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Belarus valve cover nut removal

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bushhog
Join Date: Oct 2008
Posts: 8 ky
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2008-10-29          157552


Hi guys,The flywheel on my 250a only turns halfway so I am going to take the valve cover off to see if the problem is in the valve. I am not much of a mechanic and am being advised by someone else. My question is do the nuts have a particular sequence and specific torque when reassembling?And how many gaskets will I need to replace? Thanks Bushhog



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Belarus valve cover nut removal

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auerbach
Join Date: Sep 2007
Posts: 2168 West of Toronto
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2008-10-29          157554


Don't know what a 250 is, so this is general.

With the head, you torque the bolts gradually, in a specific sequence, and to the exact final amount. With a valve cover (or oil-pan), you just put it on. If it leaks, give the bolts in that area another grunt. I've not heard of one breaking through uneven tightening, but going from one to another in several steps (like wheel-rim bolts) is recommended.

There is a formula for bolt-width vs final torque, but you can do it by hand-feel to compress the gasket just enough to prevent leaks in a non-pressurized system.

If you get the cover off with the one gasket under it intact (often the case) you can re-use it. If it shreds and it's hard to get a replacement, you can get a tube of gasket guck. ....


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Belarus valve cover nut removal

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candoarms
Join Date: Mar 2007
Posts: 1932 North Dakota
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2008-10-29          157555


bushhog,

Valve cover gaskets should be tightened from the center out to the edge of the cover. Start with the bolts nearest the center of the engine and work your way out to the ends of the heads. You don't need to apply much torque on the valve cover bolts.

There is a recommended valve cover tightening pattern. However, the pattern is generally the same on all engines. The idea is to allow the gasket to squeeze out evenly along the entire surface of the head.

If you start from one end, you'll have too much gasket showing on the other end. If you start from both ends, you could end up with a bubble in the gasket near the center.

Start from the center of the head and work your way outward, alternating between opposite bolts as you go. In other words, if you're standing on the left side of the engine, start with the center bolt closest to you, then tighten the bolt in the center of the valve cover on the right side. Alternate between opposite bolts as you work your way out to the ends of the cover. Do not over-tighten the bolts. It doesn't take a lot of torque to create a seal. 17-20 lb. ft. of torque should be plenty.

You should recheck the valve cover bolts after the first 50 hours of use, as the gasket will squeeze out slightly with the changes in temperature. I do not recommend re-using the origninal gasket.

With the flywheel turning only a half-revolution, I'm not sure that the problem will be found in the valve cover. It sounds to me as though you may have a broken valve, which has become lodged between the piston and the head. Until you get this figured out, DO NOT attempt to start the engine. You could break a rod or piston, crack your head, or even snap your crankshaft.

Joel ....


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Belarus valve cover nut removal

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belarus250
Join Date: May 2008
Posts: 30 NE
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2008-11-19          158026


Bushhog:

If you are careful you will not need gaskets. One nut, as you know, holds the individual valve covers to its respective head. That nut has a copper washer under it that is reusable. The gasket that seals the cover to the head should be reusable, use a little silicone gasket maker to be sure.

As to your problem. Are you sure this is where you should look? Can you explain just what the engine is doing or not doing? Does it only turn half way with the starter, or, can you not turn it over by hand fully? Use the nut on the front of the engine in the centre of the crankshaft pully and a wrench. Let us know. ....


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Belarus valve cover nut removal

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vladimirec
Join Date: Mar 2009
Posts: 29 Croatia
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2009-03-08          160877


As i see most of you mechanics didnt even see 250's engine.
It's quiet possible one of simplest diesel engines.About valve cover - it has two bolts with copper ring(gasket) under each bolt.If cover is removed carefuly,cover gasket will be reusable.The head has 4 bolts and no gasket.Only thing you can see by removing valve cover is if valves are stucked in open position.Best way to rotate the engine is by using a rod on the bolt in front of engine.the one that holds main pulley.It has even markings to determine motor position. ....


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