Model: YC4108
Part Number: B8800-1004001
Brands: Yuchai
Engine Model: YC4108
Engine Type: Diesel
Scope of application: light and medium trucks, agricultural machinery, generator sets, marine auxiliary
The Yuchai YC4108 is a four-cylinder diesel used in trucks, agricultural machinery and generator sets. Part B8800-1004001 is the piston for this engine, transferring combustion pressure to the rod and conducting heat into the rings and liner.
The YC4108 is a simple, robust design, and its pistons are correspondingly straightforward. That does not make the details unimportant: bowl shape, ring groove width and pin bore clearance all decide how the engine runs and how long it lasts.
The piston fits YC4108 engines across their ratings. Confirm the engine plate and the old piston number before ordering. Yuchai built the 4108 in several variants with different compression ratios, and pistons are not interchangeable between them.
Pistons ship wrapped and protected. Complete assemblies with rings fitted are available on request.
Clearance is measured at the skirt, at right angles to the pin, with the piston at room temperature. Too little seizes the piston when hot; too much rattles at cold start. Both are avoidable by measuring rather than assuming.
Yuchai engines often work in dusty conditions. Dust that reaches the cylinder acts as an abrasive between the rings and the bore, wearing both quickly. The air filter and intake hoses deserve as much attention as the oil on these engines.
Match the part number, the engine rating and the bowl shape. Send a photo of the old piston crown alongside the engine plate and we will confirm the variant before shipping.
Run at varying load after the rebuild, increasing gradually, and change oil early. A gentle break-in that never loads the engine is as harmful as abuse, because the bores glaze and the rings never seal.
Correct injection timing, clean fuel and adequate cooling keep pistons alive. Replace fuel filters at interval and fix overheating promptly, because crown temperature rises quickly when coolant flow drops.
Before fitting a new piston, or before refitting an old one with new rings, inspect the ring lands. A land that has been hammered by a broken ring shows a stepped surface, and rings will not seal against it. Carbon packed in the groove corner prevents the ring from seating, so clean the groove properly rather than scraping the surface.
Measure groove width with a feeler gauge and the old ring. If the groove has opened beyond specification, the piston must be replaced regardless of how good the bore looks.
Keep the pin with its piston. Circlips must seat fully in their grooves; a clip that is not seated will come out under load and score the bore within minutes of running. Fit the clips with the correct pliers rather than improvising with a screwdriver.
Where the engine is fitted with piston cooling jets, check each jet for flow before the pistons go in. A blocked jet overheats the crown and can melt the bowl edge within a few hundred hours. The jet is a small part that is easy to overlook and expensive to ignore.
Also confirm that the oil pump is delivering correctly. A pump that holds pressure but has lost volume still allows crown temperatures to climb, and the damage appears as a piston failure rather than as low oil pressure.
Pistons and rings are matched through the groove dimensions and the ring tension. Ordering a piston without specifying the ring set risks a combination that fits but does not seal. Give us the piston part number and we will supply the rings that match the YC4108 bore and rating.
Where the engine has already been rebored, tell us the oversize before the order is placed. A standard ring set in an oversize bore has excessive end gaps and will not control blow-by, no matter how carefully it is assembled.
Keep the piston in its packaging until the liner is clean and ready. Store it upright rather than stacked on its crown, and keep the pin and circlips with the piston they belong to. A dropped piston can be distorted without showing any visible mark.
It is supplied bare by default. Complete assemblies are available.
Yes, within one engine.
Yes, if the liner and the rest of the set are undamaged.
Over-fuelling, incorrect timing or blocked cooling.
Browse the Yuchai piston and components category, and pair the piston with the YC4108 piston ring D30-1004016 or the YC4108 connecting rod A8300-1004200.
Yuchai YC4108 Piston (1004001). Heat and pressure both arrive at this component first. The ring grooves control oil and compression, and the bowl decides how efficiently the fuel burns.
Check the ring groove width with the old ring and a feeler gauge. An opened groove lets the new ring flutter, and a fluttering ring breaks.
Numbers beginning 1004 are numeric-series numbers used on later WP7 and WP8 production, where mounting detail changed without a change of nominal type. On this engine, confirm the YC4108 application against the engine plate before ordering.
Check piston-to-bore clearance and ring end gaps in the actual bore. Measuring in a spare liner gives a false reading and is a common cause of oil use after a rebuild.
Ordering note. Photographs of the actual unit can be sent before dispatch on request. That is the cheapest way to avoid a return when a casting revision is in doubt.
Related reading: Piston Ring Selection: Gap, Tension and Bore Condition
| We Are 30 Years Diesel Engine Parts Supplier | |
| Brand | EPID |
| Warranty | 12 Months |
| Condition | 100%New |
| More Models | Weichai: YC4108, and other Weichai series. |
| Shipping | By sea / air / express (DHL, FEDEX, TNT, UPS, EMS) |
| Packing | Standard exporting packing or as required |
| Payment Term | L/C, T/T, Western Union, Trade Assurance |
| Delivery Time | 3-7 days (depend on order) |
| Selling Point | 1. On-time Delivery 2. Genuine Quality Assurance 3. Professional Supplier |
Pistons ship wrapped and protected. Complete assemblies with rings fitted are available on request.
Clearance is measured at the skirt, at right angles to the pin, with the piston at room temperature. Too little seizes the piston when hot; too much rattles at cold start. Both are avoidable by measuring rather than assuming.
Yuchai engines often work in dusty conditions. Dust that reaches the cylinder acts as an abrasive between the rings and the bore, wearing both quickly. The air filter and intake hoses deserve as much attention as the oil on these engines.
Match the part number, the engine rating and the bowl shape. Send a photo of the old piston crown alongside the engine plate and we will confirm the variant before shipping.
Run at varying load after the rebuild, increasing gradually, and change oil early. A gentle break-in that never loads the engine is as harmful as abuse, because the bores glaze and the rings never seal.
Correct injection timing, clean fuel and adequate cooling keep pistons alive. Replace fuel filters at interval and fix overheating promptly, because crown temperature rises quickly when coolant flow drops.
Before fitting a new piston, or before refitting an old one with new rings, inspect the ring lands. A land that has been hammered by a broken ring shows a stepped surface, and rings will not seal against it. Carbon packed in the groove corner prevents the ring from seating, so clean the groove properly rather than scraping the surface.
Measure groove width with a feeler gauge and the old ring. If the groove has opened beyond specification, the piston must be replaced regardless of how good the bore looks.
Keep the pin with its piston. Circlips must seat fully in their grooves; a clip that is not seated will come out under load and score the bore within minutes of running. Fit the clips with the correct pliers rather than improvising with a screwdriver.
Where the engine is fitted with piston cooling jets, check each jet for flow before the pistons go in. A blocked jet overheats the crown and can melt the bowl edge within a few hundred hours. The jet is a small part that is easy to overlook and expensive to ignore.
Also confirm that the oil pump is delivering correctly. A pump that holds pressure but has lost volume still allows crown temperatures to climb, and the damage appears as a piston failure rather than as low oil pressure.
Pistons and rings are matched through the groove dimensions and the ring tension. Ordering a piston without specifying the ring set risks a combination that fits but does not seal. Give us the piston part number and we will supply the rings that match the YC4108 bore and rating.
Where the engine has already been rebored, tell us the oversize before the order is placed. A standard ring set in an oversize bore has excessive end gaps and will not control blow-by, no matter how carefully it is assembled.
Keep the piston in its packaging until the liner is clean and ready. Store it upright rather than stacked on its crown, and keep the pin and circlips with the piston they belong to. A dropped piston can be distorted without showing any visible mark.
Browse the Yuchai piston and components category, and pair the piston with the YC4108 piston ring D30-1004016 or the YC4108 connecting rod A8300-1004200.
It is supplied bare by default. Complete assemblies are available.
Yes, within one engine.
Yes, if the liner and the rest of the set are undamaged.
Over-fuelling, incorrect timing or blocked cooling.
EPID supplies diesel engine parts for Weichai, Baudouin, Yuchai, Caterpillar, Sinotruk, FAW Xichai and Cummins engines. Every order is checked against the original part number before packing. Ask for a quotation with your model and quantity and we will reply within one working day.
