Capri V6 Essex block with 3.879 inch bore. 5/64 top and 2nd ring, 3/16 oil ring. The only rings I can find are Sealed Power 3.895 in or 3.875 in. The gaps are already fitted on both. Both are Iron with facing in Moly top ring and Cast Iron 2nd ring.
Would you run the larger rings and fit the gaps or run the smaller and get blow-by.
To get better ring selection I would prefer to not get new pistons made at this stage.
Ring size
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cjperformance
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Re: Ring size
You're a long way from ideal either way. If i had no other choice (and i have had this situation before) i would go for the bigger ring set and file to fit.
Dont forget to check oil rail end gap.
Dont forget to check oil rail end gap.
Craig.
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mag2555
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Re: Ring size
The more you file a ring that's not made with the intension of being gapped the more oval the ring will be and with that comes more blow by then a big gapped ring that is round!
Give total seal a call, as they can make you what you need.
The rings you use also need to tuck / hide into the groove by a few thousandth.
If you are going to manually file a ring that has a Moly face you should only do so by pushing from the face to the back of the ring otherwise you can flake off the Moly face, then use a soap stone or some 280 grit wet or dry paper rapped around a nail file board to roll over all the sharp connors and edges on each end of the ring.
Also if your used Pistons have anything more then .004" compression ring to groove gap your going to some blowby just from that excess gap.
Give total seal a call, as they can make you what you need.
The rings you use also need to tuck / hide into the groove by a few thousandth.
If you are going to manually file a ring that has a Moly face you should only do so by pushing from the face to the back of the ring otherwise you can flake off the Moly face, then use a soap stone or some 280 grit wet or dry paper rapped around a nail file board to roll over all the sharp connors and edges on each end of the ring.
Also if your used Pistons have anything more then .004" compression ring to groove gap your going to some blowby just from that excess gap.
You can cut a man's tongue from his mouth, but that does not mean he’s a liar, it just shows that you fear the truth he might speak about you!
Re: Ring size
3.875 set all day long. You will have an extra .012 end gap, a little less oil ring tension. Fitting the larger ring set may require dykes. 
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engineguyBill
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Re: Ring size
Use the 3.875" rings. You are better off using the rings that are closer to your net bore size and we recommend that you keep the ring within .010" of the bore dimension for best results.
Bill
Perfect Circle Doctor of Motors certification
SAE Member (30 years)
ASE Master Certified Engine Machinist (+ two otherASE Master Certifications)
AERA Certified Professional Engine Machinist
Perfect Circle Doctor of Motors certification
SAE Member (30 years)
ASE Master Certified Engine Machinist (+ two otherASE Master Certifications)
AERA Certified Professional Engine Machinist
Re: Ring size
Should have couple sets 3.880" (finished bore size) on the shelf here in 5/64"-3/16" pack, "std" tension!
Thanks, Gary in N.Y.
P.S. Only have them available for V-8's however, not "6's"?
Thanks, Gary in N.Y.
P.S. Only have them available for V-8's however, not "6's"?
Sept. 2019 - Drag-Week Winner - New York Street Ride 7.23+ @ 196+ @ 3800#+
Re: Ring size
Thanks for the replies. For now I will fit the smaller size. The existing block is a bit thin in the walls as it is so oversize. I have another block as rare as they are and will start again with that.