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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal><span lang=DE>Hello Marcel,<o:p></o:p></span></p><p class=MsoNormal><span lang=DE><o:p> </o:p></span></p><p class=MsoNormal>Your engine has leaking valves.<o:p></o:p></p><p class=MsoNormal>It won’t get better from changing measurement procedures.<o:p></o:p></p><p class=MsoNormal>Maybe the seat is rough, or the valves bent, or offset .<o:p></o:p></p><p class=MsoNormal>Something to make sure about.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Enlarging the valve leash could result in hammering everything dead in the valve train.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Cheers<o:p></o:p></p><p class=MsoNormal>Chris<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span lang=DE>Von:</span></b><span lang=DE> Fot <fot-bounces@autox.team.net> <b>Im Auftrag von </b>van.mulders.marcel--- via Fot<br><b>Gesendet:</b> Samstag, 2. Mai 2020 14:43<br><b>An:</b> fot <fot@autox.team.net><br><b>Betreff:</b> [Fot] Valve overlap and compression test<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana",sans-serif;color:black'>A leaking test on my TR6 engine is showing a leaking exhaust valve on cyl no 1 (48% on the gauge of the device) and a leaking inlet valve on cyl no 2 (75%). Compression on cyl no1 is 9.5 bar and on cyl 2 it is 8 bar. The compression on the other cylinders is between 12 and 13.5 bar. This is with a race cam with a valve overlap of 110° (320-F grind). Because of the high overlap, the piston has risen a lot before the inlet valve is closed, so I did the compression test again, but with a valve lash of 2.5mm/0.1" : compression went from 9.5 bar to 14.5 on cyl no 1 and from 8 bar to 15 on cyl no 2. With this valve lash, the compression on the other cylinders went up to 16 - 18.5 bar. Of course, when the engine is running at high rpm, a lot of valve overlap is necessary for best cylinder filling, but I wonder if 110° isn't too much?? The recommended valve lash is 0.40mm/0.016" when the rocker ratio is 1.45(0.43mm/ with my 1.55 roller rockers). Would it be risky to set the valve lash at some 0.05mm/0.002" higher?<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana",sans-serif;color:black'>PS : is it common practice to set the valve lash at a couple of mm to perform a compression test, because it seems that the valve lash has a lot of influence on the result when testing a race camshaft?<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana",sans-serif;color:black'>Marcel<o:p></o:p></span></p></div></div></div></body></html>