engine vacuum

[Thomas]

After remounting a new head on my 1,3S engine, I did some tests including a depression test with a manometer connected through a T-piece to the two connections on the intake side just before the intake ports. After stabilization, the depression is 11 inHg at idle, slightly more then before I changed the head. But internet litterature tells me that 17-19 inHg would be normal - can someone pls confirm? Note I replaced all gaskets.
Maybe the engines was not really warm yet, don't know if that can affect readings.

Incidentally I also tested directly on the barrels (I have Dellorto's) using the "Carbalancer" device, which has four columns - reads approx 24-21-25-22 but don't recall if those were inHg or mmHg. Should I be looking at retuning the butterflies?

Thanks for your help - Thomas

[SuperFab]

Check to make sure you have a good seal between the master cylinder and the servo. I had low vacuum as well. I first disconnected the vacuum hose to the servo and plugged it...ran the engine and the vacuum reading was normal. I ended up making a gasket between the master cylinder and the servo as the standard o-ring that is supposed to be there did not seal effectively. Once the gasket was in place, all is well. I was re-installing a rebuilt master cylinder at the time (which incidentally was rebuilt incorrectly by a previous owner...I have a detailed post on that exercise). Good luck. Fabio