mark newman Posted June 25, 2014 Share Posted June 25, 2014 Hi i need help with valve clearance , what would be the clearance for the inlet, and what would it be for the out let. would you set them the same . thanks mark Quote Link to comment Share on other sites More sharing options...
Ian C Posted June 25, 2014 Share Posted June 25, 2014 If you mean the cam-to-bucket clearances, it's 0.025 intake, 0.035 exhaust. Can't recall if that's imperial or metric Quote Link to comment Share on other sites More sharing options...
mark newman Posted June 25, 2014 Author Share Posted June 25, 2014 yes cam to bucket , so if I got 0.015 intake and 0.015 exhaust , and 1 on the intake at 0.005 . and 2 at 0.010 . exhaust goes from 0.015 to 0.020 Have I got a problem Quote Link to comment Share on other sites More sharing options...
Ian C Posted June 25, 2014 Share Posted June 25, 2014 All those are really tight, when they warm up the gaps will close up (hence exhaust being a bigger gap when cold). Your valves might not seal correctly which can cause poor power, economy, idle etc. and even hotspot under boost causing det. It'll probably be wearing the shims and the camshafts too. Quote Link to comment Share on other sites More sharing options...
Guest FullAttack Posted June 26, 2014 Share Posted June 26, 2014 (edited) I know with the 1j's the tolerance is as follows.. Inlet- 0.006" - 0.010" Exhaust- 0.010" - 0.014" (EDIT- quick bit of google says 2j are the same tolerance.. http://www.mkivsupra.net/vbb/archive/index.php/t-254960.html? ) However, BC cams specify 0.008" on inlet & exhaust... They tighten the gap up to stop the cam lobe flicking the shim off the bucket at mega high rpm.. I usually try to get them all somewhere in the middle, ie 0.008" inlet, and 0.012 on exhaust.. But then I have about 70 spare shims to pick and choose from. Another thing to note, always have the head bolted on the block and torqued down before shimming the head.. A lot of people say it doesn't make a difference, but iv checked a head that had been shimmed by machine shop before assembly, after torquing the head down and rechecking I had to change 8 shims.. Edited June 26, 2014 by FullAttack (see edit history) Quote Link to comment Share on other sites More sharing options...
Guest FullAttack Posted June 26, 2014 Share Posted June 26, 2014 yes cam to bucket , so if I got 0.015 intake and 0.015 exhaust , and 1 on the intake at 0.005 . and 2 at 0.010 . exhaust goes from 0.015 to 0.020 Have I got a problem I'd say yes, you have a problem... But all problems have a solution;) The gap is too big, it has been known for shims to be flicked off the bucket at high rpm.. Shims may not be the cause.. The large gap is often the affect... The cause is possibly down to your valves & valve seats being coked up, thus not seating properly, which is stopping the valve from returning all the way back up. If this is the case, the solution is to remove the head and lap the valves.. Change Valve Stem Oil Seals, Skim head and Head gasket.. Quote Link to comment Share on other sites More sharing options...
mark newman Posted June 29, 2014 Author Share Posted June 29, 2014 Yes thanks for that ,did your valve clearance get bigger or smaller when you bolted the head down. Quote Link to comment Share on other sites More sharing options...
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