Compression Test
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Mountain Pass
Joined: Oct 2009
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Compression Test
So, acting like I was working on a gas engine I removed all the injectors to do a compression test......then did some reading and saw that you remove the glow plugs! Duh! OK, so now I am putting the injectors back in and just want to make sure I dont need to reconnect the injector lines....I plan on replacing all the injectors and getting the pump rebuilt if it passes the compression test.
Thanks,
Thanks,
Lead Driver
Joined: Oct 2003
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From: Madison, WI
I've never heard of a gas engine where you remove the injectors for a compression test....
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Mountain Pass
Joined: Oct 2009
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I was using the injector as a comparison to the spark plug.........and since you didn't answer my question, I see you are not interested in helping, just looking to be a ...........................
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Mountain Pass
Joined: Oct 2009
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I used a K-D Tools Diesel compression gauge. Had over 450 psig on every cylinder but one. And bummer, it had 220 maybe, and it took five go-rounds to get that. I put a couple tablespoons of 15-40 in and it only came up like thirty pounds. I see the head coming off and getting that one touched up. Kind of adds up since you could hear it do the "woof, woof" real loud some times in the morning. My daughter called it the death shake! I thinking of using RD-IDI to get the new pump and injectors. There was one other company that I was reading about that said they sleeve the cylinder that the advance piston functions in. This sounds like a good practice. Any suggestions on that subject?
V-465
V-465
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From: Oregon
If you have an air compressor, pull the valve covers and loosen the rockers so the valves close. Run air into the glow plug holes with a rubber tipped nozzle, and pay attention to where it gets out of that cylinder. Air out of intake is intake valve, air out of exhaust is exhaust valve, air out of crankcase is rings.
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Mountain Pass
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When I pull the rocker cover I will have a look. I am hoping for a broken spring I can just replace. All the other cylinders were up near 500 psig.
V-465
V-465
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Mountain Pass
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When I pull the rocker cover I will have a look. I am hoping for a broken spring I can just replace. All the other cylinders were up near 500 psig.
V-465
V-465
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Mountain Pass
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So I have a little more information on the low compression. I pulled the rocker cover an the third valve from the fire wall on the passenger side has a broken bolt that holds the rocker arm down. Thinking I've stuck the proverbial fat hog, I was pretty happy. Then the more I think about it....should that cause low compression? I can't process that much stuff in my brain right now. It would be quite coincidental that the cylinder with low compression also had the broken bolt and the two are unrelated. But stranger things have happened I suppose. I suppose the thing to do is put a new bolt in both the exhaust and the intake and do another compression test. I'll get a couple new bolts on Monday and run through the motions again.
V-465
V-465
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Mountain Pass
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I put an after market grade 8 bolt in just to test compression and it's back up over 420 psig. now I just need to find out why the rocker 4th from the fire wall is so loose. Bent pushrod? Lifter not pumped up?
V-465
V-465
Fleet Mechanic
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For the loose rocker, its more then likely just a lifter not pumped up but you can easily remove the push rods. Just undo the two bolts holding the rocker pair down and pull the push rods out, do keep in mind the push rods do have a copper colored end that goes on the rocker side, more then likely it wont look like copper now but that end is different from the lifter side so just make sure you put them back in the same way.
You can build full oil pressure just by cranking the engine over (remove glowplugs to make it easier on the starter) to see if the lifter is just leaked down.
You can build full oil pressure just by cranking the engine over (remove glowplugs to make it easier on the starter) to see if the lifter is just leaked down.
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parrisw
1994.5 - 1997 7.3L Power Stroke Diesel
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Nov 25, 2008 08:10 AM