Question

[billy pitcock]

I have a Huskee lt4200 mower with a 420cc morepower engine. I need the valve specs (if there are any) to reset the valves on this engine. I cannot find the specs anywhere. Can anyone help.

Thank you

 

[The Specialist]

I have a Huskee lt4200 mower with a 420cc morepower engine. I need the valve specs (if there are any) to reset the valves on this engine. I cannot find the specs anywhere. Can anyone help.

Thank you

If you have an overhead valve engine, the clearance is .006 thousands of an inch for both valves. The piston must be at top dead center between the compression and power stroke.

If it is a Briggs L shape system, then the intake is .006 and the exhaust is .009. Again at DTC of the compression stroke and the power stroke.

 

[cpurvis]

Wouldn't it be better to set the valve clearance with the cam follower directly opposite the peak lift portion of the cam lobe?

 

[Rivets]

Not all OHV engines have a valve clearance of .006” and not all Briggs L-head engines have the same clearance. Please give us the brand of engine you have with all model, serial and spec numbers from the engine. Where to set valve clearances will also depend on the type of compression release is used on your particular engine.

 

[The Specialist]

Wouldn't it be better to set the valve clearance with the cam follower directly opposite the peak lift portion of the cam lobe?

And exactly where is that?? Just before top dead center on the compression stroke. so if you set the valves there, as soon as it passes you have a bigger valve gap, which then you will get the clacking of the rocker arms. I always have done it at TDC or just past, so the valves are at complete rest on the seats. This prevents the clacking of the rocker arms.

 

[cpurvis]

And exactly where is that?? Just before top dead center on the compression stroke. so if you set the valves there, as soon as it passes you have a bigger valve gap, which then you will get the clacking of the rocker arms. I always have done it at TDC or just past, so the valves are at complete rest on the seats. This prevents the clacking of the rocker arms.

Here is 'exactly where that is:'

You don't set both valves at one crankshaft position.

Rotate the crank until the exhaust valve begins to open. At that point, the intake cam follower is directly opposite of max lift on the lobe. Set the intake valve.

Rotate the engine until the intake valve has just finished closing. At that point, the exhaust cam follower is directly opposite of max lift on the exhaust lobe. Set the exhaust valve.

Do it this way and you don't have to find any TDC, remove spark plugs, etc., and the lash is set on the base circle of the cam.