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Discussion Starter #1 (Edited)
I'm rebuilding the water jacket and head of a 1987 3 cylinder 1200cc 2 stroke Yamaha outboard. It had a small water jacket leak... I can't handle leaks. Number 31 in the attached picture.

Should I use new bolts or is it OK to re-use the old ones? We're not talking very much torque here and they are grade 8. I've chased out all the female threads with a new tap and Kroil to get all the old grunge out of the holes, and plan on using compressed air to clean them prior to final assembly.

The head is aluminum and the VERY expensive OEM bolts appear to be some sort of chrome alloy - VERY shiny - and nothing like I can source locally, even though they are grade 8.

Also, should I use a high temp Nickle anti-seize, or is a drop of motor oil - with less final torque acceptable? The threads on the bolts were bone dry from the factory.

The reason I ask about the anti-seize is that I got to go through the wonderful experience of extracting two VERY corroded bolts that snapped off flush in the head. I managed to save the threads but it took 3 HOURS to get the little boogers out. :mad:

Good times! :D
 

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Lets see if I got this right.

You had a leak, gasket #31 in the parts drawing. Sealing surfaces OK? No nicks, dings?

Usually head bolts get a drop of oil, but......... In this case with what appears some sort of an alloy or plating, probably something to do with corrosion resistance, I'd contact the factory.

Usually a good idea to chase threads but be sure you used the right tap. Cut threads or rolled threads on the bolts? Not sure if this is the case with an engine of this size but something to look at.

Lacking any guidance from the factory, I would use an anti seize. Would also add a drop of oil to get the correct torque.

The corrosion in the bolts you mentioned. Caused by the leak?
 

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You might want to go talk to some mechanics that work on those motors every day . The way I understand it , If you put anti seize on those bolts , it will change the amount of torque that is put on them when you tighten them down . You will be over tightening them ,& you might just strip out the threads .
 

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Discussion Starter #4
Thanks guys - I did get a hold of a factory tech. The bolts are thickly chrome plated for corrosion resistance and I decided to order new ones.

The old bolts had the surface corroded and that was enough to cause them to snap, the leak was at the gasket right next to the bolts, it appears as though the corrosion from the bolt also etched into the gasket. 25 years of exposure to our very hard water (scale) was enough to start the irreversible process.

A drop of oil is the recommended lubricant with a 3 stage torque down. That's going to take some time since there are 18 plus 14 bolts total - that means 96 steps! :eek:
 

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Come and help me put a set of heads on a V 20 one day. Initial torque to 100, second to 150, final to 200, then an additional 70 degrees. 80 head bolts on this engine.

Glad you got the right info.
 

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RonKMiller said:
I'm rebuilding the water jacket and head of a 1987 3 cylinder 1200cc 2 stroke Yamaha outboard. It had a small water jacket leak... I can't handle leaks. Number 31 in the attached picture.

Should I use new bolts or is it OK to re-use the old ones? We're not talking very much torque here and they are grade 8. I've chased out all the female threads with a new tap and Kroil to get all the old grunge out of the holes, and plan on using compressed air to clean them prior to final assembly.

The head is aluminum and the VERY expensive OEM bolts appear to be some sort of chrome alloy - VERY shiny - and nothing like I can source locally, even though they are grade 8.

Also, should I use a high temp Nickle anti-seize, or is a drop of motor oil - with less final torque acceptable? The threads on the bolts were bone dry from the factory.

The reason I ask about the anti-seize is that I got to go through the wonderful experience of extracting two VERY corroded bolts that snapped off flush in the head. I managed to save the threads but it took 3 HOURS to get the little boogers out. :mad:

Good times! :D
Ron, is this for that kewl new houseboat ghetto mod we saw last week? For that kind of rig, I'm surprised that you didn't upgrade to the 1992 Sears "Ted Williams" outboard! :D
 

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Discussion Starter #7
hallzee said:
Ron, is this for that kewl new houseboat ghetto mod we saw last week? For that kind of rig, I'm surprised that you didn't upgrade to the 1992 Sears "Ted Williams" outboard! :D
Too funny, maybe if they had a Pete Rose signature model I would have gone for it! (TMI - we both dated the same girl back in the late 70's) :eek:

Interesting thing is that Yamaha made the EXACT same engine up until 2006 when CARB finally doomed it - but you can still find new ones for sale. They started the line in 1984, so I guess a 22 year run ain't too bad!

Once I did the initial compression check I was in luv. I like keepin' the old stuff hummin'. ;)

...and at almost $8K for a new one... :crazy:
 

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Discussion Starter #8
gunny said:
Come and help me put a set of heads on a V 20 one day. Initial torque to 100, second to 150, final to 200, then an additional 70 degrees. 80 head bolts on this engine.

Glad you got the right info.
80 head bolts? :wow: That's more like a one week job!
 
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