Oil Pressure & the Spin-On Adapter
by Jack Emery, firstname.lastname@example.org
Reprinted from The Vintage Triumph, Number 49
Sudden oil pressure loss in your TR6 or TR250 may not be cause for total panic. If the car is equipped with a spin-on filter kit the problem might only be that the incorrect filter has been installed. Full flow oil filtration systems such as used by Triumph pass all of the oil from the pump through the filter before proceeding to the bearings. Any stoppage at the filter results in no oil pressure at the bearings. The original canister type filter employed a filter reilef valve inside the canister. This device ensures that in the event of a plugged filter, oil is allowed to bypass the filter. Unfiltered oil is preferable to none at all!
Filter stoppage may be from contamination or simply because the oil was too cold and thick to pass through the filter medium. In my case, 20W50 oil at 20 degrees dropped my pressure from 70 PSI to 20 PSI. As the engine warmed the pressure rose, but not fast enough to calm my nerves. Quickly checking the logical problem areas gave no clue, the plugs had not been forced from the end of the rocker shaft. Also the pin securing the gear to the oil pump drive shaft appeared intact. Removal of the large hex pressure regulating valve from the side of the block showed the spring in fine condition. With it removed a brief start of the engine produced a large puddle and confirmation that the oil pump appeared functional.
Studying the shop manuals lubrication flow chart led me to believe I had a restricted