Bumble
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| posted on 8/8/10 at 04:20 PM |
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Compression Test Result.......
Further to this post LINK I carried out compression test today.
Cyl 1 - 70 psi
Cyl 2 - 120 psi
Cyl 3 - 120 psi
Cyl 4 - 140 psi
Think I've found why I'm only running on 3 cyls....not happy. I have no idea as to history of the engine other than it's from a
'97 Escort.....so should I shell out a few ££££'s and buy another (maybe a 2L pre 95 Silvertop if I can find one) or strip it down in the
car and try and try to fix??
I can't decide.
Matt
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Strontium Dog
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| posted on 8/8/10 at 04:25 PM |
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If the problem is head related you can do it in the car. If it is bore related you can't!. Pour a teaspoon of engine oil down the plug hole and
repeat the test. If the compression rises then it is bore/piston related and if it stays the same then it is head gasket or valve etc.
Mind you, if your tester is accurate 120psi is not very good although high enough to run!
[Edited on 8/8/10 by Strontium Dog]
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FrankP
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| posted on 8/8/10 at 04:27 PM |
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I would whip the head off and have a look - if the cylinders and bore look ok it could be a burned out valve and valve seals etc. If the head is
dodgy you can have it overhauled for a couple of hundred quid and then you know what your dealing with rather than take another punt on a different
engine with an unknown history.
Once you have the head off if it is u/s the you know where you are..
Cheers
Frank
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omega 24 v6
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| posted on 8/8/10 at 05:33 PM |
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You did do it with a wide open throttle didn't you ??
If it looks wrong it probably is wrong.
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NigeEss
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| posted on 8/8/10 at 05:39 PM |
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Ditto the oil trick, narrow the problem down first.
Time is an illusion. Lunchtime doubly so.................Douglas Adams.
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Bumble
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| posted on 8/8/10 at 05:40 PM |
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Er no......didn't realise it made any difference.....
quote:
Originally posted by omega 24 v6
You did do it with a wide open throttle didn't you ??
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rusty nuts
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| posted on 8/8/10 at 05:40 PM |
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A cylinder leakage test is far better than a compression test . Had an Escort with a rough idle about 10 years ago that had been compression tested
several times, cylinder leakage test showed a leaking inlet valve straight away
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omega 24 v6
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| posted on 8/8/10 at 05:49 PM |
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I'd do it again then the results will be much different. Although cyl 1 is way out probably either way.
If it looks wrong it probably is wrong.
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MakeEverything
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| posted on 8/8/10 at 05:52 PM |
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quote:
Originally posted by Bumble
Er no......didn't realise it made any difference.....
quote:
Originally posted by omega 24 v6
You did do it with a wide open throttle didn't you ??
it doesnt.
I would take the head off. Any problem is likely to be fairly obvious from the sgns youll see. It could even be a blown head gasket.
[Edited on 8-8-10 by MakeEverything]
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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britishtrident
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| posted on 8/8/10 at 05:55 PM |
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Very bad set of results just a totally worn out engine.
You did have the throttle held full open and all 4 plugs out when doing the test ?
[Edited on 8/8/10 by britishtrident]
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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MakeEverything
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| posted on 8/8/10 at 06:05 PM |
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quote:
Originally posted by britishtrident
Very bad set of results just a totally worn out engine.
Depends what the compression of the engine is "Normally".
Asking a silly queston, but its not a low compression engine is it?
In all honesty, it could just be a head gasket.
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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big_wasa
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| posted on 8/8/10 at 06:27 PM |
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its a 1.8L zetec thats been stood years. My money is on a stuck ring or sticky tappet. Worth doing the compresion test again with a drop of oil down
the bore.
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britishtrident
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| posted on 8/8/10 at 07:15 PM |
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180 PSI with no more than a couple of pounds variation between cylinders would be a healthy result for a typical 16v 1.8 tin top engine -- even one
with a big mileage.
[Edited on 8/8/10 by britishtrident]
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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MakeEverything
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| posted on 8/8/10 at 07:38 PM |
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I think for an engine with some mileage (lots) those figures i could live with (Except cylinder 1).
Rebuilding would reset these with a decent budget, but i honestly wouldnt really worry too much about the baseline. Its the one cylinder underneath
the baseline that is of concern, but as said, i would be surprised if it was anything more than just a head gasket or sticking valve.
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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Strontium Dog
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| posted on 8/8/10 at 08:00 PM |
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quote:
Originally posted by rusty nuts
A cylinder leakage test is far better than a compression test . Had an Escort with a rough idle about 10 years ago that had been compression tested
several times, cylinder leakage test showed a leaking inlet valve straight away
Leak down testers also allow you to check the state of the bore at different points. Very much better than an ordinary comp tester. You do need a
compressor to use one though!
Easy enough to make too, just check the link below
http://www.max-boost.co.uk/max-boost/internet_articles/Building%20and%20Using%20a%20Cylinder%20Leakdown%20Tester.htm
I'd expect a value of 1% on a new build competition engine and anyt engine with over 10% has a problem although it will run. 6% would be
acceptable for a road going engine in use!
You can hear leaking vaves as the escaping air will hiss!
[Edited on 8/8/10 by Strontium Dog]
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