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Need help with compression test.

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Old 04-26-2010, 07:35 PM
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Need help with compression test.

I am doing a compression test on my 7.3 with 137K miles and have a strange dilemma. number two did 260 psi. 4,6, and 8 did 0psi. We thought the gauge might be bad so we went back to the first (#2) and this time got zero PSI, that was the one that got 260 the first time. We took the gauge of and just felt for air and there was no puffing or sucking through the glow plug hole.

What is going on?

We can blow air through the gauge adapter and the gauge works when we hook it to the air compressor.
 
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Old 04-26-2010, 11:09 PM
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If when you repeat the test and you come up with different results tells me you are ether not using the gauge properly, losing your air seal, or you have a bad gauge.Does the gauge have a pressure relief button? Is possible that is bad,or are pushing that when you are trying to take a reading?
 
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Old 04-27-2010, 06:39 AM
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Originally Posted by wigpescador
I am doing a compression test on my 7.3 with 137K miles and have a strange dilemma. number two did 260 psi. 4,6, and 8 did 0psi. We thought the gauge might be bad so we went back to the first (#2) and this time got zero PSI, that was the one that got 260 the first time. We took the gauge of and just felt for air and there was no puffing or sucking through the glow plug hole.

What is going on?

We can blow air through the gauge adapter and the gauge works when we hook it to the air compressor.
That sounds like big trouble with the engine.
When you pulled the glow plugs, did the tips come out still attached to the glow plugs?
 
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Old 04-30-2010, 10:52 PM
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I figured it out. I did not have the right adapter for my compression tester so we gutted and injector braised on some pipe and a piece of another adapter and screwed it into the whole. To get it in the whole I had to take the intake rockers off and then put them back on to do the test. I put the rods in wrong which pressed the valves down. When I cranked the engine the pistons hit the valves, bending the valves and the rods. That is why I got Zero on all of them. We spent the last 12 hours pulling the engine and now we have it sitting on the floor with the head off. Number six had a ring disintegrate and is all chewed up. The piston is covered in dents and the head even has some dents in it. The cylinder walls are gouged pretty bad as well.

So here is my new dilemma, should I hone out that cylinder, re ring it and throw it back together with new valves and rods or should I do a complete rebuild? Can I by just one set of rings and one new piston?

What is a good price for a machine shop to re bore all eight holes? What is a good price for a rebuild kit?

Does any one have the tolerance specs for the rings and the crank bushings?

Are there any rip off rebuild kits that I need to watch out for? What normally comes in a kit, I read in another post that the "Ford rebuilt kit Rocks" but I am not sure if that means it is superior to other kits or if it is just available and good.
 
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Old 04-30-2010, 10:54 PM
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The first time I pulled the glow plugs, one of them had the tip broken off and the guts came right out the top. I think it came out of number six.
 
  #6  
Old 05-01-2010, 01:43 AM
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Originally Posted by wigpescador
I figured it out. I did not have the right adapter for my compression tester so we gutted and injector braised on some pipe and a piece of another adapter and screwed it into the whole. To get it in the whole I had to take the intake rockers off and then put them back on to do the test. I put the rods in wrong which pressed the valves down. When I cranked the engine the pistons hit the valves, bending the valves and the rods. That is why I got Zero on all of them. We spent the last 12 hours pulling the engine and now we have it sitting on the floor with the head off. Number six had a ring disintegrate and is all chewed up. The piston is covered in dents and the head even has some dents in it. The cylinder walls are gouged pretty bad as well.

So here is my new dilemma, should I hone out that cylinder, re ring it and throw it back together with new valves and rods or should I do a complete rebuild? Can I by just one set of rings and one new piston?

What is a good price for a machine shop to re bore all eight holes? What is a good price for a rebuild kit?

Does any one have the tolerance specs for the rings and the crank bushings?

Are there any rip off rebuild kits that I need to watch out for? What normally comes in a kit, I read in another post that the "Ford rebuilt kit Rocks" but I am not sure if that means it is superior to other kits or if it is just available and good.
Now this is a good example of having a bad day!!!
 
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