Ramonn

So a little nervous to do this myself without proper tools I brought in my block with pistons and rings to get the rings filed down. (sorry for the imperial folks) I asked for top: 0.45 mm, 2nd: 0.50 mm.

What I got returned the first time:
1 2 3 4
Top: 0.40 0,45 0,50 0,50
2nd: 0,45 0,40 0,50 0,50

In doubt if I should even go back there, I returned them anyway and he understood and told me he will fix it.
1 2 3 4
Top: 0.50 0,45 0,50 0,50
2nd: 0,55 0,55 0,50 0,50

Well, I'm not going back there.. Those are my own measurements btw. Some of them are not even filed straight. You can easily tell butting them together. Since they are all pretty much oversized on a size that already was wide, not being straight may not even be a huge problem. But mainly I just want to know how bad it would be to just run them like this. Some people tell me deffo get new ones, others tell me it won't make a noticeable difference. I was hoping any of you have a clue what to do

Some background info
2004 1.8 bored to 84mm, Supertech P4-MA8400-N4 8.6:1, wiseco rings. EFR 6258 running 18 psi would be a moderate start.. But I'm building it to be able to handle a lot more.

ryansmoneypit

iTrader: (6)

Lol, that's about double wide as they should be. Are you planning to run 50-80 psi boost and a 200 shot of nitrous? Might be okay for that.

Ramonn

Really? Thanks for your reply. I have never bored cilinders before or had file to fit rings. I've always gone with what's in the box lol.

This time I stuck with the ring charts. It says (for street moderate turbo) bore x .0050 inches for the top ring and bore x .0055 inches. This resulted in 0.42 mm top ring and 0.46 2nd ring. Since the feeler guage only does 5/100 mm I wanted to go with a tight fit for the 0.45 and 0.50 mm.

What do you recommend? Thnx

technicalninja

.45mm is .018 inch
.50mm is .020 inch

The metric sizes are causing confusion.

Seems OK to me, maybe a bit tight if you are planning boost above 20 psi or the addition of nitrous.

More important is to deburred edges where the rings have been filed on. The edges in the gap should not be razor sharp. A microscopic bevel is all you need.
If they are sharp they can "dig into" the ring lands which will ruin your day. There are tricks to this filing. I file "inwards".
This is especially important where dressing the edge that touches the bore as the ring may have an outer coating that can "flake" or chip if filed in the wrong direction.
For this deburring I commonly use wet/dry sandpaper 600-1000 grit (the dark grey stuff) backed by a straight edge (file or small ruler) and WD40 as a cutting fluid. The final result is a 90 degree edge that feels "soft".
Take your time, be gentle...

I like my ring gaps straight and only file one side leaving a factory edge to gauge straightness.
Depending on the extent of the angles I would probably run the rings you have now.
I might open them a bit if it will correct the angle issue. A bit is .001-.003 inches.

Having slightly oversized ring gaps will not hurt an engine.
Having undersized ring gaps can kill an engine.
If the ring ends touch during operation you're toast.
More heat-more boost-additional power via nitrous= greater ring expansion= need for larger ring gap AND the need for additional piston to bore clearance.
Having larger 2nd ring gap may improve top ring sealing.

Looking at the second numbers I'd file 1 top ring to .50mm and 2 lowers to .55mm which is .020 and .022 inches.

What is the piston to bore clearance?

Ramonn

Yea ok this helps a lot I'm deffo not planning on nitrous. Stock trans so 20 psi will probably be plenty.
You name a lot of good things to take care about when doing the filing. Thing is, I let a "professional" do it. I do have some fine 600 and 1000 grit sandpaper for wet sanding. Thanks for the tips, I may check and see if I can perfect them myself. And yes I heard larger 2nd ring gap is usually beneficial.

One question. Can I see if a coating may be chipped? they all look fine, don't feel sharp and it looks like only one edge is filed every time.

Ramonn

Thnx for the tips btw. I didn't get around to work on it until today. I took a nice flat thin metal strip that I used as a backing for some 1000 grit with some wd40 worked like a charm.

Upon close inspection with a nice camera before I started one of the rings looked like this.



I figured I couldn't mess it up any further so gave it my best shot. Turned out very well imo. Went much smoother than expected.

Icould straighten them where needed and all top rings are now 0.50mm, all 2nd ones are all 0.55mm. both rings for piston 4 are a little wide.. so much that I could force in a 0.55 top and 0.60 for the 2nd. Figured I would use that as a set for one same piston.

LeoNA

I would not worry too much about it. .020"/.5mm is more then is needed. The dressing of the edges and parallelism of the end gaps can be an issue but its not as large of a factor as the overall gap. Too much and you will have excessive blow by. Too little at the min condition might cause butting. Butting even in an FI engine is rare. The gap only gets larger with wear. The edges can be dressed with a veryfine stone or a ceramic lap. The bore side corners should have a very small chamfer .002-.005". Good luck.