headbolts on a 120 mercruiser

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rpatton

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My fatherinlaw had a impeller go bad, i mean that the brass sleave came loose from the rubber which made the impeller stop spining at high RPM. Damage is cylinder 1+4 are at 130psi and 2+3 are at 80psi when i tested it . So i figured a blown head gasket and when i took the head off i can see where it was leaking between 2+3 and just started leaking into #4. everythig else seems fine so im going to put it back together and hope but the question i have is can i reuse the headbolts or are they ounce and done. Thanks and sorry for the long story.
 
RogersJetboat454

RogersJetboat454

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Re: headbolts on a 120 mercruiser

Should be able to re-use the head bolts as long as they're in serviceable condition.

Did you check the head and block for warpage?
 
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rpatton

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Re: headbolts on a 120 mercruiser

Not yet but plan on checking them. The bolts are fine just need to wire wheel them to clean the threads then run a tap in the deck holes. My book is telling me to torque the head to 93 ft lbs does this sound right . It sounds light to me
 
RogersJetboat454

RogersJetboat454

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Re: headbolts on a 120 mercruiser

rpatton said:
Not yet but plan on checking them. The bolts are fine just need to wire wheel them to clean the threads then run a tap in the deck holes. My book is telling me to torque the head to 93 ft lbs does this sound right . It sounds light to me
Click to expand...

93 ft lbs sounds about right, but if that information is out of a Clymer, or Seloc repair manual, I'd be wary.
Don't know the vintage of your rig, but with a little searching you may be able to score your self a factory manual for free here;
Boatinfo - The library, containing manuals, brochures and other technical documents from the last hundred years!
 
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rpatton

Petty Officer 1st Class
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Feb 17, 2011
Messages
249
Re: headbolts on a 120 mercruiser

Update i guess im going to machine the head its way out of spec. Another question i thought of is when its back together is there a breakin period i should do until the gasket seats in
 
RogersJetboat454

RogersJetboat454

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Re: headbolts on a 120 mercruiser

Nope.

Generally recommended to run the engine up to temp, then let it cool off and re-torque the head bolts.
 
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