152 Piston Ring Gap

[I Work on Cars]

I'm doing a complete overhaul on a 152 .040 over. I'm still waiting for my manual to show up but in the mean time I was hoping somebody could take a picture of the piston ring gap specs in their manual so I can get moving on this build! What are you guys setting these rings at? The engine is going to be bone stock and I was going to set the top ring at .016 but I'm not sure what to do on the second ring.

 

[Robert Kenney]

The standard for calculating the minimum recommended piston ring gap is the bore in inches X .0035 for normally aspirated engines. That shit goes out the window with turbocharges and any engine with power adders.
In your case stock bore 3.875 + .04 OS =3.915 x .0035= .0137 or .014 absolute minimum. Traditionally the 152 works very hard during it's life and should be given appropriate clearances in the top end. Going + .002-.004 on ring gap along with the proper indexing of the ring end gaps on the piston will take away nothing in the long run.

In the event that you would encounter over heating or detonation, you should go with your .016 on each compression ring. Butting ring ends can be catastrophic, and easily cause significant damage.

 

[I Work on Cars]

Thank you for the reply, I forgot to mention we live in Arizona so heat and detonation can be an issue out here. I ended up setting the gap to .016 and after I received the manual they give you a pretty large margin .010 to .020.