It throws off the fuel-air mixture locally, only affecting a few cylinders or one side of the engine, for those engines not having spider induction tubing.
The GAMI-leantest flown at two different altitudes (say 3000ft and 6000ft) should show the same ‘pattern’ of cylinders peaking. If the pattern is different then an induction leak is to be suspected. At high manifold pressure (say close to ambient) less effect is observed from induction leaks than idling where the delta between outside pressure and low manifold pressure inside the induction tubes will amplify even a small leak.
Indeed; however my Q was why does a small gap cause such havoc?
Induction leaks are a go-to fault when any aeroplane is running like sh-it. Changing gaskets and induction hoses/rubbers are well worth your time if you are not sure of when they were last done.
To pick up an old thread, I know a case of an induction leak which really messed up the way the engine was running. All it was was a intake pipe gasket which came out.
Can anyone explain why induction leaks have such a powerful effect? There is a huge amount of suction, the air path from the air intake is a large duct, yet a tiny gap like this can really screw things up.
Thank you Peter! This is helpful.
Send the data Gami is what I think he meant. Email.
I have just heard from an engine specialist in the USA that there is a better test:
The data then requires interpretation and that bit I am not sure about but GAMI are apparently familiar with this.
OK Lucius, it’s your aeroplane and your money, find an A&P with a smoke tester.
Use of a smoke tester, these are designed to use for leaking find.
before i go flying around burning expensive gas to find
I actually not flying around burning expensive gas. This test just takes 3 minutes, and can be easily done on a routine flight.
enroll the services of a good motor mechanic
Not the best advice. You better collect as much info and data as possible, prior to handing things over to an A&P. Remember, once you enroll the services of a good mechanic the clock starts ticking, and you turn into an ATM machine. Besides, it is very difficult to judge whether a mechanic is good or not.
go with Stick’n’rudders advise
Not sure what you mean. What is a stick’n’rudders advice wrt engines?
Send it to GAMI and have them tell you, no?
Before doing this I like to collect as much info and data as possible. I.e. if I have an induction leak, it would not help sending an injector to GAMI.
