Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: calibrated on 08 December 2015, 14:18:57
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Just made compression test yesterday on cold engine and got following
Cyl.
2 10.8 bar
4 10.4 bar
6 10.5 bar
5 10.5 bar
3 10.4 bar
1 10.5 bar
For relevance 10.5 bar is 153 psi..is it good or bad....engine has 90 000 miles...
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Its very good, good compression and all pretty similar, its in fine fettle
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Its nice to know that ...so there is no need for warm engine test? As i see on internet different readings up to
225 psi or whatsoever
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Those results look fine to me :y
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When we checked mine on the old Elite, they were round about 165 - 175 psi over the 6 cylinders. No issues with yours - you have only about 6psi range there which is pretty good. :y
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Thank you guys
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Just made compression test yesterday on cold engine and got following
Cyl.
2 10.8 bar
4 10.4 bar
6 10.5 bar
5 10.5 bar
3 10.4 bar
1 10.5 bar
For relevance 10.5 bar is 153 psi..is it good or bad....engine has 90 000 miles...
don't let young bear see this, he'll start on about compression aswell as 0-60. ;D
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here are the fully warmed up figures for that engine
Standard 12 to 15 bar (174 to 218 psi)
Maximum difference between any two cylinders 1 bar (15 psi)
i'm guessing cold figures would be about 1 bar maybe even 2 bar lower perhaps someone here does know.
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My figures quoted above on a cold engine ;)
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From memory, at 170k my 3.2 was 137-142 psi on all but one, which was 129... that was cold and following ingestion of a spark plug tip... not checked recently but happy with the performance over 100k later :y
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I checked the compression on mine when I was doing the head gaskets, got 16bar on all 6 cylinders when cold. Guessing the heads have been skimmed twice now :D
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Jesus! 16bar! :)
Anyone got the factory original compression figures?
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2.0 8v 10.1
2.0 16v 10.8
2.5/3.0 10.8
2.6/3.2 9.8?
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Absolute compression figures depend on the compression tester, speed of the starter motor, temperature, value timing and so on as much as the engine condition and compression ratio, so they can be pretty much ignored.
The important thing is the spread between the readings. No two cylinders will degrade the same way, so, if the engine is in poor condition, you can expect a wider spread between readings. In this respect, I can see nothing wrong with the OP's readings.
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Figures above were Haynes supplied, except for the last one... they suggest 12-15 bar as acceptable test results with the caveat that all cylinders be within 1 bar; presumably the 2-5 bar discrepancy is to allow for variations in testing equipment and how the test is carried out...
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I checked the compression on mine when I was doing the head gaskets, got 16bar on all 6 cylinders when cold. Guessing the heads have been skimmed twice now :D
Were you cranking it with the throttle shut, as that tends to raise the numbers?
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I checked the compression on mine when I was doing the head gaskets, got 16bar on all 6 cylinders when cold. Guessing the heads have been skimmed twice now :D
Were you cranking it with the throttle shut, as that tends to raise the numbers?
I was still rebuilding it so the plenum wasn't even on ;) Battery was fully charged right enough.
I had the heads skimmed - one was corroded where it was leaking between the cylinder and the water jacket, and also, the exhaust valves & seats were re-cut (inlets were immaculate). The heads have been off before when they went away to Mr Blydenstein and I suspect they were skimmed then too. The coolant bridge was a little reluctant to go back on, seemed like the heads were a little closer together than they ought to be :)
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Done a hot engine compression test as following
1. 203 psi
2. 203 psi
3. 206 psi
4. 206 psi
5. 200 psi
6. 200 psi
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Good consistent results there mate