but the cam tower mod was for the cam journals, not the lobes. These are just splash lubricated as they use roller rockers. Still should not happen today anymore.
The VTEC control is a safety linked feature and has therefore 1st order priority. Thence, once the VTEC is not engaged a greater part of the oil flow is kept away from the head. This is the fail safe setup:
- VTEC solenoid has 0 V and is closed
- VTEC pins are in unlocked position
The consequences of that is that a greater part of the oil flow through all head oil sink systems (rocker shaft, tower bearings) is reduced as the oil supply over the VTEC solenoid is closed partely. About a 10th of the pressure can be found at the non-VTEC operation at those sinks, flow is lower accordingly. Now the rocker shafts are feeded by #2 tower. What Joe did, was plugging those #2 saddle rocker oil sources and separate tower and cam lobe oiling separately over the #5 tower oil source modification. So that the tower oiling and the rocker oiling is supplied by two independed lines. VTEC is still working, while oil flow to the rockers shaft is increased massively.
So his oil modification was not only for the cam bearings, it was mainly for the rocker shaft supply, which is the basis for the cam lobe oiling. His intention was to suppress lobe wear which cam up once valve acceleration and lift increased massively by e.g. the first versions of the S2 T2 cams, which was compensated by huge valve spring forces. What really killed these lobes was the Hertzian pressure in a oil lacking system around idle. Those casted cam lobes worn down fast and did their thing on the rollers of the finger followers too.
The oil pump relief spring mod you have hit the same mark too. The increased oil pressure allows an higher oil flow under non-VTEC into the head, which is not necessary if oil temp and oil grade as well as warm up operation are done right. Of course the game changes if oil grades are increased and or or oil temps are lowered. For what ever reason some race guys (KTuned, ...) think, this would be a good idea
As I said, a bigger portion of the aftermarket misses basic engineering standards, coming up with wrong solutions for misunderstood customer issues. The lower thermostat balance temperature is a good example. They see customer ECT goes through the roof, solution start earlier big circuit cooling to raise some time until that point. Totally wrong solution if driving around is also an application. Same with the RR4 cams of 4Piston, more VE found by harder acceleration ramps and lower durations, but it comes with valve bounce in higher engine speed. Solution by 4Piston, increasing the valve pressure like NASCAR did it 30 years long. But we are not at a circle race or 1/4 mile, their customers also drive from home to track and back or even commute with it. They totally missed the fact that their valvetrain system is only proper working in VTEC for short time only. That is a totally mismatch of application and part development. An engineer would know that these two always need to be overlayed. They are still the garage guys with huge 1/4 mile experience, but not capable to transfer that knowhow to other applications as they let miss basic engineering standards.