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Do you routinely replace bolts when installing a head?

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PhilSch

Regular Contributor
I know the standard, best practice answer is replace them but at $230 for twenty new bolts that's a big cost to add to the rebuild budget. I have installed heads on many types of motors using old head bolts without problems and in fact did it a few months ago on a 1986 60 horse Evinrude, again with good results. Do the professionals always go with new ones when it comes to outboard engine rebuilds?
 
PhilSch said:
I know the standard, best practice answer is replace them but at $230 for twenty new bolts that's a big cost to add to the rebuild budget. I have installed heads on many types of motors using old head bolts without problems and in fact did it a few months ago on a 1986 60 horse Evinrude, again with good results. Do the professionals always go with new ones when it comes to outboard engine rebuilds?
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Almost never. Unless badly rusted. But then you probably couldn't get them out anyway.
 
Something about--- " torque to yield "----on car engines.----Even so on a V-4 Johnson outboard you would go to the local nut / bolt supply store and buy some bolts for 39 cents a piece.----There is nothing special about these bolts.------Some folks do not understand the concept of spare parts " pricing "-----If they take the order / find the bolt / package the bolt / invoice the dealer and charge you 39 cents somebody is LOOSING money !!!
 
Auto engines are specifically engineered to be more difficult and expensive to rebuild. Why? So most folks can't do their own repairs anymore. Regardless of that most outboards engineered prior to 2010 are fairly straightforward and bolts can be reused as long as they're in good condition as aformentioned. Honestly I haven't done a major overhaul on anything newer than 2003. There is plenty of work out there for those that want to focus on the earlier machinery. As most techs here are retired or semi retired they probably share my thoughts and that is that the complexity of the new equipment can get overwhelming.
Welcome back Mr. Scott, good to hear from you again.
 
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Fastenal..... I nearly always install new as I don't know if somebody prestressed with air impact. If I can tell the motor is virgin and never dinked with I will reuse em.
 
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Amen, Pappy. I like working on virgin stuff if possible. On the big ships say 8000 hp. We measure critical bolts for stretch, for instance connecting rods. We actually torque them in some cases while measuring stretch. There are 4 cap bolts in each rod. Torque in specific sequence, and in stages, of course. New bolts are $350 bucks each. So a V18 has over $25,000 worth of rod bolts. My boss charges 1.5 million for a standard overhaul which happens every 4 years. Some engines have been overhauled 12 times already. Most ships have 2 engines, some even 3. There is absolutely NO ROOM to overhaul 2 engines at the same time.
 
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Yup....Have to do monthly bolt torque checks on my Gensets..Cummins 750K and 1000K units..

genset.jpg
 
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