how to check for manifold leaks

1

1929tudor

Senior Member
Not sure if I have a manifold leak but I remember reading a while back maybe on the old Fordbarn how to check for manifold leaks both intake and exhaust on the outside. I can't remembr though what was done. Was it spray a little WD 40 or take a spray bottle of water and listen till the engine changes speed. Maybe it was even something different than that. Any help on refeshing my memory. Thanks alot.
 
i use starting fluid for intake leaks . normally you can hear or see an exhaust leak ...... steve
 
I use a shop vac with the hose connected up to the "blower" side of the shop vac. For exhaust leaks connect the hose to the tail pipe and turn on the vac (blower). Spray soapy water and look for bubbles. For intake leaks connect the vac (blower) to the intake of the carburetor.

Bob
 
WD40 makes a mess. Starting fluid will take off paint and is far more flamable than gasoline so be careful.

I never tried Bob's shop vacuum trick but it sounds like it would work. Im going to give it a try. You don't even have to start the engine to do it.

What ever method you use, it is easier to find leaks without the fan turning and blowing air over the "test area. Take off the belt while checkiing. It may save your head or a hand too.

Ford discontinued the glan rings for only a very shoirt time in 1930 and then put them back in. There was a reason and if they fit, I use them.

Just recently I started using the copper gaskets with the round loops and they seem to seal better than all the others I've used.

Richard
Anaheim CA
 
Pictures

Here are a couple of pictures of a exhaust leaks found using the output of a shop vac and soapy water. One leak is at the flange between the manifold and the muffler. The other is at the gasket between the manifold and the engine.

Bob
 

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Bob, if you use the shop vac method, does it blow back up any rust from the exhaust pipe or muffler back into the engine? Just thinking.
 
1929tudor said:
Bob, if you use the shop vac method, does it blow back up any rust from the exhaust pipe or muffler back into the engine? Just thinking.
Click to expand...

Not really a problem unless there is a HUGE leak. The amount of air moving through the muffler is quite small. In fact if there are no leaks the air does not flow at all once the pressure builds. If there is a leak the amount of air movement is only the amount that can escape through the leak.


Bob
 
Soapy water, safer.
Attach tach and see if idle increases when sprayed. Just like in other post look for bubbles.
 
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