so im curious what kind of experiences you guys have with ring gaps.

currently putting together an 82x89mm lsvtec, with ycp gsr pistons. both the rings that came with the pistons and the set of hastings ring i bought separately have gaps imo too big right out of the box. the top rings i get 18-19 thou which i can deal with then i move to the second ring and its like 24+. great for boost but im thinking too big for daily driver on motor. its not a crazy build, static just shy of 11:1 and itr cams

this **** always happens, i have like 3 other sets of rings at 81.5mm from builds over the years that are too big for motor but good spec for boost. you guys just throwing these motors together as they sit or do you keep buying rings till one is good?

 

I have encountered the same thing with many piston sets. It's annoying, as you hope they would be a touch on the tight side. I generally don't open the gaps up like crazy, even on forced induction applications.

 

is there a theory/reason why the second ring gap is designed to be larger than the top ring gap

 

My srp pistons came with ring sets that were exactly as you described. Give or take a few thousandths. In my case im building it for boost but it works perfectly fine as an na engine.

Supposedly by opening the 2nd gap larger than tge top it allows blowby gasses to enter the block instead of pushing up against the top ring and causing it to flutter

Actually maybe they werent as big as ypu described. I think I got like .016 top and .019 2nd, and .024 for the oil rails

 

.016 and .019 are what i got using the multipliers that used to come with ring/piston kits not sure if they do anymore. i think it was bore x .005 and .006. im even willing to give up a bit of gap but not from .019 to .024 thats like 20% too big. id also be worried if the 2nd gap is too big that some oil can get between the rings and coke, build up in the ring lands, and lead to problems down the road. this is intended to be my daily, which ill put 16-20k miles a year on id like to own it for a few years while i pay off some bills and maybe try and get a bigger house.


for whatever reason ive been using the je proseal rings in my boosted motor. the top ring has always come out borderline too big but useable, but the 2nd ring is smaller so i can file the gap to spec. may just have to get a set of those, but they are like 100 bucks

 

I've assemble a stock Ls with similar end gaps. No noticeable blow by, no smoking and certainly no loss on compression. Engine has about 16,000 miles on it and still healthy as an ox.

I agree that on a NA engine I try to target .016-.017 top ring and .020-.021 2nd ring, however .003-.005 won't make an incredible difference. I'm usually more concerned with cross-hatch and cylinder taper or out-of-round.

 

isnt most of the gap, not a gap because most of it sits on the ring land

 

The only way to do this properly is to bring your pistons and rings to the machine shop along with your block. This way the block will be bored and honed to the proper spec for your pistons. A good shop will gap and number the rings as well.

Otherwise you're hoping and guessing for a correct fit, which is unlikely.

 

Uhh no. Piston ring gaps have absolutely NOTHING to do with piston size. They only care about bore size. This can easily be set by yourself with a file and a set of feeler gauges. There is nothing you can do if they come right out of the box too big for your specific applications bore size.

Ring flutter prevention / reduction.

 

^^^

once pressure is past the first ring, what do you want to do with that pressure

 

pistons always go with the block, along with my ptw requirements, .0015 in this case. just to double check the machine shop, i pulled out my dial gauge and checked the bore its kosher.

ring filing is pretty straight forward, ive done it on about 15 motors ive built for myself/friends over the years. unfortunately if the gap is too big out of the box im helpless

 

So what would u guys do. Toss it together or try anither set of rings?

 

If it's going to keep you up at night get a set of rings the next oversize up. The rings would need to be filed a lot, but you will be able to target the end gap you want. Although it may be difficult finding 82.5mm rings.

I would run it as is, so long as the cylinders have 0 taper and out-of-round.

 

That was my thought as well. You can always call some ring manufacturers and see what they can get to you for 82mm rings and what the gaps are out of the box. I know in the domestic world I can order rings that come from the factory will almost no gap and can be filed to any spec the builder desires. If I remember right the JE piston rings I put in my chevelle came from the factory with a .004 gap out of the box which left tons of room to play with.

 

yeah so im pretty mental and ordered a set of je proseal 82mm rings. damn things were 110 bucks. i remember a few years ago when the proseal rings were like 85 dollars. i blame obama lol.


anyway, they came in the mail today and i quick threw one of the top rings in and it had a gap of .01 out of the box so im good to go and file to my own specs. lesson learned for next time skip the hastings and go right for the je's. anyone need a set of hastings rings lol

 

Are the rings the proper thickness for that piston set?

 

That's cheap . . . my total seal gapless tops with napier 2nds were $330 for the set.

 

1x1.2x2.8mm. i spend like a half hour checking around online for specs and part numbers before i bought them. i think they are actually for a vw vr6 which seems to use an 82mm bore actually