Pressure testing BR600 engine

kaliona

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Pressure testing a BR600 engine. Wondering if the way I am doing it is correct. What I did was blocked off the intake (carburetor) side, blocked off the exhaust port and left the spark plug in. I connected my pump to the impulse port and pumped up to 7psi. I found leaks along the joint at the engine pan to cylinder block which is what I suspected. Does pressure checking it through the impulse port this way only show leaks below the piston? How would I test for leaks to see if the valves are completely seating?
 

StarTech

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Yes as setup only tests cylinder and crankcase leaks but not the valves. For the valves you need to unblock the intake and exhaust ports and put engine at TDC compression stroke. Actually it would better to input the air pressure via the spark hole and have the impulse plugged. It is basically the same leak down test you use on regular 4 cycle engines just less pressure.
 

kaliona

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I set the piston at TDC and blocked the intake and exhaust ports and pressurized through the spark plug hole just to see if any air would get passed the rings. Sure enough air leaked through the impulse port and at the engine pan to cylinder block like my first test. Should air be getting passed the rings like that? Are my rings bad? Maybe the cylinder walls are scored. .. .haven't dug down that far yet.
 

StarTech

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To look scoring without the whole engine down pull the muffler and take a look. Most damage occurs on the exhaust side.
 

kaliona

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On this engine you can only see the valve stems through the exhaust or intake ports. I already have the engine out anyway so I'll just open her up and take a look. If the cylinder walls are good, does air leaking from combustion chamber to crankcase indicate bad rings? Or is it considered normal for some air to get passed rings?
 

StarTech

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Sorry forget that it is a 4 mix engine. My fault for the mis-information

Migraines does that to me
 
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ChristopherStobie

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Hello, friends, I am a big fan of such equipment, engines, tests, I always with great curiosity and utmost attention follow various analyzes, videos, such units. I read a lot of articles, all kinds of stories that you can find from the source, to learn a lot of detailed new from this topic, or read something interesting about standardized testing in the essay. I myself write a lot about similar situations, I like to talk about it on the forums, it's really interesting.
 

Hammermechanicman

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On this engine you can only see the valve stems through the exhaust or intake ports. I already have the engine out anyway so I'll just open her up and take a look. If the cylinder walls are good, does air leaking from combustion chamber to crankcase indicate bad rings? Or is it considered normal for some air to get passed rings?

Yes. It is normal for some air to get past the rings. When pressure testing a 4 mix engine after you have blocked off the intake and exhaust ports and checked for leaks at crankcase and seals and it holds pressure you unblock the intake and exhaust with the piston at TDC and valves closed and see how it now holds pressure. Valves are seldom perfect and pressure will leakdown slowly. The slower the better. If you can hear air leaking in the intake or exhaust ports you have a valve problem.
 
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