venetox

This is a stupid question, I know the correct thing to do is just get an extra ring pack. However trying to figure out how bad of an idea it is. Feel free to berate....

My mate is building his 1.6 engine, he accidentally missgapped one of his ring packs to about 0.029" instead of ~0.020", rest are fine.
In our country a new ring pack is at least a few months away.

To the people who have some experience building these engines.
How bad of an idea is it to just run the higher gap one and replace the ring pack when we pull the head in 6 to 8 months for head-work (and re-hone that cylinder)?
My understanding is that he'll have a bit excessive blow-by in that cylinder but there isn't really anything else that can go majorly wrong from it.
Alternatively I thought about potentially just running all of them at that gap since I don't like the idea of having 1 gapped too large and 3 correct, but I can't really think of anything that would cause damage.

Thoughts?

technicalninja

Run it loose but do not change the rest to match.
I've seen gaps as high as .050 run fine and not create excessive blow by in NA applications.
Change them down the road if you care.
It would be very interesting to do a leak down test on your engine after it's broken in to see if the gauge could actually see the increased gap.
I bet it can't...

soot

.020 is already a big gap, what rings/pistons are you using? You have a target HP/ RPM in mind? Which ring is it?

I'm not exactly and expert, but I am usually willing to 'good enough' some things, but that seems pretty damn loose.

edit - listen to smarter people than me. Apparently .020 isn't that big for a second ring. The main thing I've heard is that you want the second ring to have a bigger gap than the first to prevent pressure build up between them

sixshooter

iTrader: (12)

Wut?

If no pressure builds between then then you may as well have no second ring. You misunderstood or were misinformed.

soot

Huh, well thanks for correcting me. I've seen that exact phrase on this site at least 1-2 times when I was researching my ring gaps and no one raised any alarms

Edit: this is straight from Weisco, seems like my statement is correct?

"There’s a clear technical reason for that extra clearance - “We like to see the second ring end gap .001-.002 larger than the top ring so it does not lock in any compression that gets past the top ring,” says DiBlasi. “If combustion gasses go past the top ring and the second ring gap is less than the top ring, the gas will not pass the second ring. The gas will be forced to return back to the top ring and press up on the bottom of the top ring. That will lift on the bottom side of the top ring, reducing its seal even further.”