leak test results

[wayman999]

I just did a compression test and found my #4 cylinder only had 50 psi so i injected air into the piston 40 psi it leaked strait out of the stern drive without any resistance does anyone know what this means .
the engine was running ok during high rpm"s but would stall out when i slowed down . There is no sign of water in the engine or oil . thank you

 

[NoKlu]

Re: leak test results

The only way to know whats going on is to pull the head.

 

[Don S]

Re: leak test results

Well, IF you had it on #4 TDC on the compression stroke, it means the exhaust valve is leaking.
If you didn't have it on #4 TDC on the compression stroke, It means nothing.

 

[wayman999]

Re: leak test results

thanks for the reply , i do not think the air is supposed to come out there was hoping some one could tell me possible reasons it would .
Unfortunately i crushed my finger in a machine at work and will not be able to do any engine dismantling until the bone knits . I an doing repairs in my head and seeing if i can obtain parts i may need its a 1973 volvo aq130 engine

 

[wayman999]

Re: leak test results

thanks for the reply Don S. I did the test last weekend I know i turned the engine around with the air preasure in it herd a little leaking in the valve cover
when the valves were opening and closeing but i dont remember if I checked the stern drive .I will try the test over this weekend and check . Pretty sure the valves are in pretty rough shape I was just worried about a cracked block under the water jacket thanks again

 

[Bifflefan]

Re: leak test results

thanks for the reply , i do not think the air is supposed to come out there was hoping some one could tell me possible reasons it would .
Unfortunately i crushed my finger in a machine at work and will not be able to do any engine dismantling until the bone knits . I an doing repairs in my head and seeing if i can obtain parts i may need its a 1973 volvo aq130 engine

Did you have it on TDC compression stroke when you did the leak down?
If you did then you have burn exhaust valve. if not then you did it wrong and the results dont mean anything.

 

[PiratePast40]

Re: leak test results

If it comes to an engine rebuild, or even just a valve job, PLEASE let the rest of us know where you find the parts. It's a Volvo B20 block but as far as I know, the cam has more overlap (either a "C" or "F" grind), the valve springs are stiffer, the valve stems are slightly longer and the timing gear set is metal instead of fiber.

There are some of us that still have the old "iron horses" and may need to do the same thing in the future.

Thanks

 

[wayman999]

Re: leak test results

will do piratpast40

 

[PiratePast40]

Re: leak test results

Sorry to hear about the finger. Hope it heals ok and the drugs are good while you're getting better .