valve lashing help

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Apr 19, 2023 | 11:41 AM

discostu

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valve lashing help

dz 302 all stock expect for compression it has been dropped to 9.5 to 1. The main question is with valve lash. everything says it should be .26 cold. however vacuum at idle with this is 6ish and compression gauge reading is 125ish. now if i open up a bit to .35 vacuum jumps to 10-11 and compression to 150ish. is there any issues with running .35 vs .26?

Apr 19, 2023 | 01:47 PM

G Atsma

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From: Central Cal.

Why is this in Advanced Engineering?? Because this isn't that....

Apr 20, 2023 | 03:50 PM

IGN-1A

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Cam Lobe Design

Cam Lobes have a ramp, when the valve opens, to allow the "slack" in the Valve Train to be removed.

Apr 22, 2023 | 03:35 PM

musthaveLSx

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From: Upstate NY

Low cranking pressure due to cam valve events not matching compression ratio. IVC is too late for 9.5:1 to perform well overall. To be blunt, you can't polish a turd. This is one of the reasons why cam companies have a minimum suggested compression ratio. When you increased the valve lash, the intake valve closed earlier, thus raising the cranking pressure.