If you have a reground cam you will need lifter (HLA) spacers as the reground cam has had material removed from it making it a lesser diameter than stock.
If the HLAs can be compressed by hand it isn't primed with oil usually due to blockage in the oil port which on these motors is the smallest oil orifice in the motor and easily blocked. Had it happen to 4 HLAs at once with just a little gasket maker material, one other main cause of this is if the cam bearing surfaces are worn you wont get good oil pressure at the top causing HLA's to chatter badly because they can't get enough oil to pump up. Sounds horrible too.
91' MX6 DX with MS2 DIYPNP ECU, Garret TBO-335, SCG-1, 2.5" exhaust, Tial Sport MV-S 38mm WG, no cat, etc. Bosch 4-hole injectors, 2.5" Aluminum intake piping, 25"x19"x3" intercooler, ACT St Perf HD PP and Disc, AEM X-series Wideband, AEM water Methanol Injection, 17" MB Alpina Black Wheels, 225/45 GT Road Hugger Ultras, '06 Mazda 6 Front Brakes, '93 Probe rear calipers on '89 Probe discs, GT Head/fog lights, Hikari LED lamps, Logic AC/Heat controls, Clifford alarm and remote start