Measure cubic inches

[It kix]

I have a guy that I am buying a car from and he told me that it has a 347 in it. Can I determine that without tearing down the motor? And if so how?
Thanks, Tony

 

[floyd4ford]

Nope maybe pull the pan if you can but probably have to pull it.

 

[It kix]

How does the NMRA and fun ford determine the cubic inches of the motors, is that by a complete tear down?

 

[bdcardinal]

supposedly in the higher NHRA levels they have a tool that can determine cubic inches based off of engine noise. also if someone has a larger motor it will generally be pretty obvious in a spec series.

 

[Zoie_daGT]

I dont know of a way that you can figure that out easy.

 

[SickBlackMach]

Tell him to get it dyno'd?
Does he not have a build sheet or shop number where it was done at?

 

[05 Roush]

Yes.

It's called the hydro test. Turn the motor to BDC (bottom dead center). Remove piston 1 spark plug. Fill the piston with gas using a beaker or measuring cup and a funnel. How much gas you put in before it overflows gives you 1/8 th the total displacement. Move the piston up to TDC(top dead center). Place a vacuum pump down into the cylinder and extract any extra fuel. Replace the spark plug. Fire up the engine.

It should take about 5-10 minutes to figure this out. Good luck. :thumbsup:

 

[thomas91169]

that would only work in a in-line configuration correct? where the plug is directly on top and the cylinders are at a perfect 90* angle.

how do you account for the fact once fuel starts spilling out of the plug hole the remainder of volume in the cylinder, since it is at a 45* angle and the plug hole is in the center of the cylinder? Follow?

 

[05 Roush]

that would only work in a in-line configuration correct? where the plug is directly on top and the cylinders are at a perfect 90* angle.

how do you account for the fact once fuel starts spilling out of the plug hole the remainder of volume in the cylinder, since it is at a 45* angle and the plug hole is in the center of the cylinder? Follow?

At BDC, piston 1 should be at the absolute bottom of the cylinder, regardless of the configuration. Fill it up and you have the maximum displacement of each cylinder.

Just make sure the cylinder you are measuring is at the very lowest point possible. It doesn't matter where the crankshaft is. I've seen mechanics use everything from metal rods to flashlights to figure this out.

 

[thomas91169]

i think this will explain what i was getting at, hard to say via interwebs!

 

[05 Roush]

At BDC, the intake valves are open and the exhaust valves are closed. When the valves are open there will be a minimal amount of liquid above the valve entrance, so you shouldn't have to worry about it all that much.

If you're really anal about the displacement you can get measurements for a standard valve diameter and use that to remove the total volume (at a 45 degree angle) for the intake side.

 

[CobraChris08]

Yes.

It's called the hydro test. Turn the motor to BDC (bottom dead center). Remove piston 1 spark plug. Fill the piston with gas using a beaker or measuring cup and a funnel. How much gas you put in before it overflows gives you 1/8 th the total displacement. Move the piston up to TDC(top dead center). Place a vacuum pump down into the cylinder and extract any extra fuel. Replace the spark plug. Fire up the engine.

It should take about 5-10 minutes to figure this out. Good luck. :thumbsup:

I think thats how they test motors for land speed records also.

 

[It kix]

Thanks guy great info.

 

[Juruense]

Isn't there also a formula, if you know the bore, stroke, etc?

Ask the guy to give you the numbers on bore, stroke, etc and run it through the algorithm if it does not match continue investigating before paying.

 

[Juruense]

http://albertstreetmiddle.nbed.nb.c...s_engines/Engine Displacement/Calculation.htm

 

[golden_eye]

Isn't there also a formula, if you know the bore, stroke, etc?

Ask the guy to give you the numbers on bore, stroke, etc and run it through the algorithm if it does not match continue investigating before paying.

That works but he wants to make sure the guy isn't lying to him about the internals. If he wasn't telling the truth he could just look up numbers and give those to the OP.

 

[Juruense]

Perhaps...

 

[swoosh_stang]

If it is a huge purchase for you, you shouldn't buy an engine without a build sheet, if you are considering it because it is a great deal you can take your chances.

 

[97WHITEVENOM]

If it is a 347, can you drop the pan and see if the block has been clearanced? It is not a guarantee that it is still a 347, but it may help.

 

[Got Boost?]

pay $50 to do a pull on the dyno. tell me the set-up and i can tell you if its a 347 lol. i dont know any ways to do it otherwise. however, im sure there are - such as the ones that are listed. i just dont know them personally.