crankcase pressure test ?????????

[DCC]

I would like some help on how to pressure test crankcase to see if seals or gaskets are leaking and what psi to presurize crankcase. dont want to create new problems. (not compression test) thanks for any help

 

[R.Johnson]

Re: crankcase pressure test ?????????

If you figure that out, let us know.

 

[SparkieBoat]

Re: crankcase pressure test ?????????

if your engine was run hot you could have messed up you pistons..specially your top ones. this will result in poor crank case pressure and you engine will not run properly..other than that it could be your reeds, as long as your compression is good and intake gaskets are ok.

 

[SparkieBoat]

Re: crankcase pressure test ?????????

only way I could see to test crank case pressure would be to fabricate a plate that would bolt over your intake manifold where your carb should go and drill and tap a hole for an air hose fitting, rotate piston to opposite TDC and pressurize, I would think 40 PSI should do the trick. I don not even know if that would work but I think it would.

 

[schematic]

Re: crankcase pressure test ?????????

Depending on engine type, this would be tricky to do. You'd be better off troubleshooting by "symptom". Even if you managed to partially seal the engine and supply air pressure, the lower crank seal isn't visible.

Even if no visual leaks were found externally, it doesn't guarantee that the gaskets/seals won't leak under vacuum.
Best to troubleshoot by symptom and idle quality.

 

[seahorse5]

Re: crankcase pressure test ?????????

there is no easy way to pressure test an outboard crankcase as each cylinder is not completely sealed off from the next one, plus the recirculation system connects all the individual crankcases.

You would have to remove the whole powerhead, fabricate block off plates, remove and plug every recirculation line, just to test the integrity of the upper and lower crankcase seal.

 

[Joe Reeves]

Re: crankcase pressure test ?????????

Just find the line/hole that operates the fuel pump. Connect a hose to it and hold your finger over the end of that hose or over the hole. Crank the engine over. That'll tell you if the crankcase pressure is okay or not.

 

[SparkieBoat]

Re: crankcase pressure test ?????????

great idea Reeves, I have learned my 1 thing for today now..thanks

 

[F_R]

Re: crankcase pressure test ?????????

That will test that one crankcase chamber only. Trouble is there is a separate one for each cylinder. They are (hopefully) isolated from each other. If they aren't, you got big trouble.