manfold vacuum help

[adyv8]

hi

I have a stock v12 lincoln

inlet manifold with gauge is 10 at idle

when revved goes down to 5

this is with the wipers disconnected

and the dist  disconnected also

don't matter which one I take the reading from

dist pipe

wiper pipe

or carb pipe

all still 10

is ten a good vacuum

can anybody help

ady

[19tom40]

A steady low reading usually means that the valve timing is off. It could also mean that the rings are bad. Take a compression test and if the readings are even and above 100 lbs, then I would take off the timing gear cover and check the valve timing. Turn the engine until #1 cylinder is on the compression stroke and then watch the timing and crank gears. The dots should line up at TDC.

 

http://www.onallcylinders.com/2015/05/08/quick-tech-how-to-read-a-vacuum-gauge-to-pinpoint-engine-problems/