Borescope Any Good?
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Borescope Any Good?
Hello:
Has anyone ever used a borescope to look thru the spark plug hole to visually see any problems in cylinder?
I have a 4.6 with low compression in only 1 cylinder. When I removed the spark plug it was smashed and all the lower porcelin was gone.
I would like to know if there is a valve problem.
Has anyone ever used a borescope to look thru the spark plug hole to visually see any problems in cylinder?
I have a 4.6 with low compression in only 1 cylinder. When I removed the spark plug it was smashed and all the lower porcelin was gone.
I would like to know if there is a valve problem.
Posting Guru
Joined: Apr 2003
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From: Wyoming
Just use a compression check fitting and hook it up to your air compressor. Put some air into the cylinder and see which way it blows out. Either way, it sounds like you dropped a valve into the cylinder.
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Thanks for the reply. The engine runs good. It does however have a slight "miss".
If I let it idle for awhile it will get worse and the "check engine" light will come on with a miss code for that cylinder. If I take the plug out, it will be wet. If i wipe off then reset light it seem to be good again.
If I let it idle for awhile it will get worse and the "check engine" light will come on with a miss code for that cylinder. If I take the plug out, it will be wet. If i wipe off then reset light it seem to be good again.
Posting Guru
Joined: Apr 2003
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From: Wyoming
Back to your original question, the use of a boroscope. I would be surprised if you could detect problems with ring sealing with a boroscope. YOu might have some luck with seeing obvious problems with the valves if the boroscope has a 90 degree angle (like a periscope).
Lead Driver
Joined: Sep 2006
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If the compression pressure is down, the PCM detects this as longer rotation time for that cylinder.
This sets a code for that cylinder.
The PCM can't tell a reason for lower power from any cylinder be it from a plug, a coil, a bad valve, broken piston, broken rings, scored cylinder wall, broken valve spring, etc.
All it knows is the power is down via a complex set of software functions that actualy measures the contributuion to rotation time useing the crank position sensor to measure.
Ways to check what might be wrong is the use of a vaccum gauge on a running motor but interpetation of the needle action is required. Back this up with a compression test and oil added to the cylinder for a ring seal check etc.
You can get a good idea from these tests if the head has to come off to fix the problem.
This sets a code for that cylinder.
The PCM can't tell a reason for lower power from any cylinder be it from a plug, a coil, a bad valve, broken piston, broken rings, scored cylinder wall, broken valve spring, etc.
All it knows is the power is down via a complex set of software functions that actualy measures the contributuion to rotation time useing the crank position sensor to measure.
Ways to check what might be wrong is the use of a vaccum gauge on a running motor but interpetation of the needle action is required. Back this up with a compression test and oil added to the cylinder for a ring seal check etc.
You can get a good idea from these tests if the head has to come off to fix the problem.
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Joined: Aug 2007
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From: CANADA
Yah, a leak down test is probably best. I use boroscopes in industrial engines alot, and they work great. But we also use them along with compression testers. Any decent scope should be able to swivel in all directions, great for seeing valves, cylinder walls and the top of the piston. No you cant see ring wear exactly, but seeing the cylinder walls can usually help diagnose that as well. I dont know how hard it is to pull a valve cover on a 4.6 but Id look under there as well. Sounds like it might have to come off anyway. Strange? you'd think you would hear more noise. Spark plugs dont smash themselves.
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There is no noise that I can hear. I would expect if there was a broken valve spring etc. you would hear noise.
I was thinking if something has lodged in between the valve & seat or damaged the face(s) that would allow a leak.
I bought this truck with this problem existing and found the smashed plug.
After changing all the plugs & wires, the problem with a miss and the slight vibration has all but vanished but, it is still noticeable. If I keep the RPM's at 800 or more it seems perfect.
THANKS TO ALL FOR YOUR HELP!!
I was thinking if something has lodged in between the valve & seat or damaged the face(s) that would allow a leak.
I bought this truck with this problem existing and found the smashed plug.
After changing all the plugs & wires, the problem with a miss and the slight vibration has all but vanished but, it is still noticeable. If I keep the RPM's at 800 or more it seems perfect.
THANKS TO ALL FOR YOUR HELP!!
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