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S.B. International, Inc. is the exclusive marketer of J-LOY™ brand valve seat inserts. All J-LOY inserts are premium (hard) seats with a typical hardness range of 35-40 Rockwell "C" Scale. All valve seat inserts are individually cast to ensure proper material transfer and formation. Different alloys are utilized depending on the specific requirements of an engine or fuel delivery. The following information provides explanations for part number schema, materials, application usage and cutting procedures.


Basic Part Number:
4 Digits (Nominal or Actual Outside Diameter)

1 Thru 49 = Different I.D. & Depth Versions
50 & Up = Oversized Inserts for Aluminum Cylinder Heads
C = Stellite #3 or Tribaloy Cobalt Base Materials
E = Factory Installed Insert & Basic Part Number Is Actual O.D.
N = Star Series Non-Magnetic Material
PM = Powdered Metal
ST = Stepped Outside Diameter


High-Chrome Premium Grade Material with 1-9/16"
(1.562 Nominal O.D.)

Same as SB1562-1 except Star Series material.

Same as SB1562-1 except Powdered Metal Material

Factory-installed insert with 2.088 actual O.D.

SB2088E-1 + 030
Same as above except +.030 Oversize with 2.118 actual O.D.

(Incl. Passenger Cars, Light & Medium Duty Trucks, Tractors, etc.)     

1. Cast Iron Cylinder Heads
For ease in selecting and stocking inserts our part numbering system incorporates the cutter size as the basic part number on universal size seats. For example: SB1625-1, "1625" indicates this seat requires the use of a 1-5/8" cutter. Actual O.D. is 1.630 allowing for press fit. For factory-installed replacement inserts, the basic part number is the exact O.D. followed by suffix "E". For example: SB1678E-1, "1678E" indicates a factory-installed seat with an actual O.D. of 1.678.

2. Aluminum Cylinder Heads
The same part numbering logic is used for these inserts and they are identified with suffix 50 & greater. NOTE: These inserts are oversized from the OEM Metric size to the next largest standard U.S. cutter size. For example: SB1500-57, "1500" indicates this seat requires the use of a 1-1/2" cutter. Actual O.D. is 1.507 allowing for .007 recommended press fit for aluminum heads. These inserts also have a blended radius on the leading edge to prevent damage to the counter-bore during installation.


J-LOY inserts for Heavy Duty Diesel Engines (Caterpillar, Cummins, Detroit Diesel, Mack, etc.) are supplied in materials that meet or exceed OEM specifications for the particular application. Standard size inserts are exact O.E. duplicates dimensionally and oversize inserts have been designed to meet particular requirements of the aftermarket.


A Super-Premium valve seat insert is available from SBI. This valve seat designated "STAR SERIES" is a true Nickel Based Non-Magnetic insert developed for automotive and light to medium duty exhaust applications operating on Propane Gas (LPG). Due to a variety of factors, certain exhaust valve seats require a higher hot hardness characteristic. The Star Series insert was developed to retain hardness beyond 1600° to combat these high temperature engines. As alternative fuel is becoming more commonly use, it became apparent cylinder heads were experiencing premature and severe exhaust valve seat erosion (recession). This erosion was noted on hi-chrome stainless seats as well as other manufacturer's nickel base material. Using the Star Series valve seat insert in these applications will eliminate common wear issues and provide a greater longevity. We are presently offering over 100 different sizes and part numbers are the same size as our regular Premium grade seats with the addition of suffix "N" (Non-Magnetic). For a complete listing please refer to numerical or progressive listings found in the reference section of catalog.

It should be pointed out the above material should be more than adequate to handle exhaust applications for Gasoline and LPG fuel. Many customers have used and continue to use regular type Premium valve seats for these engines and report no problems. We believe many failures may be caused by, but not limited to the following factors:

  • Improper air-fuel mixtures
  • Improper timing
  • Emission control devices
  • Stop and go operations. (Excessive idling and vehicle weight, Abusive operation, etc.)


As anyone who has machined factory inserts in late model heads already knows the technology for the production and use of PM valve seats has been around for some years now. The challenge for the seat manufacturer has always been to provide a consistent material with excellent wear characteristics combined with being easy to machine, the latter being a property the OEM does not require when building a new head. In fact after the engine has run for some time the OEM seat will tend to work harden and become almost impossible to machine.

This material is primarily suited for gasoline applications. The material incorporates ease of machining, has consistent quality and takes advantage of the cost savings associated with this new technology.

Frequently Asked Questions (FAQs)
on Powdered Metal Inserts

How do I know if an SBI Powder Metal Seat is available for my applications?
Look up your engine in the application section of the catalog. If a Powder Metal Seat is available, in the note column of the Valve Seat Insert section will indicate availability.

Can I use an SBI Powder Metal Seat for Diesel or Propane applications?
We do not recommend the use of SBI Powder Metal Seats for these applications. Use the seat recommended in the application section of the catalog.

How do I machine SBI Powder Metal Seats?
Depending on type of machine, increasing spindle speeds by up to 50% should achieve desired results. On an SB1562-1PM seat we recommend using about 350-400 RPM to achieve the best surface finish.

What cutter life will I experience?
Testing has indicated from four to ten times as many seats before having to sharpen the cutter. It really depends on what is cut prior or after cutting the Powder Metal Seats.

Are there any productivity gains?
The faster cutting speeds and longer tool life will greatly increase machine output. The floor to floor time will be substantially improved and machine down time will decrease.

What kind of surface finish can I expect?
Our Powder Metal Seat will provide one of the best finished seat surfaces of any seats available in the industry. Using a sharp cutter and the correct spindle speed, you can expect a consistent "mirror" finish on the cut surface.

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S.B. INTERNATIONAL, INC. / 2108 Utopia Ave., Nashville, TN 37211 / Order Desk - 800.THE.SEAT (800.843.7328)
General Inquiries - 888.THE.SEAT (888.843.7328) or 615.248.6281 / Fax 615.248.6377