Need help with rebuild using CP pistons (SC7200) & rings

[TOMSUN]

Guys how ya been... I haven't been on here for a while...
Moved house, new job and had another son born 6 weeks ago.

Trying to get back into the rebuild...
Progress so far...



Also the pistons have a valve reliefs cut further over and into the side of the piston on one side which I assumed to be the exhaust side. BUT on the paperwork it has:
intake valve relief -0.16
exhaust valve relief -0.130
Are the saying the intake relief is the deeper side?
Which way do the they go?

Problem, I have been supplied 2 different Ring sets with my CP pistons.
Which ones are the right rings to use?
A



or B



Note: On the packaging the have a part number RS1616-3366-0
:beer Pete

[iXNAY]

i beleive A is the correct oil ring but wait for someone with more experience to answer!

[flav]

Hi Pete!
Firstly...and mostly(as u are by now well aware) congrats on the new bubbiee. Nothing in the world can bring you happiness like a bub.

The rings are dependant on your gaps. By the looks of it your using 2x2x4 or and this will lead you to use version 'A' as the oil ring, if you have been given 2 oil ring sizes.(with the supports on top and bottom of that ring.) Dont do this if you have not done it before. You will have a chrome molly top ring which will snap if you bend it a tiny bit too far.
You have deeper inlet releifs which is common and that will obviously tell you that this side is the 'Intake side'. ..OR..if you like, the notches on the big end caps (which go notch to notch on rod and cap) is ALWAYS the exhaust side.(you can see the notches in pic 3) So....looking at your engine from the front and deck (or top)facing upwards you are punching your pistons in (with a high quality ring compressor fitted and always square to the deck) with the larger releif to the right of you and the notch to the left.
Any more info needed just let me know...or just send yr pistons, rings & rods over and i will fit it up free.

[Sigma_turbzz]

Ummm deeper valve relief is usually exhuast side??? The inlet valve is much bigger then the exhaust valve so c if they cut the valve reliefs a diff diameter ??

[TOMSUN]

Thanks for the help guys...

The second ring is thicker than the top ring... probably not 2x2x4?



A BIT MORE INFO...

There was 4 plastic bags with a top, second and 3 -piece oil ring.
3 bags were the same. 1 bag had a different top, second and 3 -piece oil ring.

I went back the the shop and he gave me 4 new ring sets (but they were the same as the odd one out... so that is like saying I got 1 right ring set and 3 wrong sets with the original batch... ? Sounds odd to me.

I hope he didn't give me an inferrior type of ring set...?

I the meantime... I have emailed CP (usa) just to clarify...


And thanks for the very generous offer Flav, but I want to have a go myself. (But I'm not worried about putting my hand up for help from time to time) :beer


PS: What gaps would you recommend for For street (15psi) and strip (25psi) use?
Top ring:
Second ring:
Oil ring:

[TOMSUN]

A response from CP

****************
Set B is the correct rings.

We changed over rings 2-3 years ago because of availability; there is nothing wrong with Set A.

I recommend .019” on the top, .025” on the second.
****************

Cool... I can continue with the rebuild :D

Next.. ring gaps???

That seems like a big gap for the second ring.
I might go .019” on the top, .022” on the second.

[flav]

I used to run .022 top and mid on the blown 350 race engines, i tried smaller gaps at times but ended up with rings binding. If your going to race i would go the wider measurment but if its a streeter with an occasional blast then .020 would do me. See what the ring company reccommends, it should be on the spec sheet that comes with the rings.