Box Stock

checking cc

J

jayo48

Member
when checking the cc, does the spark plug hole have to be level and plumb, or just level the head surface? i have a stand that makes the cylinder level and plumb, but was wondering if you have to level the tech nut to get the right reading?
 
The way I understand it the spark plug hole has to be plumb. Am I the only one that wants to see the cc rule go away?
 
The 2018 rule on pg 20, identify's that the center axis of the sparkplug hole is plum, cylinder head level
 
Last edited:
I thought everyone wanted to keep rule changes to a minimum.
Which it looks like has been done this year.
Congratulations on that.
 
I get that.
No cc I can see. With depth checks.
The piston and ring supporting itself seems reasonable to me.
In hindsight cc vs pulling the head
Cc is better
 
Last edited:
The language in the book for 2018 on pg 20 "cylinder head level" is a typo!! No change to the cc engine position has been made. Same as in the past, sparkplug plum
 
Will someone please enliten me on the cc process that keeps the air bubble from forming under the intake valve when setting the engine with the sparkplug plum. the intake side of the head becomes the highest point when the engine is set at this angle.thanks!
 
if you set your engine on a stand with the plug hole plum its very easy to see that the high point in the chamber is under the intake valve. when the engine is placed with the deck level front to rear the spark plug hole is at a perfect location to let the air escape therefore leading to a more precise cc check, the act of setting the spark plug hole plum comes from 2 cycle tech where the spark plug hole is in the center of the domed shape combustion chamber. spark plug hole plum does not work for our 4 cycle overhead valve engines. If I am wrong I need someone to tell how to eliminate the air bubble. I have set up engines with spark plug hole plum and then tilt the engine in such a way to relieve the air bubbleand made way for more fluid.
 
Set your engine with the deck level and fill with mmo to the top of the cc plug. Then imediately set the engine to the plug plum and see what happens.
 
Also do a cc check with the plug plum. Then roll the piston down and pull the head gently. If the head is wet in the area you are concerned about, and it will be, you don't have a bubble
 
You must log in or register to reply here.
Back
Top