Checking A block for leak

[montidale]

After finding a lot of sludge in the crank case of the '46 A I want to make sure the water in the case is from rain and not engine coolant. So I bolted the head back on the block using the old head gasket. Made up some plates and gaskets for the coolant inlet and outlets. Filled it up with water. Then put in about 8 lb. of air pressure in the engine. After letting it sit for a few hours there is no water leaking in the cylinders or head. So I'm thinking the water in the crank case came from rain water. I don't suppose there was an easier way of checking for leaks. So now I plan on honing the cylinders and replacing the rings. The cylinders are bored out to .125 over. I still have to replace the in/ex manifold studs and deal with bearings. But I'm really encouraged that the engine can be saved.

 

[Determined]

Did about the same test on a 4 cylinder GM inboard boat engine last summer.
Let it sit with 15 psi on it for 24 hours and it did not show any change.

Two hours on the lake once everything was warm and expanded it had about 2 quarts of water in the oil pan.

I am not saying you will have the same results just pointing out that testing it cold will not always prove up a leak.

 

[Resting Relics 1]

I had the same thought as Determined. Once the engine is warmed up some minute crack may open up. before you take it apart just for giggles try using some boiling water or heat the block and head carefully with a small torch too heat the assembly and then let it sit for awhile. See what happens. Good Luck!
John

 

[Carls70]

Not a 3.0L by any chance? 😆

Carl

 

[montidale]

Determined , I bet that wasn't a cheap repair. I had the same thought about a crack showing up after the engine got hot. I pored hot tap water into the block. By the time it was pressurized the block
was back to room temp. I guess at some point I just have to put it together and and cross my fingers and see what happens.

 

[Determined]

(quoted from post at 08:54:20 02/13/21) Not a 3.0L by any chance? 😆

Carl

Yes OMC 3.0l.

Neighbor brought it over for me to re-seal the upper gearcase and a general service.

Drained almost a gallon of water from the oil pan, obviously not a good thing to find.

After doing pressure tests on it without being able to find the source of the leak I ran it for over half an hour in the water tank, it was not taking on any water so he took it out to try it.

Just put the engine on the stand last week, will tear into it as soon as this weather improves.

Fortunately he has another engine with 1 broken piston but a good block that I should be able to salvage.

 

[forty40]

Have pressure tested JD power block using 50 psi, layer assembly on its side, sprayed inside bores and entire outside with soapy solution, looking for bubbles