Engine idles rough, sputters bad when throttle opened up

[doofus]

Take Christophe's advice and check ring end gap. if you break one ask your FLAPS for a single piston ring set for a 194 chev "6".that will save the bewildered look on the counter guy's face when you say Studebaker. Luck Doofus

[christophe]

Just to be on the safe side, removing (or installing) piston rings calls for a special tool if you don't want to harm anything. Sometimes, this can be done by hand but difficult to do without harming the piston. Also, the end gaps positions must be respected.

[jostanton1]

Well what do you know, I went to remove a ring from the piston (out of the weak cylinder) to check ring gap. When I opened the ring expander, the top compression ring split open! It had a hairline break I did not see when I inspected the piston! I hope a new set of rings will give me the compression I should expect. I'm also installing the thin shim head gaskets. Fingers crossed.

[christophe]

It seems you nailed it. As a fractured ring can't deliver the proper tension, it can't hold the pressure (especially the compression ring). If a Professional did this job, I would then ask for a sizeable refund. It looks like the ring was installed by expanding its two ends without the proper tool. Now, the bad news (sorry!). I sincerely hope for you this was the only ring subjected to this kind of treatment...
Nice day to all.

[jostanton1]

Started the motor up yesterday and she purrs like a kitten! Compression check yielded about 130 psi average with the thin shim head gaskets. Thanks to all on the forum who gave me good advice. This was an expensive learning experience. And BTW, I was the dummy who installed the rings the first time without a ring expander! I'll never do that again!

[TWChamp]

Yep, a ring expander to install rings on the piston is the best way.
Also need to use care when using a ring compressor to install pistons. I've seen the oil ring slip one rail out of the compressor before it enters the cylinder, and it also happened to me, but I worked slow and caught it before the ring was damaged, or the piston ring land was cracked.

[christophe]

Glad for you the troubles are over. Enjoy your car, now. Don't forget you'll have to change oil and filter after a few hundred miles.
Nice day to all.