indian chief ring end gap

[cscott]

would someone know the ring end gap on a 30 chief ,i read .010 to .020, seeing if people agree with this, also the side clearance of the piston to cylinder wall. thanks

[T. Cotten]

would someone know the ring end gap on a 30 chief ,i read .010 to .020, seeing if people agree with this, also the side clearance of the piston to cylinder wall. thanks

Please ask for a modern consensus, Chris,

For ring drag as well,

ringdrag.jpg

Since modern oil control rings, etc., complicate things I'm sure!

....Cotten

[otis71]

I can’t swear to know for your application but .010-.020 sounds correct. As far as piston clearances, it depends on if you are using cast or forged pistons.

[tfburke3]

I am usng the factory spec of .004 for a 38 chief I'm building with nos factory lynite pistons.
For Starks In my 80"I am running .006.
if I buy another set Iam going to try KIwis redesigned pistons ,and I would ask Mike for clearance spec.
I wouldn't run less than.005 in any repro piston,unless I had a reputable mfg. recommended spec.
Tom

[tomfiii]

Just google it and get the formula . No one hears about large end gap , but everybody knows when gap is too tight.

[dukekleman]

Cscott,

If you know your finished bore Size, use this formula for the "minimum" end gap of your piston rings.

Top Ring: Finished Bore Size X 0.004"
Example: 3.500" x 0.004" = 0.014" for a min. Top Ring Gap

Second Ring: Finished Bore Size X 0.0045"
Example: 3.500" x. 0.0045" = 0.016" ( Rounded) for a min. Second Ring Gap

Piston Clearance is based off multiple factors. I'm going to stress this, get the cylinder finish correct!!! This means
#1) The Cylinder bore "X" and "Y" axis parallel
#2) The RPK, RK and RVK numbers correct with the Honed finished cylinder wall.
If they are not correct, you'll be adding cylinder to piston skirt clearance for all the wrong reasons. Doing that as so many often do, creates a wave of issues.

I hope this helps,

Duke Kleman

[T. Cotten]

Cscott,

If you know your finished bore Size, use this formula for the "minimum" end gap of your piston rings.

Top Ring: Finished Bore Size X 0.004"
Example: 3.500" x 0.004" = 0.014" for a min. Top Ring Gap

Second Ring: Finished Bore Size X 0.0045"
Example: 3.500" x. 0.0045" = 0.016" ( Rounded) for a min. Second Ring Gap

Piston Clearance is based off multiple factors. I'm going to stress this, get the cylinder finish correct!!! This means
#1) The Cylinder bore "X" and "Y" axis parallel
#2) The RPK, RK and RVK numbers correct with the Honed finished cylinder wall.
If they are not correct, you'll be adding cylinder to piston skirt clearance for all the wrong reasons. Doing that as so many often do, creates a wave of issues.

I hope this helps,

Duke Kleman

I agree, Duke,

(Although I must again stress that all measurements should be taken while stressed.)

So any modern oil control rings should be ignored/disposed of?

Thanks in advance,

....Cotten

[tomfiii]

Oil ring is .015 minimum.

[T. Cotten]

Oil ring is .015 minimum.

Did '30 Chiefs have oil rings, Tom?

Askin' for a friend,

...Cotten