* Manufacturing tolerances: Slight variations in manufacturing processes are normal. A 1/16th inch difference might fall within acceptable tolerances for the manufacturer, especially if it doesn't significantly affect lifter function. However, this is less likely to be consistent across multiple replacements.
* Different part numbers/revisions: The engine might have had revised parts over its production run. The replacement lifters might be for a later revision of the engine, even if outwardly the engine appears the same. Manufacturers sometimes make slight design changes that result in dimensional differences.
* Incorrect part supplied: This is a significant possibility. The most likely explanation is that the wrong lifters were supplied. Double-check the part number against the engine specifications to confirm compatibility. A seemingly small difference like 1/16th of an inch can be disastrous for valve train operation.
* Wear and deformation: The original lifters might have worn down or deformed over time, making them appear longer than the new ones. This is less likely to be a consistent 1/16th of an inch difference across all lifters, though.
* Aftermarket parts: If the replacement lifters are from an aftermarket supplier (not the original equipment manufacturer), the tolerances and specifications might be slightly different. Quality can vary significantly between aftermarket suppliers.
Before installing any replacement lifters:
* Verify the part number: Absolutely confirm the part number matches the specification for your specific engine. Use a reliable parts catalog (like a dealer's online parts catalog) to avoid mismatches.
* Compare dimensions carefully: Measure the original lifters and the replacements meticulously to confirm the difference and whether it's consistent across all lifters. A single lifter being slightly different is less concerning than all of them being shorter.
* Consult a mechanic: If you're unsure, seeking advice from a qualified mechanic is crucial. A 1/16th inch difference *could* be insignificant or it could cause serious engine damage. It's better to be safe than sorry.
In short, the difference is highly suspect and warrants careful investigation before installation to prevent engine damage.
