429 valves and rockers question

[Matti R]

I got new pump gears and the spring for regulating valve. Old spring was below spec already. Quite remarkable difference in free length! That could have caused low oil pressure, I assume.

[The Tassie Devil(le)]

What I have done in the past to improve the oil pressure is to place a washer, or two, at the outer end of the spring, which applies more pressure to the relief valve.   Worked every time, and never had a problem.

Bruce.

[russ austin]

What I have done in the past to improve the oil pressure is to place a washer, or two, at the outer end of the spring, which applies more pressure to the relief valve.   Worked every time, and never had a problem.

Bruce.

That only raises the higher RPM oil pressure, not the idle pressure.

[Jason Edge]

That only raises the higher RPM oil pressure, not the idle pressure.

Russ is correct. The relief valve sets a max oil pressure, and really has nothing to do with controlling idle or minimum oil pressure. From the factory, when the oil pressure reaches 30 to 35 psi on the 64 429, it overcomes the pressure of the relief valve spring and pushes the valve piston inward allowing the oil to exit a bypass channel. As pressure eases back, the spring again pushes back piston in the channel and closes the bypass channel.

If the relief valve gets stuck open you will see very low oil pressure as it is allowed to bleed off. If it is stuck closed you will develop very high oil pressure and you will see oil filter and other seals damaged (ie. oil leaking out!).   My experience has been  you will see them stuck open more than closed. This often happens if the front cover and oil pump assembly has been replaced and was not cleaned thoroughly leaving debris behind in the channel the valve piston moves back and forth.

I will also say having looked at over 4 dozen 429 front covers, this particular cavity seems fine.

One final comment, would be you can pick up an oil pressure guage and pop in the back of the engine where the oil pressure sending unit to the dummy light goes and get some exact readings.

[The Tassie Devil(le)]

That only raises the higher RPM oil pressure, not the idle pressure.

I fully realise that, and one doesn't go too thick with the washers.

Bruce.

[rajeevx7]

2.  Lack of zinc in modern motor oil caused premature wear of a high pressure contact part.

This this this! It's an additive, use it.

[dadscad]

The oil pump cover usually has a circular wear pattern from the pump gears. If so, they should be removed by resurfacing the cover.

[Matti R]

Finally I am priming the engine. I replaced 4 rockers and oil comes out only from those new ones when priming. I noticed that the new rockers have an oil groove inside helping oil to move to top of rocker arm. In old rockers the oil goes between the shaft and rocker but almost nothing comes to top of rocker arm. I think I will replace rest of the rockers to new design. New rocker closer to camera.