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Vacuum reading

mamoose124

Gold Level Sponsor
Do any of you know what the normal vacuum reading should be for a 1725cc engine at idle? Or, where I could find this spec?
 

Mike O'D

Gold Level Sponsor
A quick internet search for generic engine vacuum indicates normal would be between 14" and 22" Hg. I asked the same question a while back and did not get a response with any actual numbers. I was hoping for " my engine runs great and I see a reading of X at idle". I feel I still need to do some tuning, but I was reading about 16" Hg.

Fergusonic - where in the manual are those numbers from?

Thanks.
 

Barry

Diamond Level Sponsor
iaw what I see in my copied manual:
5 Hg " @ 1/2* - 3*
7 Hg" @ 3* - 5*
8.25 Hg" @ 4* - 6*

workshop manual
General Data Pg 17 bottom of page



First, that information is from WSM-124 which does not apply to a 1725 engine. Second, that information shows the degrees of vacuum advance that results from different levels of manifold vacuum; not the normal vacuum reading at various RPM's.
 

beamdream

Gold Level Sponsor
Do any of you know what the normal vacuum reading should be for a 1725cc engine at idle? Or, where I could find this spec?

Typical reading for standard engines is around 22"

20 - 22" is OK , a road test is recommended to see if there's any pinging; my own experience is that 22 will give you highest idle rpm but usually you'll be right on the edge of the pinging zone.
 
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