Hey guys. Everyone is talking about opening the ring gap to .028. Could this hurt anything? Aren't they just relieving cylinder pressure by pushing it past the rings? Ive seen quite a few people use gapless rings once they go forged which would be the opposite of what people are doing with the stock motors. I can understand why it would help with boost but how much longevity are you sacrificing? Anyone done this and noticed any issues?

 

I have done it, no issues but I ran a vacumm pump style pvc on my turbo car.

 

I'm pretty sure that people do that, because under boost the ring gaps get forced closed thus causing piston ringlands to break. I'm sure someone can explain it better than that if I am even correct.

 

You should consult with the ring manufacturer or an experienced engine builder for real world results. From what I have seen I would suggest .0065" x bore for the top ring and slightly larger on the second for a boosted application.

Top ring .0024-.0028
Second ring .0026-.0030

 

It's not necessarily a boost issue, but rather a power/heat issue. As you make more power, you produce more heat. As the rings heat up, they will naturally expand. The hotter they get, the more they expand. If the ring gap is too narrow and the rings get hot enough, they will eventually touch. If they touch and then still get hotter, they are going to expand even more. However, they now have no place else to go. Now they are going to start pushing up or down into the ring lands. This is why ring lands crack and break. Again, not just a boost issue, but in reality... a heat issue.

Gapless rings are not conventional rings. They slide over one another. When they heat up, they don't touch end to end. The top just slides over the bottom.

The majority of your blow by typically does not come from your ring gap. It comes from your cylinder being out of round (Not a 100% perfect circle). This is why they make exhaust ports in race pistons. It takes cylinder pressure from the combustion process and forces that pressure to the back side of the piston rings. This in turn forces the rings into the cylinder walls creating a much better seal. You do sacrifice engine life though. But that is for race apps anyways...

Over all, you should not be opening up to a generic .028" ring gap dimension, but actually figuring out what your gap should be for your type of power application via the appropriate formula. This comes from your bore size. Not everyone has the same bore size. Therefore, not everyone will have the same ring gap.

To the above post. .0065" x bore would be on the larger side of the correct area (I would say .006"). Also, the bottom ring gap should be 20-30% larger than the top ring gap. This prevents the top ring from fluttering when exhaust gasses try to build up between the two rings.

 

If you've got blowby, your rings arent sealing either due to poor rings, or poor bore finish, distorter bore, or wrong piston to bore clearance

 

i have read this more than once for the 5.3 motor...maybe the .028 gap came from some formula

 

Gapless rings although the 2 piece design does leave no actual gap. Are gapped in the same manner any ring is, and they still have 2 ends which can butt together if the gap is set too tight.
Both the main ring and the secondary part have a gap and go into the bore the same way any ring would.

 

This may very well be. However, the original poster did not mention what size the engine was. Therefore, I cannot assume he is talking about a 5.3, and he must do the math and gap his own rings appropriately.

 

Very very well put guys. Sry. Its in reference to the stock short block in the hot rod artical. I will have a 6.0. Im going to go forged. With the rings the manufacturer suggests. Until then. I want to run it with the stock one. Since they did it in the artical. Alot of people have been talking about it and have done it. Seeing if there was any draw backs to doing that?

 

Yes, there will be SLIGHTLY more blow by. But you will not have a piston failure to to your rings binding.

99% of stuff in an engine is give and take. There are very few exceptions to this. You make one thing better and there are draw backs. You can go forged, but it costs more money and you may get pistons slap. You can open your ring gap, but you get more blow by. You can open up the ports on your heads to achieve max flow, but low end torque will suffer. You get a big powerful turbo, but you have lag. Get a really well breathing cam, but emissions and idle suffer. The list goes on and on. It's all in what you are willing to put up with.

 

Leave the gap alone in the JY motor

 

fair enough. i completely agree. thats why i was wondering about what the cons would be. My first car took me 6 years to build and only 3 months for an ex best friend with a meth addiction for it to come up missing and never see it again. lol so this time Im jumping head first into a turbo ls motor. I know with any car. Its all about getting everything matched as best as possible, within the best financial means possible. lol I have alot of stupid question so I rely on alot of other peoples trial and errors. It will see 14 pounds and on e85 is the plan.from what ive seen. thats about the safety point before pushing water. want to get as much seat/tuning time with the stock short block. rather grenade that, than forged. they are cast pistons aren't they? jy motor? i prob sound stupid... lol i guess it doesn't get much better than the fastest stock short block. what have you found? have you done anything with the gap? my buddy owns a junk yard. i could get a complete 4.8 with 4l60 for little of nothing right now but im holding out cause i want the 80 behind it. rather get them together so i know everything is there.

 

oh and.. are you running headers or manifolds?? what do you do to keep them together. those are some crazy times!

 

Manifolds, e85 and 14lbs will be no problem, assuming you will be running a 76mm or so.

Search my posts, I give out info on my setup, also lots of other good info on here if you do some searching.

 

i will def check out your builds. how many pounds of boost are you running?i have done a ton of searching and have been on here for quite a few years planning everything out. i want to push 650-700 rwhp with the boost up. That should be enough to get me into the 9's comfortably in a 2900 pound car. thought about going more toward an 80-88. i want to buy the turbo once and i can upgrade to it. thats still not a huge turbo for a 6.0l.