Author Topic: weak 451  (Read 1680 times)

Offline Hot_Rodder

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Re: weak 451
« Reply #15 on: January 24, 2007 - 04:02:44 PM »
Hot, I see your point. But what I was getting at is, you are looking at a loss over time. That's not a steady amount. And I dont know any that will hold pressure when the engine is motionless. That's not what rings are meant to seal against. So you are seeing a drop in PSI over say 10 seconds from the cylinder. But really, it would leak then anyway. All you can say is whether or not it's leaking faster or slower, and there's no baseline to compare to. A true leak down gives you a baseline, and a reading of the amount of loss. That ratio becomes the percentage leaking. As an example, lets say a cylinder pumps 150psi, then you pull the gage's valve, and watch it. It then pumps say 150, and in 10 seconds, it drops to 20psi. That's 130psi/10sec. What is bad about it? More important, what is good about it? If they all do it, you know they are all in the same boat..but is that good or bad? Using that same cylinder: You plug in the air line, and set the main gage to 100psi line presssure. the gage that is reading the cylinder reads 90psi. You know that cylinder leaks 10%. The next cylinder is done. It shows 100psi and 60psi. You know it has 40% leakage. Think of it as reading a tire tread as opposed to sticking it on an alignment rack. You know it's bad, but it cant tell you why until you get the right equipment. You're test is the right track, just not quite there.

You're test is the right track, just not quite there. :grinyes: I hear ya. Like I said, that's what we had, guess we must have guessed  ??? Correctly then.... Anyway, it wasn't up to me what tools were bought for the shop, I just worked there... ::)