Westerbeke Cylinder Head Torque Procedure

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Birdman737

Birdman737

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Apr 15, 2012
36
Catalina 400 Milwaukee, WI
Greetings all!

My 17 year old Westerbeke 42B FOUR has just shy of 900 hours on it, and through some research I'm guessing the engine has never had it's cylinder head bolts retorqued before. According to the manual, this should be done every 500 hours just prior to checking the valve clearance... so it's, um, a little overdue (I've only owned the boat a year). The engine runs great.

Yesterday I took the rocker cover off to see how I would get at about 2/3 of the bolts hiding under the cover. I quickly noticed this wasn't going to be easy... many of the cylinder head bolts are under the camshaft (ugh). Also, it appears that the camshaft supports are also held in place by some of the cylinder head bolts.

Any suggestions on a proper course of action? I'm not sure I can tighten them in sequence with the camshaft in place, nor loosen all of them in reverse or forward sequence with the camshaft in place. Nor am I sure I want to loosen ALL of them before retorquing...

I remember this being about a 10 minute job on my Yanmar on the last boat. Hmm.

I'm guessing I shouldn't blow this off and put another 150 hours on it before this winter and do it then, right?

Thanks ahead of time for your suggestions!
 
Bill Roosa

Bill Roosa

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Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
I would suspect that the cam shaft bolts do not go into the cylinder block.
the pattern is the standard "cross pattern" working from one end to the other the starting on the end where you started with the other side's bolt
If the camshaft bolts held down the head the manufacturer would not be able to install the head then send it down the line to install the camshaft.
 
Birdman737

Birdman737

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Apr 15, 2012
36
Catalina 400 Milwaukee, WI
Yeah, you're right... thanks. I was looking on the wrong side of the camshaft. I guess it's not as impossible of a task as I first thought.

However, does anyone have any advice or know of anything I need to worry about or be careful about when removing the camshaft? Do I need to worry about something going, "ping!" and having to spend a day looking for something that flew around the boat? Obviously I'll be adjusting the valve clearances afterward!
 
Birdman737

Birdman737

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Apr 15, 2012
36
Catalina 400 Milwaukee, WI
Ugh, and sorry, my terms are incorrect. It's not a camshaft... this isn't an overhead cam engine... it's the shaft that the rocker arms mount to (don't know the name).
 
Chris Patterson

Chris Patterson

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Oct 17, 2011
2,809
Ericson 29 Southport..
As I remember, and I've done this recently, the rocker arm support is not part of the head bolts. Just take the bolts out, (with the engine rotated T.D.C.), and the rockers come smooth off. And the head bolts should be loosened incrementally, in the reverse order that you would torque them.
 
Birdman737

Birdman737

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Apr 15, 2012
36
Catalina 400 Milwaukee, WI
Done! Thanks!

It was much easier than I originally thought. Four bolts removed the entire rocker assembly, giving me access to the cylinder head bolts. My back wasn't very happy with me the next day after backing out the cylinder head bolts before retorquing them, so maybe next time I'll get a longer wrench or extend the wrench handle with a pipe.

Checking the valve clearance went fine, too.

I should be good for a few more years.
 
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