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Author Topic: Compression test gone very f*****g bad  (Read 1396 times)

Offline Twisty

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Compression test gone very f*****g bad
« on: May 16, 2015, 04:19:12 PM »
Ran a compression test on my 7.3.  Had a few small issues, but got it done.  I saw a video youtube of a Ford tech doing a running compression test to see how the engine performs while running.  The pressure is well below spec of the gauge/fittings/hose.  On cylinder #5, the schrader valve let go and sent pieces into the cylinder while it was running!  The gauge was only at 450psi.  Tried sucking the pieces out through the glow plug hole with no luck.  Took the exhaust apart and it's not in there.  Trying to pull the injectors now to get a more direct path to the pieces (if they are still in there). 

Likely scenarios:

1.) The pieces made their way out harmlessly
2.) The pieces made their way out and damaged the valves and/or cylinder bore.
3.) The pieces are still in there and have damaged the valves and/or cylinder bore
4.) The pieces are still in there and no harm has been done.

fml.

Maybe it's time for the 12v swap I've been lusting over.  :o
« Last Edit: May 16, 2015, 04:23:01 PM by Twisty »
88 MJ buggy, 4.0/AW4, 203/205, 3 link front/4 link rear on airshocks, 42" Iroks, full hydro

"Only wealthy men can afford to buy cheap things."

Offline Twisty

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Re: Compression test gone very f*****g bad
« Reply #1 on: May 16, 2015, 06:15:31 PM »
Looks like the best option is to buy an inspection camera.  The hole I'm able to access the cylinder through is a tap larger than .250.  The 5.5mm probe cameras will probably be my best option.

Thanks for the chat, Jerry!!
88 MJ buggy, 4.0/AW4, 203/205, 3 link front/4 link rear on airshocks, 42" Iroks, full hydro

"Only wealthy men can afford to buy cheap things."

Offline Twisty

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Re: Compression test gone very f*****g bad
« Reply #2 on: May 16, 2015, 06:33:46 PM »
This actually brightened my day.  This guy dropped a hose clamp and had to pull the engine to find it. 

http://www.powerstroke.org/forum/94-98-7-3l-general-powerstroke-discussion/243453-dropped-hose-clamp-my-7-3-block-oops.html
88 MJ buggy, 4.0/AW4, 203/205, 3 link front/4 link rear on airshocks, 42" Iroks, full hydro

"Only wealthy men can afford to buy cheap things."

Offline Axle

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Re: Compression test gone very f*****g bad
« Reply #3 on: May 16, 2015, 07:39:08 PM »
whattt! good luck Tim
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Offline Twisty

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Re: Compression test gone very f*****g bad
« Reply #4 on: May 16, 2015, 08:15:58 PM »


This is what I have.  I'm missing the rest of it. 
88 MJ buggy, 4.0/AW4, 203/205, 3 link front/4 link rear on airshocks, 42" Iroks, full hydro

"Only wealthy men can afford to buy cheap things."

Offline Ian

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Re: Compression test gone very f*****g bad
« Reply #5 on: May 17, 2015, 09:14:10 AM »
do you think you got enough of it to not have a problem?
i am an AMSOIL dealer! pm me for a quote

60 w/ minor bling 4.56, 14b ff rear w/detriot 4.56, atlas 2speed 5.0 4 custom link rear and 3link front, 110" wheelbase, pcs full hydro, fox 2.5's,  and 42" Irok stikies... and no clue

'00 tj (see above)

Offline HEYzipupyourfly

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Re: Compression test gone very f*****g bad
« Reply #6 on: May 17, 2015, 09:32:24 AM »
that really sucks, we got a nice borescope on amazon for around $60. it plugs into the laptop or tablet with usb and it works better than the snapon one we wasted hundreds of dollars on. I forget the name of it.
it would easily fit into a 1/4" hole
I once read in a bathroom stall, "You can't rush perfection"

Offline Twisty

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Re: Compression test gone very f*****g bad
« Reply #7 on: May 19, 2015, 01:12:33 PM »
Camera has been ordered and is supposed to be here Friday or Saturday. 

http://www.amazon.com/Autel-MV400-5-5-Digital-Videoscope-Screen/dp/B0091DJY8Q/ref=sr_1_1?ie=UTF8&qid=1432059054&sr=8-1&keywords=mv+400+5.5


I also called the company and spoke with 2 people in the diesel department.  The first was Jim who referred me to Bruce.  I spoke with Bruce on the phone for about 20 minutes and explained my problem.  We also exchanged some emails which I will share below.

Quote
Hi Tim,

 

I was talking with Jim. He will send you some replacement Schrader valves.

We were talking about the failure , and thinking about causes. Iím wondering if you might have pushed the deflator valve on the gauge while the engine was running?

 

Thank you, Bruce


Quote
Bruce-

Yes, actually I did.  I wanted to see how well the cylinder was building pressure.  I guess this is the pressure leak you were saying could cause the problem.  This never occured to me during our conversation.  The failure happened when the gauge was at a stable, maximum pressure.  It did not happen while pressure was building.

-Tim


Quote
Hi Tim,

 

Right, you never want to push the deflator while the engine is turning over, cranking or running. We even have a note in step 7 to wait 30 second after the engine stops rotating before releasing the pressure. This allows cylinder pressure to drop so that when the deflator is depressed you are only releasing pressure in the hose, and there is relatively little flow across the Schrader. Iím thinking about revising that note to make it clearer.

I looked up the specification on the Schrader. It can only handle a maximum of 4.3 cubic feet of flow per minute at 100 psi. Like I said on the phone, most failures with Schrader valves have to do with exciding the flow rate. They can take a lot of pressure, but at a low flow.

 

Thank you,

Bruce



Quote
Bruce-

Well, I guess we have found the cause of the problem.  I never received any kind of instruction book with my kit (that's not to say I would have even read it).  I ordered it from JB Tool Sales through Amazon.  It was actually marketed as a Star Products item with the TU-15-53 part number, but I got the Lang kit instead.  I do not know if JB tools is an authorized seller of your goods, but the kit was clearly new and not a used item.  I have limited experience with using compression diagnostic tools and was not aware of the limitations of the Sachrader valve.  I knew that they had a low flow rate, but did not know that they could fail in this manner.  Maybe putting a small warning in your text advising people to not do what I've done will help someone avoid my problem.  I have certainly learned some valuable information from this experience and will pass this along to anyone who I feel can benefit.

Hopefully my inspection camera will be here this week so I can look and see if anything is still in the combustion chamber.  I will let you know what I find.

Thanks again for your time regarding this issue (please pass this along to Jim as well).  I am glad that cause of the issue was found.  If Jim is still willing, I would like a couple spare valves.  I am obviously missing 1, but having some spares would be nice.

-Tim
« Last Edit: May 19, 2015, 01:14:47 PM by Twisty »
88 MJ buggy, 4.0/AW4, 203/205, 3 link front/4 link rear on airshocks, 42" Iroks, full hydro

"Only wealthy men can afford to buy cheap things."

Offline Twisty

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Re: Compression test gone very f*****g bad
« Reply #8 on: May 19, 2015, 01:15:29 PM »
Moral of the story is if the valve is subjected to too much flow, it can come apart.  Warning to all!!!
88 MJ buggy, 4.0/AW4, 203/205, 3 link front/4 link rear on airshocks, 42" Iroks, full hydro

"Only wealthy men can afford to buy cheap things."

Offline Bluerocket

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Re: Compression test gone very f*****g bad
« Reply #9 on: May 19, 2015, 01:49:37 PM »
Yikes,   this is a BAD failure for you to recover from for not reading a note in a booklet :(.
Hard to fault anyone for it, but pulling the head is a big job to get the piece out if it didnt hurt the cyl.
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Offline Twisty

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Re: Compression test gone very f*****g bad
« Reply #10 on: May 19, 2015, 03:03:05 PM »
Yes, there is a warning in the manual.  However, like I said in my last email to Bruce, I did not receive an instruction booklet with my test kit. :(


I have been doing my research regarding the course of action I will take if the engine is damaged. 
« Last Edit: May 19, 2015, 03:05:58 PM by Twisty »
88 MJ buggy, 4.0/AW4, 203/205, 3 link front/4 link rear on airshocks, 42" Iroks, full hydro

"Only wealthy men can afford to buy cheap things."

Offline HEYzipupyourfly

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Re: Compression test gone very f*****g bad
« Reply #11 on: May 19, 2015, 03:12:30 PM »
before you try pulling the head( if you confirm there is something in there) i would try blowing compressed air into it to try and get it to evacuate through an open passage.  I've done that before trying to replace the dam ford triton spark plugs and had luck.
just want to probably pull the rockers so you know its not going to head up into the intake or exhaust and turbo. maybe disconnect the turbo, prop open the exhaust valve and try to blow it out that way.
I once read in a bathroom stall, "You can't rush perfection"

Offline jerry k

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Re: Compression test gone very f*****g bad
« Reply #12 on: May 19, 2015, 10:39:09 PM »
Good luck Tim..I hope it works out for you.
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Offline Twisty

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Re: Compression test gone very f*****g bad
« Reply #13 on: May 23, 2015, 08:32:51 PM »
Just an update.  I got the truck back together today, and all appears to be fine. 

The camera was absolutely deplorable.  The image quality was poor, and as it warmed up it got worse!  I could see condensation on the inside of the lens and the image was foggy and wavy.  I could only use it for 2 minutes before needing to let it "cool down."  But that was long enough for me to poke it inside the cylinder and have a look around.  I saw nothing, so I put new o-rings (another $20 ::)) on the injectors and buttoned everything up.  Before I put the glow plugs back in I did one last compression test on the suspect cylinder, and it was 425psi.  Considering it was 365psi before this happened, I'm pretty sure that nothing was damaged by the debris.  I think that the second test was so much higher because my batteries were fully charged.  I think the pieces had passed through the exhaust valve and were in the manifold/up pipe.  They had to go through the turbo, but I'm not as concerned about that as I am the engine.  I took it for a 3-4 mile drive today and it sounds great, especially when at WOT on the 100hp tune.   8)

Now I'm going to change the oil and return this POS camera. 
« Last Edit: May 23, 2015, 08:35:25 PM by Twisty »
88 MJ buggy, 4.0/AW4, 203/205, 3 link front/4 link rear on airshocks, 42" Iroks, full hydro

"Only wealthy men can afford to buy cheap things."

Offline rich

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Re: Compression test gone very f*****g bad
« Reply #14 on: May 24, 2015, 03:58:57 AM »
Awesome
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