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Cast Iron Piston Ring, 4.00 Inch OD, 0.187 Inch Width, 0.14 Inch Wall Thickness

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Description & Features

This cast iron piston ring from Hercules Sealing Products features a 4.00 inch outside diameter.

It has a width of 0.187 inches and a wall thickness of 0.14 inches, suitable for applications where precise sealing is required.

SKU: SPR-4002

Supplier Part Number (MPN): SPR-4002

Alternate Part Numbers: C1DK99

Specifications

Brand
HERCULES® SEALING PRODUCTS
Dimensions
0.1875 in H x 0.142 in THK
grp Groove Depth
Grooves Must be at Least 0.015 in Deeper than the Maximum Radial Wall Thickness of the Piston Ring with a Tolerance of +0.003/-0 in, This is to Avoid Any Possibility of the Ring Bottoming in the Groove when the Ring is Compressed to its Working Diameter
grp Groove Width
To Permit the Ring to Slide Freely into the Groove, the Groove Must be at Least 0.001 in Wider than the Maximum Piston Ring Width with a Tolerance of +0.003/-0 in
grp Radial Clearance
The Radial Clearance Between the Cylinder Bore and Piston Should be Less than 1/3 of the Radial Wall Thickness of the Piston Ring to Ensure Sealing Effectiveness
Material
Iron
Series
SPR Series

Product Questions & Answers (3)

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Question by: Shawn M on Jul 13, 2025, 9:59 PM
So, this here ring... it's cast iron, right? Just wanna make sure it'll hold up for what I need it for.
Answer by: Customer Support on Jul 15, 2025, 6:55 AM
Correct, it's made from cast iron, known for its durability in sealing applications.
Question by: Tammy T on Jun 16, 2025, 7:26 PM
groove depth on these things, what's the minimum I need to machine to so the ring don't bottom out when it compresses?
Answer by: Customer Support on Jun 18, 2025, 3:52 PM
Your groove has to be at least 0.015 inches deeper than the maximum radial wall thickness of the ring. On top of that, you need a tolerance of +0.003 inches on the deep side with no minus allowance. That extra room is what keeps the ring from bottoming out when it gets squeezed down to working diameter. Cut it short and you'll have sealing problems real quick.
Question by: Jerry R on Jul 8, 2025, 5:10 PM
got a piston groove cut for a 0.187 wide ring, is this the right size or am i gonna fight it?
Answer by: Customer Support on Jul 10, 2025, 1:09 PM
The groove width needs to be at least 0.001 inch wider than the ring’s maximum width, and it also needs to allow the ring to slide freely. Since this ring is 0.187 inches wide, you want a groove width that clears that by at least 0.001 inch, plus the stated tolerance of +0.003/-0.

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