psi???

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how does psi work out? like if someone says that they are pushing 10 psi's. what does that mean? what does psi mean?

posted by  silvia_star

psi stands for pounds per square inch

posted by  google.com

its pressure

posted by  mazda6man

idiot...and i make myself look bad... :doh: :orglaugh:

posted by  rsxdude

http://auto.howstuffworks.com/turbo.htm

posted by  importluva

oops my bad i thought it was pounds not pressure

posted by  google.com

He was asking a simple question. Not everybody know as much as you "think" you do

posted by  99integra

it is pounds per square inch...

posted by  dodger65

he meant pressure as in thats what PSI is, not what it stands for. the definition for PSI was correct...

posted by  dodgerforlife

oic...

posted by  dodger65

that was directed at google/mazda6man, not at you :orglaugh:

posted by  dodgerforlife

It means atmosphere pressure (14.7 pounds of pressure) PLUS 10 more pounds of pressure from the turbo or supercharger idiot.

posted by  CarEXPERT

You have no room calling anyone an idiot, and he was asking a simple question :banghead:

posted by  99integra

Yes thats why I called him an idiot.

Alright I have a question for you. For radiators, is the coolant only under pressure when it heats up? And what drives the oil pump?

posted by  CarEXPERT

Yes the coolent is only under pressure when it heats up, how do you think people change it without it blowing up in they're face.

The oil pump is driven off the camshaft.

Answer your question or were you trying to make me look like an idiot

posted by  99integra

No, I just wasnt sure. Alright as for the oil pump, it is driven off of the camshalft with a driveshaft right? But isnt the oil pump in the oil pan? And the distributor is also driven off of a gear on the camshaft.
Some oil pumps are also drvin off of the crankshaft. Doesnt the one driven off the cam go more slower so less oil pressure?

posted by  CarEXPERT

Yes the oil pump depending on the car is in the oil pan
And not neccesarily, the cam is always running even at idle so there won't be a big drop in oil pressure.
Then again someone correct me if I'm wrong

posted by  99integra

Where is the ignition distributor for a Longitutal engine(RWD)?
I know its on the rear next to the firewall but how is it connected? Is it vertically or horizontally like a honda? And is it conncected to the cam also?

posted by  CarEXPERT

Help!

posted by  CarEXPERT

I said help

posted by  CarEXPERT

Dude chill out, not everybody is on 24/7.
Wait for someone like ChrisV or Banff to fully explain it

posted by  99integra

Holy, you gotta be patient like everyone else. You cant expect and answer to your question right away.

posted by  car_crazy89

How does a topic that starts out as a simple psi question end up being about oil pumps and dizzys?

I must admit I can't say as I've seen a dizzy against a firewall on a log engine.

posted by  Wally

Wally, how is the dizzy usually connected on a log engine? I usually see it sitting vertically as opposed to transverse engines. But I wonder how is it driven off of the camshaft like that.

posted by  CarEXPERT

Here's an old ford six that should answer you queries:

http://www.geocities.com/edwins63/223I6.jpg

posted by  Wally

wally nice picture.

posted by  CarEXPERT

Wally, in my auto book it says this.

"the oil pump usually has a drive shaft that is driven by a gear on the camshaft, although some pumps are driven by the crank. Pumps that are driven by the cam gear are usually connected to the bottom of the distributor by a driveshaft. On the bottom of most distributors, there is a gear that meshes with the gear on the camshaft."

Is that what your picture is? But that is not modern engine, and How does it work on transverse engines?

posted by  CarEXPERT

And wally thats a pushrod engine. How is it on a Honda? On hondas, the dizzy is horizontally on the cylinder head coneected to the cam. Im talking about OVERHEADCAMS engines. Is it driven off of the crank on a honda?

posted by  CarEXPERT

Yes the six shown has a drive shaft form the dizzy to the pump. Even the later models such as 5.0 litre Ford V8's inherited the same method, mainly because the block barely changed for several decades.

DOHC Jap engines tended to have the dizzy connected to the end of one of the cams for direct drive, rather than using a gear drive/pinion setup.

And yes there are many Jap engines that have a sprocket on the crankshaft that accepts a chain drive to the oil pump sprocket.

posted by  Wally

And Wally, I was reading the other day and on log engines, the upper radiator hose is where the coolant exits the head and the lower is where it goes back to the pump. Also the thermostat is on the upper hose.

But what about transverse like a Honda, is it the opposite because the water pump is on the side. How does the hoses go to the pump?

posted by  CarEXPERT

For various reasons the water generally exits the head to the top of the radiator. The cooler denser water at the bottom of the radiator is drawn back into the pump. Some motors have a steel pipe that runs under the exhaust manifold to the pump intake.

If the pump was to draw from the top of the radiator, there could be problems in the event of partial water loss, vapour plugs, etc. A water pump always performs better with a good positive suction head afforded by a water column, thus avoiding cavitation.

posted by  Wally

Opps sorry thats not what I ment.
I ment, on transverse engines like Hondas, how does the coolant flow cause the pump is on the side. Does it flow from the bottom hose to the rad to the upper hose then to the head on a TRaNSVERSE enigne?

posted by  CarEXPERT

I thought I answered that.

On a tranverse engine the pump is still at the front of the engine. although facing a wheel arch. The water flow should still be from the bottom of the radiator to the pump. The pump circulates the water through the engine, the water exiting the head (via the thermostat) and entering the top of the radiator.

If the designer had the water pump drawing from the top of the radiator he would be foolhardy.

posted by  Wally

So you are saying that log engines and transverse engines flow the same way? How come on a Honda, when I follow the bottom hose, it goes back near the bottom of the intake manifold where there is a thermostat housing and it is where it is connected to the block. And the water pump is on the drivers side of the engine because thats where the belts are.

http://www.cardomain.com/ride/695712
Go to this and look at the second picture and tell me if you see the thermostat housing on the cylinder head.

posted by  CarEXPERT

Well seeing as you asked I would say that certainly looks like a thermostat housing connected to the pipe going to the top of the radiator.

Maybe this will help
http://www.partstrain.com/ShopByDepartment/Radiator/HONDA

posted by  Wally

It doesnt say how the coolant flows. I'm talking about which way it flows. Im only intrested in Transverse engines so remember I know the how the Log engine system works.

Wally listen to this, on a transverse engine,Hondas, the water pump is usually on the drivers side of the hood(right side looking in) and the BOTTOM radiator hose leads to the other side into the block. The lower hose isnt connected to the water pump like in Log engines.

posted by  CarEXPERT

Physically I don't know where the water spigots are on your generic Honda engine. Maybe the water return has a tunnel inside the engine to get to the pump intake?

I really don't want to investigate the mechanics of the process for you. That is better dealt with by a Honda enthuisist, of which I'm sure there are a few here.

posted by  Wally

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