I have file fit rings. This means I have to install each ring in it’s bore in the block, measure the gap, remove the ring, file it, recheck etc etc. A very time consuming task. Since I want to be able to do this anywhere I took a 6 inch diameter piece of aluminum, rough bored it to slightly under the 4.500 bore size and then while checking the bore of the block using a bore gage I finished boring the aluminum sleeve to exactly the average of the bores in the block.
This gives me a portable cylinder that I can take anywhere and work on the rings. I was planning on leaving about .002 undersize gaps so I can actually custom tune each set of rings for it’s bore but I will be very close.
As they come in the box they are almost zero gap.
Ring specs call for about .004 per inch of bore for Moderate performance, .0045 per inch for drag racing, .007 for nitrous drag racing and .006 per inch for supercharging.
Since I have a 4.5 bore it calls for about .026-.027 for my top ring.
The second ring should be about .002 LARGER gap then the top ring.


To keep the rings square in the bore I made another aluminum piece that pushes the ring down in the bore and keeps it straight. Just start the ring in the bore and put the plunger on top of it an push down. The ring ends up perfectly square in the bore.



Then you use a feeler gage and check clearance. If it is too small and all of mine are way way too tight you file fit each gap. I will use a power ring grinder or wheel to increase the gap. That should give me something to do today.

 

That is how my engine was assembled - I've never done it but now I know why I paid extra for that process.

I was told that using file-cut rings would more or less, ensure that the motor was as good as NEW, not just another rebuild. In doing so there's no breakin procedure.

I've driven mine hard ever since it had just under a hundred miles on it. Never a problem.

 

Thats some nice stuff there...I file fit my rings as well... though I have one question...

Doesnt this mean you will be doing this "time consuming task" twice? thus using twice the time than if you just slaved over the engine block in the first place?

I know I would prefer the rings custom fit to each cylinder, in lieu of fit to a single 'average' dimension..still.. wish i had your machining skills and tools - good work

 

I agree, with the tolerances between individual bores always present
I would just file each ring to fit the respective bore and when done assemble them to the piston marked as destined for that bore. I don't see how this works any quicker, especially when you have to consider the time to make that tool...not saying that's not a nifty tool..it is.

 

Real Men use gapless rings in performance engines.

Norval - nice machine. I've been using gapless because of having the pin s in the rings because of 6 inch rod and long stroker small blocks

http://www.circletrack.com/techarticles/58040/

 

The break in process is the same. All I am doing is adjusting the gap in the rings. It has nothing to do with breakin. It is time consuming but guarantees a nice fit.

 

Yes I am doing it twice. The first time is in my office at work. I can take all the time I want getting the ends nice and square and I have about zero gap now. I have about .024 to take off and I can take my time, do it on work time and just fine tune at home.
The students are gone, the place is empty, I feel all alone
I am just doing the time consuming part here at work.
I do have a power gaper, a small grinder dedicated to doing just rings so that helps. No file is used.

 

Mark I can do it in my office, I just plug in the power ring gapper, take my portable bore and start play away. I have to remove about .024 since the gap is almost zero now so I can work slowly, on company time and get so close I might not need hardly any adjustment. It takes time and patience to remove the .024 and keep the gap square.
As for the tool I roughed it on a huge industrial lathe here at work and only fine tuned it at home. I left .020 on for final turning.
I used the exact same bore gage, same setting and checked the motor bore frequently as I was doing the portable sleeve.
I spend about 15 minutes in my lathe getting it to what I wanted.
I have a whole month of being just about the only person left here at work. I take off in the busy times, not the slake times like now.

 

They never mentioned that option. I got everything from Eagle. Wish I had those gapless rings right now

 

Did you read this circle track article, Norval? I'm not saying they are the best thing since sliced bread, but do know from leak down testing on my 383's that I was able to get all cylinders to less than 3% leak down on new refreshed motor.

That's even using the thin racing rings on the JE forged pistons. the problem was degredation within a short time period. Thin rings and 7500 rpm with a 3.750 stroke made for very high piston speeds. I changed to gapless on my first rebuild and was impressed. I've since used them on some other project motors.

 

Man...that is pretty cool. In your spare time can you make me just one of the "plug" parts that pushes the ring into place? That would speed up things immensely! I spend a lot of time getting them square....just never have cheeked up to get one of the tools.

Just kidding....I'll pick one up one of these days.


What rings did you end up with? Are they the same type you've always run? I assume you've about figured out whatever works in your application and the 540 would be the same.

I know lots of folks really go for the gapless style....and I know they do well in some testing...but I think a dynamic running engine acts a lot different. I always wonder why the OEM and NASCAR and the majority of big time race engine builders don't use them?

I've had great luck with basic Speed Pro's and currently am running Mahle's just to try something new. They are doing fine too. In the past I've used SRP's...bu they are just repackaged Speed Pro's. The Howard's ones are also repackaged Mahle's. Not that many actual mfgs out there.

All that said, I know ML67 is currently using gapless in his 548 and is having good luck. But he went through several tries with different mfg's before they worked right.


JIM

 

My rings were choosen by Eagle and they are perfect circle. They also choose the bearings.
I would be pleased to send you the complete gapping tool when I finish with it. It is a 4.500 bore and tool for squaring it.
You have given me some great advice and I would like to give something back.

 

Me too.

I like 'em.

 

when i was looking into the gapless, they were selling (trying) sets with gapless rings for the top and second groove. i gathered that there was some issue with crankcase breathing(?), loss of ring seal(?), whatever. did they ever identify the solution? which proved out best, gapless top or 2nd ring?

 

I just finished gaping the 16 rings. I set them at .022 or .023 and marked each one with a pencil so I know which is which.
this is how I recommend doing them.
First I do have a power gapper. I do NOT file. I set the ring gapper up on a table and used a large magnifying glass over it so I could really see. I left it running at all times.
I set the portable cylinder I made right next to it so I didn't have to move very far.
I take a ring and it has a dot on it. I ALWAYS put this dot at 1 oclock. I NEVER grind or touch that side of the gap NEVER.
This is my reference edge. It is straight and square.
I then use a sharp pencil and scrip a line right next to the gap I want to grind. I then put the ring on the table and gently hold it against the grinding wheel and use the line as a reference as I slowly remove some material. After a few rings you quickly can quess very closely how far to grind.
I then take the ring and put it in the cylinder.
This is easy. DON'T fight the ring. Insert the gap at 12 oclock and just stick it down in the cylinder and push from the 6 oclock position. Once the ring is in the cylinder and it just about falls in rotate the gap up towards the top of the cylinder deck surface. This compresses the ring and closes the gap. Then take the squaring tool and push the ring down in the bore to square it.
I use 3 feeler gages. I want .022 so I use .020, .022 .024.. This is a go, no go situation. If the .020 fits and the .024 doesn't you are in the right area. I also use the smaller .020 to check parallism of the gap. If it fits on the inside of the ring and not the outside and this is how the rings often gap you just slightly touch the ring to the grinding wheel and straighten it out.
To remove the ring just pull straight up on the gap and it slips out of the bore.
Agian don't fight the ring trying to compress it, insert the gap down in the bore, push from the 6 oclock position until that spot is just below the bore deck and then rotate the gap up by pulling up on it. This is easy, doesn't stress the rings or you fingers and lets the bore close the ring.
I took only a few minutes per ring and suprissingly got them almost spot on each time in the second fitting. Took less then 5 minutes per ring working carefully and slowly.
I then marked each ring with the gap I got with a lead pencil.
I will later custom fit each to it's assigned hole
I very fun job, one that I was dreading but it went easy. Well under an hour for the total job.

 

I love it..... If you have the slow time in the office it seems like a great idea. I thought there where some issues with the gapless rings at higher RPMs that had not yet been resolved?

 

You're right...it's not too bad to do. I usually just pull a chair up and sit down beside the block and have at it. Just one of those things you do to make everything "right"!!

JIM

 

 

For piston ring squaring tools you can sometimes get by with plastic floor drains from the local hardware store or plumbing supply. they are square enough for piston ring filing and have a built in stop, set the ring in the bore approximately 1" down and cost less than $3 in most instances.