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Vacuum lines z20s

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#1 Flo1993



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Posted 15 January 2018 - 12:11 PM

I cant seem to find a thread on vacuum lines for my z20s motor. So there's 2 brass lines at the front of the motor, the one on top is going in under the weber carb and the other line has no hose at all from either side. At the end by the distributor it sucks air and if I close it off the engine stalls. So my question is where does this route to on both ends? Thabk you

#2 datzenmike



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Posted 15 January 2018 - 05:24 PM

Well there were (at least) two Z20 engines used. There was an '80-'81.5 used in the HL510 and then a later Mileage Option Z20 used in the '84-'86 720. All I have is the '84 hose routing.


On the 720 Z20 there were three hard lines (steel not brass) running from under the intake down over the front of the engine and under the distributor. One was for vacuum advance on the distributor (and likely the purge on the charcoal canister if only two lines) the third one is a vacuum source to draw fumes stored in the canister into the intake to be burned.


You don't have a Hitachi carb so I guess the only ported vacuum line on the Weber just goes to the vacuum advance on the distributor and to the Purge line on the canister. The other line connects to manifold vacuum and to the vacuum fitting also on the canister. The hard lines are all the same just make sure the two ends go to the right places.

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