No COmpression on VOlvo MD2020

[Sea Fever]

Hi,

My friend has a MD 2020 and has not started the engine in 2-3 years. He just started to check it and finds thet the engine turns but does not start. It seems that there is no compression. Can anyone help? What are the most likely causes and some things he should check?

Thanks.

 

[kloudie1]

No Compression

First, make sure that the compression release is not engaged. Next, close the seacock for the seawater to the motor and remove the inlet hose to the raw water pump. Now check for stuck valves.. or for valves that are too tight. If buddy is an engine guy, he can pull the valve cover and rotate the engine and watch the valves operate. Any that are open (down toward the head) and not returning are stuck. They can be gently persuaded to open a bit further with a screwdriver or other lever, then released.. If you do this a few times, the stuck valve (s) should free itself .. WD 40 can be applied to the valve stem where it enters the guide (inside the valve spring) to help free it.. (remember this is a diesel and will start on WD 40 if it gets compression)
If the valve clearance is too tight, there will be no compression either .. This requires setting the rocker arm clearance to the correct dimension..
In a nutshell, feeling the rocker arms as the engine is slowly rotated will tell you either of these problems..If the rocker never gets slack in it the valve is too tight.. if the arm gets large slack, like ¼” or so, the valve is stuck.
If you are not sure about this, call in a diesel guy to help..

 

[EatDrinkHealthy]

Stuck rings

If the engine has not been started in 2-3 years and was not properly fog before storage, it is likely the rings are stuck. You can usually unstuck them by lots of penetrating fluid. WD40 is not a penetrating fluid as WD means Water Disperse. You'll need Liquid Wrench or something like that.

Squit the penetrating oil into the cylinder to soak the cylinders over and over for a few days. Hand crank the motor slowly until you feel suction. Make sure you change oil and filter again after she fired up. Penetrating oil is not good for o-rings.