Ring Gaps

[Wolf_Zero]

Well I can't sleep and I'm going to be picking up my block, crank, heads from the machine shop this weekend. I've gotten to thinking about ring gaps. The stock manual says to do .3-.45mm on the top and .45-.6mm on the second (for the turbo's). I've done a bit of reading and I've basically concluded that you want a fairly large gap on the second ring as it helps prevent the first ring from fracturing. Now my question is how much would I actually want to gap the rings? The car isn't going to be to highly modified for now, just my old 13g's, bpu stuff and an aem. However, it is going to mainly be used for road racing/auto-x. So I was thinking I would want to end up in the higher end of both spectrum's for the gap to allow for more expansion since the engine would be under wot for easily 15 minutes on a road course. I was thinking around the neighborhood of .35-.4mm on the top and .65-.7mm on the bottom (if not even a little larger) based off of what I've been reading. Anyone else have some input they'd like to add? I doubt I'll actually be putting the motor together this weekend because of phone issues at work and my parent's computer is also having issues. But it's something I'd like to go ahead and get figured out so that next weekend I can at least get my motor together. Any input you guys add would be appreciated

[Twin-Turbo]

I would just do the big end of what is recommended (.40 up top and .55 on bottom). You don't want to have compression loss. Thermal expansion is an important thing to stress, but really, over gapping them doesn't sound like the best idea.

[moffman93']

I didnt know you were supposed to gap rings? I was under the impression you just order them to spec and apply them. Then use that rang clamp(whatever its called) to close them when you put in into the cylinder.

[Wolf_Zero]

[quote=""Twin-Turbo""]I would just do the big end of what is recommended (.40 up top and .55 on bottom). You don't want to have compression loss. Thermal expansion is an important thing to stress, but really, over gapping them doesn't sound like the best idea.[/quote]

The top ring I was going to stay within factory spec. But people like ray are saying to go fairly large on the second ring. Well the thread I mainly saw was made by IPO, but ray did confirm the info (at least for the second ring). The number IPO was throwing around was between .66-7mm though. But all they use their car for is drag racing. I realize I don't want to go to big on the gap, but based on the gaps I'm thinking of now I'm already less than what some other places are saying for the intended use of the car. The "magic number" always seems to be ~.004" times the bore size for the top and ~.0055" times the bore size for the second.

[quote=""moffman93'""]I didnt know you were supposed to gap rings? I was under the impression you just order them to spec and apply them. Then use that rang clamp(whatever its called) to close them when you put in into the cylinder.[/quote]

I'm not aware of any place that sells pre-gapped rings, they may sell rings for larger bores, but they don't actually come gapped to spec. They're usually out of spec (to little gap) so that you can change the gap to what you would like to use.

[Wolf_Zero]

So no one else has any input? So much for 3stech folks that come here, yeesh

[niterydr]

[quote=""Wolf_Zero""]So no one else has any input? So much for 3stech folks that come here, yeesh [/quote]

I don't really tech it out on this forum, sorry.

It is customary to run a tighter 1st compression ring compared to the secondary ring. Ring gap is based off bore size.