Original BMW Timing Chain Slide Rail for BMW 318i, 318is, and 318ti M42 (1991–1995)

On the M42 four-cylinder in the BMW 318i, 318is, and 318ti, this Original BMW timing chain slide rail guides the chain between the crankshaft and camshaft sprockets and limits how far it can move. A timing chain rail keeps the chain on its path so the valves open and close in step with the crankshaft, and it works alongside the tensioner to control chain slack. BMW lists the part under the name Slide rail, weighs it at 65 grams, and sells it as a single piece. This rail is made in Germany. When a guide wears or breaks, a loose chain can rattle or clatter against nearby parts, most noticeably at startup or idle. Severe wear can let the chain slip, throwing off cam timing and causing misfires, stalling, or hard starting.

Original BMW Parts carry a 24-month parts warranty.

BMW has supplied this number since September 1989 with no superseding part shown, so the same rail covers the E30 cars and the later E36 318ti. Confirm the part number against your engine before ordering.

Technical Details

• Manufacturer: BMW, genuine factory part
• Part number: 11-31-1-721-641
• BMW part name: Slide rail
• Engine: M42 four-cylinder
• Weight: 65 g (0.1 lb)
• Sold as one piece
• Production start: September 1989
• Made in Germany
• Warranty: 24 months on Original BMW Parts

Common Questions

What does a worn slide rail sound like?
The usual sign is a rattling or clattering noise from the engine, strongest at startup or idle, caused by the chain striking nearby components.

Does this rail fit the 318ti?
Yes. BMW includes the E36 318ti with the M42 engine for this number, and it fits the 1995 318ti in our fitment data.

Factory M42 timing parts are part of the BMW range PMB carries for E30 and E36 owners.

Fitment & Compatibility

Use the fitment table below to confirm year, model, submodel, and application notes before ordering. With over 20 years of parts and fitment experience, PMB Performance can match this to your VIN.