Fastest way to determine cubic inches:

What's the fastest way to determine cubic inches?

Note: the scenario is 250 cars showing up at an event and we're not doing any of that bracket racing shit.

Shoot.

 

Huh?
Bore and stroke calculation is the only way.

 

Google the formula. There is no "fastest way".
Uh, 250 cars? Okee-Dokee. Look forward to the after event report...with photos.

 

i mean without taking the engine apart---hopefully.

 

If I told you its 383 or 302 you could not tell .
Unless you took it at least some what apart.

Number will tell you what it was originally most of the time

 

look at how they do it at bonneville.

or this?

http://www.speedtalk.com/forum/viewtopic.php?t=1237

 

On the Salt they blow from a spark plug hole into a measured chamber. You must pull the rockers on the cylinder being checked. So it won't work on flatheads and most DOHC engines

 

As Rich said, if you measure the volume of one cylinder, it can be multiplied the number of cylinders to give displacement. Valves have to be closed, on std OHV with rocker arms you just back them off. Other wise you are looking at pulling a head off to measure bore and stroke (at least accurately)

 

Does your question indicate that cars will be paired, or grouped, on cubic inches only?

 

There's a device called a P&G or something like that they use all the time on completely assembled engines. It's very accurate. The NASCAR guys know all about them.

 

Damn, what you got against brackets? You must not be able to drive.

Nothing more fair and true than RACING brackets. The car and driver running their dial-in no matter how fast.

 

Ask the driver.

 

Also never heard of PRE-RACE teardown. The cheaters win in your senerio anyway to cubic inches because they have altered other things to give advantage.

 

Pump gauge would be your best bet. That katech "Whistler" thing sucks ass! I know a guy who's an engine builder buy trade and a former WISSOTA tech inspector, i don't know exactly how it works but he said they pump a measured amount of air into each cylinder. But it has to do with how well your rings seal is. alot of guys use a leak down tester to find out which cylinder has the worst seal and have the tech guy pump that one.

 

Must have the tech guy in their back pocket. Most tech guys I've seen in action TELL you what cylinder they will check.

 

Bore X bore X stroke X .7854 X 8(cylinders)= DUH???

 

fill the cylinder with a liquid and then you see how much it will hold ,tham X 4 /6/8 /12 and may 16 lol

 

This, but there not cheap. You remove ALL spark plugs and one cylinders rockers or pushrods to use.

Remember it's easy if it's a small block Chevrolet...................it's always from a Corvette.

 

BTW, they cost around a grand so maybe think about a plan B unless you know someone who already has one.

 

I've had NASCAR puff my motors after races at a couple of tracks. There was no discussion regarding a specific hole, they said to back off the valves in one cylinder, let it cool down to a certain temperature and call them back to do nthe test.

We just made it easy on the ourselves. The #1 is the easiest to reach and convenient for setting the valves back up once the test was done. Of course if you were running 7 cylinders over-size and left one standard, you'd leave #1 as the odd one.

Bob

 

I have a Speedway Cubic inch tester for sale, $400 in the wooden box, complete, PM me if interested

 

Swept volumn. You can get a tool from a rtool supplier like snap on or, you plug it into a spark plug hole and have them turn it over, swept volumn and cubic inch displacement are the same thing.

That is how most sanctioning bodies do it any more.

Or you could make a protest charge, if someone thinks that someone else has a cubic horse power advantage they pay X dollars to pull a head or 2X dollars to pull both. If it turns out that the fella was cheating the money goes back to the protester and if not the fella who pulled the head gets the cash.

It cures both parties from sucking eggs, no one wants to pull a head for free and no one wants to loose the money in the first place.

When I was real little it was a hundred bucks a head.

The Ol' man was tunning a modified sports car for a fella and this corvette kept just smokin' him. The vette sounded funny, they protested 3 times the first two times the guy pulled the same head it was his choice, the last time the ol' man came up with enough to get both heads pulled, he had one side of his engine overbored. The guy had a choice give back all the purses plus all the protest money or get black balled.

 

Ya got a local circle track near by? Most of them have the equipment to check cubic inches. Maybe you could hire their tech guy for a day or rent the equipment.

 

Most of c-10's posts are hypothetical but do get a lot of comments. If I see one of his I get ready for the show!

 

Did you read the question? He didn't ask for a mathematical formula. How do you suggest getting bore and stroke measurements for 250 cars in the pits?

 

Whistler is for checking CR, not displacement.

 

I'd talk to the mechanic instead.

 

Do it the old fashion way. Honesty. Put everyone down on what they say it is and let everyone race. At the end of the races the winner can be challenged on his claim. Either prove your cubic inch or give up the trophy. Let the problem be the winners !!

Old dirt track trick or rule. Put up cash to see the teardown. If you were second, and it is what it is, ....now you still finished second and lost $500...smiles

 

Depending on how many racers might be bumped up a class, you could look up the casting number on the block and assume that the engine has maximum stroke and bore. Not completely accurate, but attends to the "no replacement for displacement" mindset, and is quick and free.

 

Ask the driver is the best answer? Gee.....I can't imagine any car driver lying about such a thing...