Kubs

I am FINALLY starting to put together my engine for the race car. I am doing the work myself, with my dad and grandfather advising along the way (they have built a few engines in the past and this is my first). I wanted to get opinions on proper ring gap. I have file fit rings for my 0.030" over 350 block. I know one gap has to be bigger (ie top ring gap bigger than bottom or vise versa) but not sure which one. This will be in a full time race car if that matters.

ddahlgren

Top ring bigger ask the manufacturer what gap they want for your application. They will give a minimum if you blow past it by a thou or two do not agonize over it, miss by .010 be unhapy. I know years past Speed pro had rather specific numbers depending on application. It all varied N/A supercharged nitrous etc...

engle1147

Consult your piston's manufacturer for recommended gaps for your piston type. Since this is a full time "race car" you might even consider using low-tension rings:http://www.stockcarracing.com/techar...p/viewall.html

Nathan Plemons

Several years ago there was a company that created a so called gapless ring. It was supposed to make more power due to less blowby. Seems like I heard they worked well but you didn't want to use them with a power adder.

I don't know if they still exist or not but just figured I throw it out there as something you may want to research a little.

engle1147

These guys below sell low tension gapless stuff....check out size/application seach functions as well.

http://www.totalseal.com/

Kubs:
Since this is your "first" take your time and do your homework.
Like anything else these days there is a ton of choices out there and opinions on which way to go will vary greatly.

TTOP350

The specs you need will be in the package of rings you buy.
If you have your rings open the package and read the instructions.

rklessdriver

What ring set do you have? Need to know what your working with before I can make a recomendation.

Alot of people still set the top ring wider than the second ring - but OEMs and alot of ring mfgrs have moved to setting the second ring a few thou wider than the top ring in the past 7-8yrs....
Will

ScaryFast

^^THIS^^

Mine were .024 top and .022 bottom, for what it's worth - different motor, apples to oranges. But as long as you're well above .010...welll...you probably won't blow up.

Don't forget to line up the oil ring as per the package, also. Who's rings did you get, J&E? I have some used ones I can sell ya, garage kept, never raced

Kubs

I do not have the rings with me. My race car and parts are stored at my dad's about an hour away. I will be in town tomorrow I will see if I can snap a picture of the box and get names and part numbers.

probably...... and I will have to think about your generous offer...
I know the pistons are JE, but I ordered everything through the machinist who did the block work. He made sure everything matched up, and when I went to pick up the block this past weekend I got the rods, pistons, rings, bearing, etc with it. I will make a list of everything when I go into town tomorrow.

Kubs

I am doing as much homework as I can. I have my life savings into this thing so far. I only get one shot at it!

1963SS

I always gap the second rings about .004 more than the top rings. Several years ago this was wrong. Folks thought that because there is not as much heat on the second ring the gap could be less. This allows the gasses that pass through the top ring gap to actually build up pressure between the top and 2nd ring. What this pressure does is keep the top ring from fully seating under high loads and fluttering. That is not a good thing.

The current school of thought and proven at Engine Masters and most other places is to open up the second ring gap to get rid of this pressure. Apparently it's not all about heat. Some common gaps for applications are

Street use top ring .018 and second ring .022
Hot Street and Race would be .020 and .024 second ring
Race engines can use .022 and .026

Nitrous is more and so is forced induction.

At least that is, as always, IMHO.

Crepitus

i would use the manufactures recondition for oval track use (usually a couple thou looser than street on the top ring). a couple thou loose wont hurt a bit.
I use a clean piston to square up the rings in the bore. A touch of 30wt ND is a good idea. be careful not to scratch anything, piston, bore, ring face etc. Also watch out that the ring ends dont butt solid together, if there is taper in the bore they will be looser at the top. final check gap throughout the ring travel in the bore. be sure the hone finish is correct for the type of ring face you have chosen.
A fine file in a vice and the ring in your hands.
stroke slow and carefully from the outside toward the inside only. Be very careful to keep the everything as square as possible. Carefully, gently deburr the edges, with a fine file or stone, you dont need a beveled edge just be sure any burrs are gone.
Installation; again dont scratch anything, a cheep set of piston ring pliers works fine to spead them. Dont spread any more than necessary. Drop the piston rod assy into a soft jaw vise, gently and no need to be very tight.
install the oil ring spacer with the ends butted together not overlapping. roll the oil rings on. position gaps as per manufacture recommendation, be sure the spacer ends are still correct.
Identify the top side of the 2nd ring. There is usually a dimple that should be facing up. use the pring pliers to gently spread the 2nd ring open barely enough to install. Top ring same as first.

Be prepared, make a plan, think every step through, have fun, triple check everything have fun. hope I presented this accurately If there is anything that should be added please speak up!

Crepitus

Good Stuff Thanks for passing this on

Kubs

Wow! lots of great information on this forum. Thanks guys!

TTOP350

I just did a 400 stroker for my car, I tightend the top gap all the way to .014 and the 2nd was around .018 (Ill have to dub check my notes). It was almost the same settings as a BES 400 from the engine masters challenge awhile back. I tore it down after a hard 3k miles just to check things and no ring butting at all. It also didn't seem to have as much oil being sucked into the Tbody. Going to hone her up and use the same assembly settings.

1963SS

That's gotta be real tight on a 4.125 bore. I don't have any idea why anyone would even attempt that. It would scare me to think about that little gap. The least I would even think of for an engine challenge would be .016 and .020. Those engines aren't necessarily made for the long haul. They have to make good dyno numbers with no regards for real world driving and racing. Don't even think about going that tight or you'll stand a real good chance of tearing the top off the piston. Again IMHO.

TTOP350

I just looked at my notes, I went .015 top and .019 2nd (not sure where I was getting the .014?? bad hand wrighting and gettn old I guess). When I pulled it out after the break in they were already .016top and .020 2nd.

BES did .016 top and .043 2nd with .020 oil ring..

Here is a link to the story/motor i kind of semi followed on my build. I have more cubes, compression, solid roller cam and AFR 235s all that under a welded and ported mini ram. Fun stuff

http://www.popularhotrodding.com/tec...e/viewall.html

ScaryFast

Now you guys have me thinking...I checked for the notes on my ring gaps and couldn't find them. I wonder if I what I posted above was backward, and it was .022 top and 0.024 bottom.

I'm going to pull the head off and measure

Kubs

I took a picture of the ring box today. They are Total Seal rings. Inside I also found a card with recommended ring gaps.





The card is saying to use a larger gap on the first ring, which you guys seem to think is opposite (which I agree with from a common sense stand point). Also they are showing a 0.014 and 0.018 gap, under street strip circle, which seems a little tight. Thoughts?

rklessdriver

Like I said SOME ring mfgrs have gone to opening the second ring up.... Some (TS for instance) have not.

.018 on the top ring is fine for what your going to be doing.

It's you choice on the second ring. Before 6-7yrs ago we always ground the second ring tighter than the top.... The opened up gap on the second ring is a fairly recent development.

Personally if I was building it TODAY - I'd set the second at .022 - but honestly anywhere between .014 and .022 is fine.
Will