justatroll For This Useful Post:
Brandond15 (08-05-2016), humfrz (08-05-2016), Icecreamtruk (08-05-2016)