O.S. Engine OS4A407040 Pulse Spacer GGT10 engine spacer  [OS4A407040]

Pulse spacer for nitro engines

This O.S. Engine pulse spacer is an RC-scale engine accessory designed to sit between the engine mounting or exhaust interface and the rest of the exhaust/manifold assembly. It is intended for fine mechanical tuning of pulse characteristics on glow or nitro model engines, helping to change how pressure waves interact with the exhaust and intake on small-displacement R/C engines.

Installation is straightforward for hobbyists familiar with engine mounting: the spacer is placed at the exhaust or mounting flange, secured using the existing engine hardware, and checked for alignment and sealing. No special tools are required beyond the standard hex driver set used for engine mounting hardware, but always verify flange fit and gasket condition before final tightening.

Functionally, a pulse spacer modifies the timing and strength of pressure pulses arriving at the exhaust and intake interfaces, which can affect throttle response and the tuning window for the engine. Use it as part of incremental tuning: change one variable at a time and record results so you can evaluate its real impact on your model's performance.