093turbo16

iTrader: (2)

Well I got around to putting together my motor today and come to find out that the ring gap on the second compression ring is about 29 instead of around 22 where I wanted it. My top compression ring is at 20. How much will this hurt? I was thinking about just getting a new set of rings.

Now some things that might effect this:

Block is a B16A2: The pistons are Arias 81.5mm and the rings are from arias.

The pistons have a coating on the skirt. I am thinking that the coating on the skirt has pushed the bore to be bigger than just the normal piston, hence my big ring clearance up top. The pistons were miced and then the block was bored.

The motor is going to be used in a drag car and will see a good bit of boost.

Any help is appreciated, just looking for some options/opinions.

22psicrx

I believe it will burn a litttle oil . maybe a pint every 2000 mile. My engine builder left mine a little loose .

093turbo16

iTrader: (2)

Thanks for the comment. I am more looking for specifics on Arias pistons, I guess I am going to call them today, but they will probably tell me it is up to the engine builder... which is me, so that won't help too much, but worth a shot anyway.

blaze the chemi

I remember for a general rule, gap size is determined by bore size (in.) x 0.0055 for the top ring. In this case you should be shooting for 0.017- 0.018 in gap size. Since you are using it as a drag, making it larger should not hurt too much. I think for your application you should be shooting for 0.021 " at most. The secondary ring can have a larger gap, but not much. Call Arias to find out, but this is my input and what I went by when I rebuilt my engine.

093turbo16

iTrader: (2)

OK thanks man. I have rebuilt motors before. I thought everything was peachy, i was shooting for a looser gap because of the power I will be hopefully making on, for the top ring gap. I just didn't want the bottom to be so large. But I have also read that up to about .030 would be alright.

m R g S r

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93turbo16 &raquo;</TD></TR><TR><TD CLASS="quote">The pistons were miced and then the block was bored.

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measure em again....see if the builder (machinst) f'ed it up......could be possible....

maybe egg shaped cylinders? are you measuring both rings in the same spot in the cylinder? Is every cylinder the same?

Muckman

iTrader: (2)

The coating on the piston skirt isnt going to be thicker than 1 or 2 thousandths and that isnt going to affect your bore much if at all. - if your builder even compensated for it, most dont bother bc it isnt a big deal. So dont concern yourself with that.

But back to the original question. Ring gaps have a bigger tolerance than most people think. It would probably be fine but Id personally buy another ring set to fix that one. Or you can throw that ring onto the #3 piston.

093turbo16

iTrader: (2)

All 4 of the second compression rings are that big. I checked them at the same spot on each cylinder. I think it will be ok. If it ends up smoking alot, I will just re ring it. Since it is in a drag car it is no big deal.

I trust the machine shop, I am just going to go with it. I was really more concerned with the upper ring really.

Muckman

iTrader: (2)

I think you'll be ok too. I dont think it will cause you to burn or smoke oil either. The exposure of a few extra thousandths of an inch from one ring is nothing when compared to all the rings and orientation.

093turbo16

iTrader: (2)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Muckman &raquo;</TD></TR><TR><TD CLASS="quote">I think you'll be ok too. I dont think it will cause you to burn or smoke oil either. The exposure of a few extra thousandths of an inch from one ring is nothing when compared to all the rings and orientation.</TD></TR></TABLE>

OK sounds good. I will give it a shot, I didn't think it was HUGE, but I wanted a second opinion.