Carl2704 Posted May 22, 2011 Share Posted May 22, 2011 And the fun continues!!Having had a few issues with the running of my engine, rebuilt and having covered approx 700 miles ish.... I ran a compression test. I took the car out for a 20 mile drive, got home had a cup of tea, took out the plugs wearing insulated gloves, ran the compression tester on all cylinders turning over and foot to the floor... The readings were between 55 PSi and 70PSi across all six cylinders!In the Haynes it says that the PSi figure is less important than the balance of +/- 5PSi across the range.So is my PSi figure low? Should I be worried?Many thanks,Carl Link to comment Share on other sites More sharing options...
JohnD Posted May 22, 2011 Share Posted May 22, 2011 Next step is to add teaspoon of oil to each cylinder just before repeating the compression test. A rise in pressure indicates poorly sealing rings, no rise poorly sealing valves.As Haynes says, the absolute pressure doesn't matter - compression testers are not precision instruments, and are uncalibrated, so impossible to compare between different gauges.John Link to comment Share on other sites More sharing options...
Nick Jones Posted May 22, 2011 Share Posted May 22, 2011 Carl,PSI figures are low - but fairly even. How many compression strokes did you allow each cylinder? I normally allow at least 5. Were all the plugs out when you did this?What running issues? What history on the engine? One possibility is that you have a deep chamber head from a 2.5 or dome-piston 2.0 fitted on a 2.0 with flat-top pistons - which will give a low compression ratio and low cranking pressures.CheersNick Link to comment Share on other sites More sharing options...
tim_trinda Posted May 23, 2011 Share Posted May 23, 2011 3538 wrote:And the fun continues!!So is my PSi figure low? Should I be worried?CarlSome info on compression tests for you http://www.pumaracing.co.uk/comp.htm Link to comment Share on other sites More sharing options...
Carl2704 Posted May 23, 2011 Author Share Posted May 23, 2011 Interesting I don't like the sound of the puma racing synopsis!! The engine block is an ML so Triumph 2000, would this have any baring? Link to comment Share on other sites More sharing options...
tim_trinda Posted May 23, 2011 Share Posted May 23, 2011 3538 wrote:The engine block is an ML so Triumph 2000, would this have any baring?ML should be OK - I used an MM block (2.5 something) to build a 2L for thew GT6.My GT6 had the flat top piston/late head combination mentioned by Nick i.e. sub 7:1CR - no performance but it had a very smooth tick-over :K) Have you tried the comprssion tester on another engine - if you get similar results it may be time to invest in another gauge. Link to comment Share on other sites More sharing options...
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