1994.5 - 1997 7.3L Power Stroke Diesel  

Compression Test

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  #46  
Old 11-04-2013, 09:47 PM
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I doesn't even have threads in there! Bummer
 
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Old 11-04-2013, 09:51 PM
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Originally Posted by oldbird1965
I doesn't even have threads in there! Bummer
Well.....Crap!
 
  #48  
Old 11-04-2013, 09:55 PM
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Really! I'm going to see if I can adapt one of the other pieces and make it work.
 
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Old 11-04-2013, 09:59 PM
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I can send you mine if you need it.
 
  #50  
Old 11-04-2013, 10:02 PM
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I'll let you know buddy!
 
  #51  
Old 11-05-2013, 07:52 AM
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Glenn, i'm sorry for all the trouble you're having as well - I was following your thread in the beginning as I will be doing a compression test soon, but didn't see all the check-valve issues that arose.

if you haven't sorted it out yet, one of these check valves may help and are only a day away by UPS: McMaster-Carr. I just used a 1/4" brass NPT one in adding an extra 35 gallons to my compressed air system so that I can disconnect the compressor and not lose pressure in the extra tank. I was curious how fast the valve would close, but it seems to be instantaneous at 120 psi, so i'd guess it should work well enough in a compression tester at ~300-400 psi.

not free, but it sounds like $10 would be worth it to stop the frustration at this point.
 
  #52  
Old 11-05-2013, 08:28 AM
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Thanks JP, looks good.
 
  #53  
Old 11-05-2013, 12:46 PM
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Guys, IIRC schrader valves are only rated to 250 psi. Maybe they make a high pressure version, idk. You might be stuck using a ball valve to release the pressure.
 
  #54  
Old 11-05-2013, 02:58 PM
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When i did injectors a few years ago, i had some of the same issues doing the comp test. I just had my son turn it over with the key start position, then I recorded the highest number. If i recall correctly my numbers were not as high as some thought they should be (somewhere around 325 to 375, didn't seem to bad to me most were closer to 375. The test was also done when it had not run or warmed in about 2 weeks.
 
  #55  
Old 11-05-2013, 06:17 PM
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Originally Posted by cowmilker08
Guys, IIRC schrader valves are only rated to 250 psi. Maybe they make a high pressure version, idk. You might be stuck using a ball valve to release the pressure.
The compression kit I have is the same as a lot of others on here. Lots of schrader valves in there. IDK either.

Originally Posted by richdawg
When i did injectors a few years ago, i had some of the same issues doing the comp test. I just had my son turn it over with the key start position, then I recorded the highest number. If i recall correctly my numbers were not as high as some thought they should be (somewhere around 325 to 375, didn't seem to bad to me most were closer to 375. The test was also done when it had not run or warmed in about 2 weeks.
If you only judged your results Rich on one compression stroke, then your numbers are low. I think the directions call for four compression strokes.

I got some fittings today so I now have a check valve. I didn't do the test because of 40 mph winds and I'm working outside. I didn't want dirt in the motor. I hope to do it tomorrow.
 
  #56  
Old 11-05-2013, 06:30 PM
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You need to build you a small shop in the back yard or something, just to work on your truck in
 
  #57  
Old 11-05-2013, 06:40 PM
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[QUOTE=oldbird1965;13709153]
If you only judged your results Rich on one compression stroke, then your numbers are low. I think the directions call for four compression strokes.

I don't count the number of times it turns over, I've always just cranked it till the needle doesn't go any higher. I hope I haven't been doing it wrong all these years. I did it the same as with spark plugs (take them all out)
 
  #58  
Old 11-05-2013, 06:43 PM
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That's the way I do it Rich....crank it until it doesn't build anymore pressure.
 
  #59  
Old 11-05-2013, 07:30 PM
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Originally Posted by ReBilld
You need to build you a small shop in the back yard or something, just to work on your truck in
I wish, no room here. The weather most of the time is great so I'm OK with it.

[quote=richdawg;13709263]
Originally Posted by oldbird1965
If you only judged your results Rich on one compression stroke, then your numbers are low. I think the directions call for four compression strokes.

I don't count the number of times it turns over, I've always just cranked it till the needle doesn't go any higher. I hope I haven't been doing it wrong all these years. I did it the same as with spark plugs (take them all out)
I think I misunderstood you Rich. I thought you said you had a check valve problem like I did yesterday.
 
  #60  
Old 11-05-2013, 07:51 PM
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IDK I'm getting to old to remember about the check valve most of the testers I've used in the past have had the check valve, but I am not sure now about the hacked together one i made from the HF kit. anyways It really might not matter if you have a helper crank and you watch the gauge when it stops going up just write that number down and go the the next one. sorry for any confusion i still have that dam CRS and it doesn't seem to be getting any better.
 


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