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water in the oil?
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Bill Layton View Drop Down
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Points: 551 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Bill Layton Quote  Post ReplyReply Direct Link To This Post Posted: 04 June 2012 at 4:34pm
The head and cylinder are cast steel but the block is aluminum. 
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Bill Layton View Drop Down
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To add more to this phenomenon, the lifters sit in the aluminum block. So when it gets warm it expands moving the push rod towards the head. Since the rockers are adjusted at the top end (cylinder head) it can't compensate for this, and the valve lash effectively diminishes. Unless you adjust them when the engine is hot like one normally would on any other engine. Anyone that wants to use the original tolerances needs to consider this. I've seen engines that were 2, 5, 10, 15 and 20 yrs old and suddenly no compression,  do a valve adjustment and bingo all is well again. Most valve lash would get loose over time but this is the opposite oddly enough.
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bal149 View Drop Down
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Points: 67 		Post Options Post Options   Thanks (0) Thanks(0)   Quote bal149 Quote  Post ReplyReply Direct Link To This Post Posted: 04 June 2012 at 8:33pm
re head and cylinder- I was referring to the need to watch valve lash in an aluminum head-the Bukh of course has an iron head. The Cylinder, I thought, was aluminum with an iron sleeve. But I may be wrong. The pushrods sit on a steel cam which has less expansion. I will of course defer to Bill who has much more experience than I do with these engines and as far as valve lash is concerned, I will look very closely at his recommendations. If the block expands more than the  bearing on which it turns, there will be less block bearing play, but the rockers will not be pushed up by the push rods. If the cylinder grows more than the pushrods, lash will indeed be decreased which is likely the situation in this engine. I will bring a magnet to my boat the next time I go and check what is what.
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frfletch View Drop Down
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You won't need a magnet. The cylinder is one piece, all steel. The crank case is aluminum, and the head is cast iron.
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Seawolf View Drop Down
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Well all is good, put the cooling system back together and fired up the motor, used a infrared thermonitor to track temps on the cylinder and all is good, it runs up to about 65-70 c at idle and a little cooler with the revs up. Ran it for about 20 minutes and I am now happy.

 
The only things left to do is re torque the head bolts after 10 hours of run time.
 
Thanks again!
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Bill Layton View Drop Down
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Hope you greased where the head nuts go onto the threaded rod..... if not, with a cool engine remove one at a time, grease and re torque. When torquing head nuts they should never gall, that is a creaking noise where it feels like the nut is beginning to jam on the threads. If this happens the head doesn't acheive the proper clamping pressure to seal the headgasket. And this is a common problem. Also to compensate for well worn stud threads and rust within the nut I over torque by 10%. This ensures adequate clamping pressure. If you do all this and still find the nut creaks while torquing then the studs would need to be passed thru a die and the nuts retapped or possibly even changing of parts. I've seen some pretty bad studs out there before. 

Edited by Bill Layton - 05 June 2012 at 1:22pm
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Seawolf View Drop Down
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Points: 118 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Seawolf Quote  Post ReplyReply Direct Link To This Post Posted: 06 June 2012 at 3:29pm
I used anti-seized on bolt ends of the bolt. Had no galling, or creaking. Per Keith's reccomendations, I torqued to 7 kps and will torque it to 9-10 kps after 10 hours of run time. Which for me probadly will be at the end of summer. Lots of work to run this little engine for 10 hours. I hate to do the math what it cost me per hour of run time!
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Don't ever do that sort of math!  Too depressing!

I've been following this thread with interest.  Great job Seawolf at all your hard work!
Chris
Eclipse #240
Thunder Bay, ON
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Seawolf View Drop Down
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An update:

 

So far The engine has given me no trouble and continues to operate in 148 – 165 F degrees range. Not trusting my sensors, I have religiously checked the oil and use a laser thermo gun to check the temp on the cylinder and cylinder head. Now I know I have to re-torque the cylinder heads after 10 hours of operation, and I have been keeping notes of operating time, and I have also been checking the fuel level to gauge how much the engine has ran.

 

I thought I read somewhere that the engine burns about 1/3 gallon per hour. Which means after 10 hours I would have burned 3.3 gallons or 1/3 of my tank capacity. Can someone validate that the engine burns about 1/3 gallon per hour? Thanks.

 

 

Mark Gilmore

Commodore, SFSA

Flathead Lake, MT

S/v Seawolf
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fatjohnz View Drop Down
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Points: 304 		Post Options Post Options   Thanks (0) Thanks(0)   Quote fatjohnz Quote  Post ReplyReply Direct Link To This Post Posted: 07 December 2019 at 10:09am
Hi, I'm getting ready to reinstall a reconditioned head. Would you confirm the torque spec and convert it to foot-pounds? I saw Bill's comment to add 10% so I think the value in the manual is understated.
Thanks, john
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John,

I used the torque wrench the first time I put the head back on, I've done it at least three times, and subsequent tightenings I have just tightened it up a notch by feel, so I don't have an opinion on this, nor much experience. I should really do it again now, and your message reminds me that I should take the torque wrench down and do it right. I would go with Bill's recommendation. I will get out my workshop manual for reference and give you the conversion later today.

Frank
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Bill Layton View Drop Down
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A few things that should be done. Pass a die (as in tap and die) over the threads on the studs. Also you must re tap the nuts. This gets the garbage off the threads. Then coat all the threads and studs and nuts with anti-seize compound (gray stuff found at automotive stores) (lots on the threaded parts) This acts as a thread lube and it's far better than using oil. I torque to 60 Foot Lbs the conversion in the manual states 68.6NM and that translates to 50.6 Lbs but I find that too light and I had some gasket failures at this torque. After using 60 Ft Lbs I didn't have anymore problems. Remember once your engine is fully warmed up in the boat to re-torque to 60 FT Lbs again. To do this the nipple on the side of the fuel injector needs to be removed to get access to the top port nut. Then it should last a very long time.

While your head is off be sure the bypass pipe / bracket held on with two 10mm bolts is removed and  inspected as this is where it can get clogged up with rust and sediment and cause a blockage. (bottom stb side of head) This is the usual cause for the head warping to begin with as it allows the head to overheat. 
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fatjohnz View Drop Down
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Points: 304 		Post Options Post Options   Thanks (0) Thanks(0)   Quote fatjohnz Quote  Post ReplyReply Direct Link To This Post Posted: 31 December 2019 at 1:37pm
How do you set the pushrods? thx
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Bill Layton View Drop Down
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The service manual states:

"When fitting the pushrods it should be observed that the pushrod which is nearest to the cylinder is for the inlet and the one furthest away is for the exhaust. When being inattentive it may be possible to exchange the pushrods by mistake."

This is all that is stated in the workshop manual. I can email this to you if you'd like a copy.

In short the pushrods and lifters are positioned vertically. The top pushrod is the intake and the bottom rod is exhaust. The trick is to put them in place with the ball pushed into the lifters using grease to hold it there in place. Then try to slide the head in place without moving anything. It's awkward and take's few tries.

Aside of this valve lash should be the same numbers but in thousands of an inch ( 20 +25 thou) They spec this in mm but the factory spec is too tight and caused problems down the road. 
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fatjohnz View Drop Down
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yes, I was stuck at the awkward part. Bearing grease on the rod tips did the trick. Thanks Bill.
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fatjohnz View Drop Down
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Points: 304 		Post Options Post Options   Thanks (0) Thanks(0)   Quote fatjohnz Quote  Post ReplyReply Direct Link To This Post Posted: 01 January 2020 at 1:45pm
I can get 18 thou lash on the intake but not 20. I hope that's ok. js


Edited by fatjohnz - 01 January 2020 at 4:40pm
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Bill Layton View Drop Down
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Close enough and much better than .20mm
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