What was found
ENGINE NR 3 AND 4 OVER PRESSURE LIGHTS ILLUMINATED AFTER BRAKE RELEASE DURING TAKEOFF ROLL. RTO PERFORMED. CONFERRED WITH MX AFTER LIGHTS EXTINGUISHED AND CONTINUED FLIGHT. NOTED BY MX NO REJECTED T/O INSPECTION REQUIRED DUE TO ZERO AIRSPEED AND MINIMAL BRAKING. PERFORMED THE NECESSARY TROUBLESHOOTING TO ISOLATE NR 3 AND NR 4 ENGINE OVERPRESSURE LIGHT ILLUMINATING AT TAKEOFF POWER. NO FAULT FOUND PER WDM 36-3-2. REMOVED AND REPLACED NR 4 BLEED AIR REGULATOR VALVE PER DC-8 M/M 36-12-1. OPS CHECKED SERVICEABLE PER JRH 12.2 OF NR 3 AND 4 ENGINE.