4N-5893 4N5893 Valve Seat Insert 3406 3408 3412 CAT Engine Parts Excavator Diesel

The 4N-5893 valve seat insert is the press-fit seat ring that intake and exhaust valves close against in CAT 3406, 3408 and 3412 diesel engines. It carries the compression seal, conducts combustion heat from the valve head into the cylinder head casting, and protects the head from seat recession when the engine works at sustained load. Held as a stocked line in our CAT Engine Parts range, every 4N5893 insert is machined and ground to OE seat geometry, so most excavator engine parts rebuilds can be finished without re-cutting the seat counterbore.

In a complete cylinder head job the seat ring is ordered together with the 160-9874 gasket kit, 3285574 connecting rod bearings and 1W-5283 companion inserts, so one consolidated shipment covers the whole rebuild. Every seat insert is produced from a high-chromium heat-resistant alloy and finish-ground on CNC seat grinders so face angle, seat width and concentricity stay inside CAT service limits through the full service interval.

The same 4N5893 insert is used on 3406, 3408 and 3412 cylinder heads fitted to excavators, wheel loaders, pipelayers, haul trucks, marine propulsion sets and generator sets. Because these engines run very different duty cycles, from quarry shot-rock work to continuous prime power, the seat ring has to hold its face under sustained heat and load rather than only in short intermittent use.

• OE-matched seat geometry: the 45 degree contact face, seat width and outside diameter keep valve margin position and installed stem height within CAT service limits after pressing.
• Heat-resistant alloy body: chromium and cobalt carbides hold hardness on the exhaust side, limiting seat recession, face pitting and valve guttering on high-hour 3406 and 3412 engines.
• Precision ground contact face: concentricity is held to a tight tolerance so the valve seals across the full face width, restoring compression and cutting blow-by after a cylinder head rebuild.
• Predictable interference fit: the outside diameter is ground for a stable press fit, so the insert lands square in the counterbore and stays locked without cracking the head during chilled installation.
• Repeatable batch quality: every lot is dimensionally inspected and hardness checked, so a repeat order for 4N-5893 matches the first one for fit and valve stem height.
• Fast rebuild availability: held as a fast-moving CAT Engine Parts item for workshops that cannot leave a 3408 or 3412 head waiting on one seat ring.
• Pairs with the stock rebuild line: the insert is quoted with 1W5283 seat inserts, 1609874 gasket kits, 328-5574 rod bearings and 1W8922 piston ring kits, so the complete head can be refreshed from one parts list.

One 4N-5893 valve seat insert fits the 3406, 3408 and 3412 cylinder heads, which makes it a practical stock line for a workshop servicing mixed fleets of excavator engine parts and power generation equipment. When several heads are rebuilt at the same time, order the seat insert together with the matching valve, valve guide and head gasket kit so the complete head is refreshed in one pass.

These numbers cover the wear parts most often replaced together with the seat insert. Send the numbers you already have from your parts list and we cross-check them against the 3406, 3408 and 3412 application before quoting, so a mixed order arrives complete instead of one seal or gasket short.

1. Clean the seat counterbore and measure the bore diameter before removal, so the new insert is checked against the original bore and not against the worn seat face.
2. Chill the insert and warm the head evenly where the service procedure allows, then press the seat in square with a piloted driver.
3. Check that the insert sits fully on the counterbore step; a partial seat changes valve stem height and causes rapid face wear.
4. Grind or lap the contact face only when the head has been resurfaced, then verify seat width and concentricity against the valve guide.
5. Confirm installed valve stem height and valve margin before final assembly, and check sealing with a vacuum or solvent test.
6. Fit the 1609874 gasket kit and the 242-9537 valve cover seal at reassembly, and check the 3591439 water seal on the 3408 head before the engine is returned to service.

Each production lot is checked at three stages: incoming material verification for alloy grade and hardness, in-process inspection of the outside diameter and seat face angle after grinding, and a final 100% dimensional and visual check before packing. Inserts are then anti-rust coated and packed in neutral cartons with separators, so the ground faces arrive without nicks or corrosion. For larger rebuild programmes we can quote with batch records and third-party inspection where the buyer needs traceability.

We supply CAT Engine Parts to distributors, engine rebuild workshops, fleet maintenance teams and equipment dealers. Our export experience covers buyers in Australia, Canada, Chile, Zambia, Congo, Nigeria, Ghana, Tanzania, Indonesia, Thailand, Malaysia, Zimbabwe, Brazil, South Africa, Saudi Arabia, Mozambique, Peru, Argentina, Vietnam and Kenya, and we regularly handle mixed orders where one air or sea consolidation carries several part numbers for a single rebuild schedule.

• Part number matching: send the engine model, serial number or the reference stamped on the old seat ring and we confirm the correct 4N-5893 insert before you order.
• Mixed orders: combine the seat insert with 1W-5283, 4N2927, 3285574, 1W8922 and other CAT Engine Parts in one order.
• Sample and trial orders: a small quantity can be supplied for a first rebuild so your workshop verifies fit and finish before volume ordering.
• Private packing: neutral cartons as standard, or your own label artwork where written authorisation is provided.
• Response for fleet tenders: send the full parts list and we quote the complete head rebuild requirement in one reply.

• Intake and exhaust valves for 3406, 3408 and 3412 cylinder heads, matched to seat inserts 1W-5283 and 4N5893
• Valve guides, springs, retainers and keepers
• Cylinder head gasket kit 160-9874 and complete overhaul gasket sets
• Piston ring kit 1W8922, pistons and cylinder liner kits
• Connecting rod bearing 3285574, needle roller bearing seat ring 4N-2927 and engine bearing 7M7219
• Service meter front cover kit 1P4923 and oil return seal 142-2329
• Cylinder head assemblies, ECU ECM module 348-2387 and complete excavator engine parts assemblies

Q: How do I confirm that 4N5893 fits my engine?
A: Send the engine model, serial number and, if possible, the number stamped on the old insert. We cross-check the application against the 3406, 3408 and 3412 listings before quoting.

Q: Is 4N-5893 supplied as one insert or as a set?
A: It is quoted per insert. Tell us how many cylinders and how many heads you are rebuilding and we will calculate the quantity needed for the job.

Q: Can you quote a complete 3406 or 3412 cylinder head list?
A: Yes. Send the parts list and we quote the seat ring together with the 1609874 gasket kit, 328-5574 connecting rod bearings, 1W-5283 companion inserts and 1W8922 piston ring kits in one reply.

Q: What is the minimum order quantity?
A: 12 pieces per part number, and smaller trial quantities can be arranged for a first rebuild.

Q: Which payment terms do you accept?
A: T/T and Western Union as standard, with L/C available for larger confirmed orders.

Q: How are the inserts packed?
A: Neutral cartons with anti-rust coating and separators between inserts, or customer-labelled packing where authorisation is provided.

Tell us the engine model, the quantity you need and the rebuild schedule you are working to. Our team confirms the 4N5893 valve seat insert application and replies with a quotation for the insert and any other CAT Engine Parts on your list, from 4N-2927 and 7M7219 bearings to 1609874 gasket kits and 348-2387 control modules.