Here is an inside view of the $300.00 + OEM EA82 SPFI Fuel pump. Nice little DC motor turns nice little roller pump. The whole thing, brushes, armature, and all, is in the gasoline! While there are only 2 of the 3 items needed to make fire, would you ever think of running a motor with a comutator in a combustible liquid?

 

Looks like the comutator is worn a bit, 180K miles or so, the pump had become intermittant to start running.

While there are only 2 of the 3 items needed to make fire, would you ever think of running a motor with a comutator in a combustible liquid?

 

No, I would not. But since liquid gasoline is NOT combustible, it's no problem at all. Gasoline vapor is highly combustible. In it's liquid form it's as safe as milk. If the tempurature is low enough, you can put a match out by dunking it in a bowl of gasoline.

 

GD

And the gasoline acts as a coolant to keep the motor from overheating and destroying itself.

No, I would not. But since liquid gasoline is NOT combustible, it's no problem at all. Gasoline vapor is highly combustible. In it's liquid form it's as safe as milk...

Not entirely true (but essentially so for normal situations). It has to do with temperature and not phase. Heat liquid gasoline up to above its flash point and introduce an oxidizer and it will readily combust. You touched on the "normal situation" aspect:

...If the tempurature is low enough, you can put a match out by dunking it in a bowl of gasoline.

 

GD

It isn't that the liquid phase is noncombustible, but rather that if its temperature is low then any minor heat source ("match") has its heat spread-out/dissipated too rapidly to provide enough energy to start combustion.

the fuel pump in my style of blazer tend to go out evrey 40-50000 miles if you let the tank run below 1/4 because they over heat

Yeah - that's the technical aspect of it. Thermodynamics and material sceinces aren't my major study areas. But the practical nature of it is that it's perfectly safe "in this situation"

 

GD

But the practical nature of it is that it's perfectly safe "in this situation"

 

GD

Agreed. Just didn't want some fool having a gas puddle on some hot part and think that it was safe to play with. (And maybe making the next Darwin Awards, with last words being, "GD said it was safe as milk..., so hold my beer and watch THIS!!! )

(And maybe making the next Darwin Awards, with last words being, "GD said it was safe as milk..., so hold my beer and watch THIS!!! )

there goes my darwin

I have an spfi sitting here and thought once about taking it apart (13 years and 161k). It was approaching intermittent, until i painted the exterior of pump and it went back to like new. Great photo- I wonder what a windshield wiper motor could do...

Just a decade has millions and millions of revolutions at 100k miles. The cold fuel no doubt is the pump saver.... keep those trunks lined, and wagons behind the seats, it saves the fuel pump in the shade

 

I took a liner out of my sedan trunk and the car ran differently, it changed the fuel pump- because it got warmer. warm fuel at pump is bad news unless it is new enough not to notice.

Q: What does actual pumping in photo, all I see is engine.

Q: What does actual pumping in photo, all I see is engine.

 

Above the screws there is a round part. The inner piece is turned by the motor shaft. It has slots that the 5 little rollers can move around in. They fly out, touching the inner surface of the ring shaped piece. The rotating center piece is not in the center of the ring, so the volume between rollers changes as they rotate artound the ring. There are ports that let the fluid in & out in the apropreate places.

Here is an inside view of the $300.00 + OEM EA82 SPFI Fuel pump. Nice little DC motor turns nice little roller pump. The whole thing, brushes, armature, and all, is in the gasoline! While there are only 2 of the 3 items needed to make fire, would you ever think of running a motor with a comutator in a combustible liquid?

 

Looks like the comutator is worn a bit, 180K miles or so, the pump had become intermittant to start running.

 

If you think thats scary, we wont even mention how the fuel sneder operates

 

nipper