k20z1ej1

A little background: I have a b18b, it had a misfire. I replaced everything ignition and fuel related, no change. Decided it was probably mechanical, pulled the head and took it to my machine shop. They found a bent valve. They replaced it with a new oem valve, cut new seats and lapped the valves. I put the head back on, adjusted valve lash before cranking it (cold.) I set intake at .005 (spec is .003-5) and i set exhaust to .008 (spec is .006-8.) i fired it up and it sounded like ****, head making intermitent noise and its misfiring much worse than before. The machine shop listened to it and they think its either A) worn out cams, or B) a bad rocker. I checked lash hot and its significantly looser than before. I measured .013 on the exhaust. My boss says that lash tightens as the engine warms. That makes sense right? Metal expands when heated etc. I did some googling and the number of people that say "looser when hotter" is about the same as the number of people that say "tighter when hotter" !!!!!!!!!!!! what the **** is going on?!?!? Does lash get looser or tighter as the engine warms?

I do not care for "theory" or "opinions."

If you are and engine builder or shop owner or someone who KNOWS, please chime in and tell me what you know. Thanks in advance!

pogeeboy27

iTrader: (3)

Just check your clearances when the engine is cold. If there is a change in your clearances from when you set them then you may not have tightened the lock nuts or the adjustment screw turned a bit as you tightened the lock nut. As long as you set the clearances correctly there should be no weird noises.