CCing dished pistons

[Anonymous]

How can I figure out the cubic centimeters for a dished piston? This question is for my SBF build-up (yes Luke, join me...). They are for an '84 351W with .040 over stock pistons. The dish measures roughly 3" long by 2" wide and .19" deep.


-Chris

 

[66200i6]

Most accurate way is to use liquid, just like CC'n your head, if you really want an to end up with the same CC value in each cylinder. Just like each chamber will be different, each piston dish area will be different.

Have fun, Ric.

 

[CZLN6]

Howdy Chris:

An easy way is to get some modeling clay, press it into the dish of the piston and level the top with some sort of straight edge.

Now peal the clay out of the dish and drop the clay into a pre filled graduated becker. If the beaker is a 50 cc syringe, fill it about half full. once you've dropped in the clay note the before/after difference. That will be the volume of the dish. It is not necessary to maintain the shape of the clay once it is pulled from the piston dish. The volume displaced will not change with the shape.

The taller and narrower the becker the more accurate you will be able to be. I prefer a 50 cc dispossable Ag type syringe to a 1,000cc becker. I prefer to use auto trans fluid as my liquid mediam because of it's color. It is easier to see and has less surface tension then water. It is messier.

Adios, David

 

[Anonymous]

Perfect! Thanks David!


-Chris

 

[Anonymous]

If you do the clay method make sure there are no air bubbles in the clay or it will throw off your measurements. Also be sure to clean the pistons good afterwards to make sure there is no clay on them when you install them.

Dan

 

[Anonymous]

8) the way i use is to get a small container and measure the cc's(22/7 x raduis squared x )depth eg the container is 5cm in dia and 10cm deep.22/7 x 2.5 x2.5 x10=196.42cc's.pour in the liquid and then measure the remainder.remember to have the piston or head on a level bench(use a spirit level)after the remainder has been measuered subtract from the original.

 

[Anonymous]

OK SORT OF RELATED, I WANT TO C.C. MY HEAD WHAT KIND OF SYRINGE SHOULD I USE I CANT FIND ONE BIG ENOUGH

 

[addo]

Yeah, I am aware that some States have "issues" with selling syringes. Look for a place that sells WestSystems epoxy or other marine epoxies. They may well have syringes there - for some repair jobs they are almost essential. You want one that holds about 60cc (60 ml). They are about $10 here - that's $6.60 in your money.

If you make friends with a vet, you can get them a lot cheaper.

Cheers, Adam.

 

[Anonymous]

Yeah, I buy mine at the local feed supply store. In California it is legal to give required injections to your own pets and livestock, so you can just walk into any feed store and buy the syringes.

 

[CobraSix]

I bought a fuel/oil mixing "syringe" from wal-mart. It measured up to 100ccs I think.

Here is what I did:

http://kastang.tripod.com/ccing.html

Slade