HELLO MY BOAT IS A HUNTER 29.5 WITH A YANMAR 2GM20F engine
could you pleae inform the intake7Exhaust valve clearance ?
Regards
could you pleae inform the intake7Exhaust valve clearance ?
Regards
Clearance Of Intake/exhaust Valves
- Thread starter santiago47
- Start date
http://hunter.sailboatowners.com/in...ds&Itemid=287&brand=2&id=0&model=gen&page=gen
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Clearance for both intake and exhaust is 0.2mm or about .008", cold. If ya have no history on the engine, it might be prudent to torque the head bolts (29-32 ft-lb) while you are in there. The manual in the downloads section that Ralph referenced has the tightening sequence.
From memory the clearances mentioned are correct.
I do not understand why you would re-torque head bolts. However - as I recall - there are 8 head bolts. Two are 8mm bolts the other six are 12mm. The torque values are different for each size. Anyway check the manual for what Yanmar says about re-torque. Also check the manual for torque values. 32 ft-lb is way too low for 12mm head bolts but it might be right for rocker arm supports.
Charles
I do not understand why you would re-torque head bolts. However - as I recall - there are 8 head bolts. Two are 8mm bolts the other six are 12mm. The torque values are different for each size. Anyway check the manual for what Yanmar says about re-torque. Also check the manual for torque values. 32 ft-lb is way too low for 12mm head bolts but it might be right for rocker arm supports.
Charles
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If the engine uses torque to yield head bolts then I'd not tighten them. You generally replace head bolts if pulling a head for any work.
My mistake on the torque number.. the correct torque is 72 ft-lb for the big nuts and 18 for the two small ones on the exhaust side. The other number is the torque for installing the head stud into the block.. Yanmar does recommend re-torquing the head after 50 hours and then every 1000 hours after that.