Size of Hole MP Line

by **Ben Ayalon** » Fri Aug 08, 2008 8:31 pm

It should be 1mm or ( I think) 1/32" but check if my convertion from mm to Imperial is correct.

Ben

by **kenhill** » Mon Jun 01, 2009 9:38 pm

by **MV Case Jr** » Tue Jun 02, 2009 5:15 pm

by **kenhill** » Fri Jun 05, 2009 1:54 am

TTT
How do I assist a mechanic that responds as follows looking for proof that it came from the factory like that. Is it in the service manual???

"I can understand their logic, not sure if I agree, but I understand it, my thoughts are it can provide an air leak to that cylinder that would cause it to run lean, that’s always been what I have been taught. I reserve the right to be wrong, and am willing to pay up with lunch, provided someone comes up with a time honored decision. 1/32 is a pretty mall hole, I believe it would plug up and the next guy would replace it any how…"

by **MV Case Jr** » Fri Jun 05, 2009 3:26 am

Ken ,
according to the Wag-Aero catalog , the hole is .040 . The Manifold Pressure guage is a closed circuit . There is no outlet so no leak . What would be going through your intake system besides the fuel/air vapors that could plug it up ?? If you have a parts catalog , look at page 1 E 11 ,
Fig. 7A , part # 51 . Look it up on page 1 E 19 and it shows Piper part
# 460 682 and calls it a connector -(W/H 48 X 4 ) . That looks like the the same part as the Wag-Aero part . If you talk to any instrument shop , they will tell you that some airplanes require a restrictor and some don't .
If your needle wiggles , you probably need one IMHO . I know it worked for me .

Marty

by **kenhill** » Fri Jun 05, 2009 5:19 pm

Marty, the mechanic fabricated a new line. When I mentioned it should have a hole, his response was that a hole would feed additional air to that cyclinder thus causing a lean condition.

does the catalog show a hole in the line? My needle does not wiggle.

by **Ben Ayalon** » Mon Jun 15, 2009 4:20 pm

by **MV Case Jr** » Wed Jun 17, 2009 3:43 am

Ken ,
There is no hole in the line ( at least there shouldn't be ! ) . The hole is in the fitting the line attaches to . As I said , it's a closed circuit that dead ends at the MP guage .

Marty

by **Ben Ayalon** » Wed Jun 17, 2009 9:24 am

Marty
Can you explain please, which fitting? The Aluminium tube connects in one end to the cyl. And at the other to a rubber tube (if memory works). I don’t understand.

Thanks

Ben

by **MV Case Jr** » Thu Jun 18, 2009 3:37 am

Ben ,
The fitting works best if you install it into the intake and then attach the MP line to the fitting . You CAN install it into the back of the instrument but it won't work quite as well at damping the pressure pulses in the intake system . I have a hard ( aluminum ) line to the guage but you could have almost any kind of line as most have been changed over the years .

mARTY

by **Ben Ayalon** » Sat Jun 20, 2009 4:54 pm

Sorry Marty, I am not with you.
Install it into where in the intake?
It is fitted into the cyl. just above the intake manifold pipe. Where else can you fit it?

Ben

by **MV Case Jr** » Mon Jun 22, 2009 9:44 pm

Ben ,
Sorry for the confusion . Yes , loosen the MP line from the cyl . If there is a fitting in the Cyl. , remove it and install the Wag-Aero fitting . Reattach the MP line . If the MP line has a fitting on the end that screws directly into the cyl. , you will have to change it ( the fitting ) to one that will attach to the Wag-Aero fitting .

Marty

by **Ben Ayalon** » Tue Jun 23, 2009 7:20 pm

Thanks, now it start to make sense to me, time to look for the fitting so I can see which one will do the trick.

Ben

Size of Hole MP Line

Size of Hole MP Line

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