valve clearance question

I have just replaced the head gasket on my AD3-152. While I had it down I readjusted the valves .012 cold but I think I may have got them a little snug. What would the symptoms be if the valve clearance was not enough? The engine starts great, my only concern is what sounds like a slight sucking sound coming from the exhaust. Would it be wise to readjust with a little more clearance?
 
Your intake valve lift would be a little bigger and your power would come up bit due to more airflow. Your exhaust valves have less seat contact time and run hotter.
 
I'm not an expert on that engine but 12 seems a little tight to me. I would re-torque the head gasket and re-adjust the tappet clearance according to the book. Sometimes the exhausts require more clearance that the intakes. Get it hot, re-torque the head and re adjust the tappets while hot.
 
Hi Robert, bit late coming in on this one but it is essential that the engine is at number 1 TDC for both phases of tappet adjustment. This is confirmed by the TDC line being visible in the engine backplate inspection hole.
DavidP, South Wales
 
I've always felt it was better to have them a little loose than too tight. Never seen a burnt valve from them being too loose. I'm not talking a lot but if your feeler gauge is slightly loose at .012 and tight at .014 I would feel good about that.
 

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