Ok, this may be common knowledge for some... but I thought I'd share.

I recently bought a set of heads milled to 57cc.
I was checking my PTV clearance when I unexpectedly had plenty of room.
Since the heads weren't bolted on yet, I wanted to make sure the heads were milled to my requested 57cc, so I did some searching.
I came across a couple of websites that sold a 'cc Combustion Chamber Kit'.
It consisted of a syringe type injection tool and a few pieces of clear plastic.

Well, I wasn't about to spend $20+ on $3 worth of items, so I looked around the house to see what I could find.

I came up with an eye dropper, a breast milk container, an old CD, some plumbers putty, and some silicone sealant.

Everything I had, measured in mL. The eye dropper went up to 5mL, and the breast milk container went up to like 80mL.
Lucky for me, 1mL = 1cc!!

So, I filled up the breast milk container to exactly 55mL, and then filled the eye dropper to the 5mL mark. The eye dropper will act as my 'fine tune' measurement to go from 55mL, to (hopefully) 57mL.

With that out of the way, I took a small amount of plumbers putty and blocked the spark plug hole (from the chamber side of the head). You dont need to stuff it in the hole, you just have to block it off and make it water tight.

The next thing I did was wipe a SMALL amount of silicone on the head surface that surrounded the combustion chamber. This will act as a seal for when I lay the CD on top of it. The CD will act as a cover. The hole in the CD will be the fill point. Get the picture?

So that's all I did. I put the CD on top of the chamber.... slowly poured every last drop of the 55mL through the CD hole.... and then slowly added drops of water from the eye dropper until I couldn't cram any more in, which was ~2mL. So the total cc of the heads were the requested 57cc.... so all is good!


Hopefully this will help somebody in the future. Its extremely simple and can really set your mind at ease after dropping some heavy coin on a set of heads.... or to check and see what you REALLY bought from a complete stranger.

Brian

 

I have witnessed quite a few heads being cc'd and everytime a sparkplug was used. So for others looking to see what compression ratio the motor really has I would use the spark plug that will be used in the motor.

Anyways pretty ingenious on your part.

 

Yep, spark plug should be installed since the plug will affect the chambers size. Without the plug installed your CC value will be a little higher than what it actually is when the engine is running.

I also use a slightly different method to check the CC but your way works OK too. Doing CC yourself is very simple.

 

Ha!
I knew it...
It was about 1/2 mL over the 57cc mark.

Thanks for the tip, guys!

 

There are 10ml child medicine oral syringes at most drugstores. I used that and an extra plexiglass sheet I had with some thread sealer. You can use a CD case you chop up since its clear if you don't have access to any plexiglass. Definitely use a Spark plug though.

 

First off, good write up and makes perfect sense.

Next, 57CC???? Wow that's pretty small. What's your compression ratio work out to? 12:1?

Just be careful with the tune and be aware of knock.

 

My 57cc heads, 2cc pistons, and .040 gaskets worked out in the 12:1 area. Knock was not an issue at all on my motor, I assume my tight quench area had something to do with that. I just pulled like 2 degrees in the initial tune.

 

Static Compression will be 11.80:1, and dynamic will be 8.56:1. We have 93 octane up by us as the 'high' grade.... I know a lot of other places only get 91.
I plan on being extremely cautious with the tune, anyways. I just hope I can still run a decent amount of timing without having a boat load of KR. My gaskets are .040 also.

 

I've always used plexiglass, but just my use your CD idea in a pinch.......never thought of that.

 

Yeah my numbers are close to yours and I even have ran 91 in it with no knock just to see how it would be, normally I run 93 though.

Remember that more spark does not = more power. If you have too much spark for your setup you will lose power. Max power comes when your burn is at the 14 degrees BTDC area. The best thing to do is real time tune the car on a load bearing dyno and mess with timing in real time while observing TQ readings. Hit max TQ and save that value and make sure you arent getting any spark knock.

 

LOL. Now that's being resourceful. I love it.