[HWYSTR455]

Originally Posted by grivera

Ok - so yesterday I checked things out and the noise is definitely from the passenger side. While I was in there I tried Cliff’s method - went through the firing order for intake and exhaust. Bottomed out each lifter and then backed out one full turn. It still ticks at 800 rpm idle. It doesn’t tick at highway idle so I assume they are pumping up with more RPM. Oil pressure at hot idle is 30, cruising RPM is 60 psi, high idle cold is ~70 psi. Oil is 10W30.

It also occurred to me - over a month ago I did a compression test (cold) on this engine and then a leak down test (hot). The compression on #6 cylinder was 175 psi and all others were 150- 155 psi. The engine has 9.3 compression.

Here are the leak-down test results done with engine at full temperature, all plugs out and each cylinder tested at TDC. Left hand gauge at 90 PSI

1 = 86 psi
8= 84 psi
4= 85 psi
3= 85 psi
6= 84 psi (this is the cylinder with high compression)
5= 85 psi
7= 84 psi
2 = 84 psi

Could the higher compression reading on #6 be the result of the lifter(s) bleeding down on low rpm and not opening the valves enough- and therefore not releasing cylinder pressure at the same rate as the others?

Some videos of idle RPM vs high idle during cold start-up. Ignore the loose PS pump belt…

Idle RPM: https://youtu.be/G47H3BL1s_U

Hi idle: https://youtu.be/nko8XB4-nqc

How high is your 'hi idle'? No tick there that I can tell by the vid.

Just run the idle slightly higher, maybe try going 50 RPM at a time, see where it stops ticking, and check oil psi. If it's under 1000 RPM you're fine. If you're intent is to run X RPM, then note the oil psi at the ROM it stops ticking, and step up oil thickness until you reach the psi it stops ticking at for your desired RPM.

My 535 will tick if I run under 925 RPM, so, I just run it at 925 RPM. Most 'performance' cams like a slightly higher RPM than stock anyway.

Once you move away from a 'stock' or 'factory' configuration, you can't expect to run a stock/factory idle RPM. With a 'performance' cam, and a higher than stock idle RPM, the transition is easier to tune as well.


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