yanmar 240D

[Ed Wells]

I just purchased a 240D that has been broke down for 4 years with a blown head gasket. I replaced the head gasket following the instructions in a repair manual which suggested I coat the gasket. I used copper coat.

While in the motor, I replaced the rings, rod bearings, and valve seals. I broke the glaze on the cylinder walls with a hone. The sleeves were not worn but there was some pitting in the no, 2 cylinder due to water standing in it for 4 years from the blown head gasket.

I cleaned the valves, bit did not reseat them.They appeared to be in good shape.The fuel lines have been bled too many times to count and the injectors appear to be working properly.

I haven't checked the timing, but I did nothing to change it. The injector pump was left in place.

When I try to start the tractor all I get is white smoke from the exhaust. I tested the compression and I get 250 psi on the no. 1 cylinder and 200 psi on the no. 2 cylinder. Since the rings are new and not seated, is this sufficent compression to start the tractor? Does anyone know what the compression should be on this tractor. This information is not in my repair manual and I haven't had any luck finding it on the internet.

 

[kenmac]

Don't hold me to this . But, I'am thinking compression should be in the 400 & up range to start your engine. 400 being the lowest

 

[Ed Wells]

Thanks for the information. This supports what I was thinking. My problem is low compression. After reading all the information in the forums on the problem with starters struggling to turn the motor over in a Yanmar, I now realize my starter was turning it too fast for the compression to be correct.

 

[kenmac]

You would think replacing the rings (unless they aren't the correct rings) would have given you the compression you needed.If I had gone that far I would have replaced the sleeves also

 

[tallyho8]

I think I would try pouring a small amount of STP in each injector hole, replacing the injectors, Cranking it over a couple of times WITH the compression release pulled out to get rid of the excess STP, and then try to start it. If the rings are just not seated well yet, this might be enough to get it started so they can wear in and seat.

 

[California]

If you are still working along the lines of simply getting it started to break in the rings:

You can crank it a lot faster using a 50/10/2 amp starter-charger to assist the battery. Only engage the charger's 'start' mode after the engine is already cranking, and switch it off before you cease cranking, to reduce the chance of damaging the alternator.

If it won't start with oil or STP sealing the rings, plus this faster cranking speed, there has to be something else wrong.

I assume you have bled the fuel system, and looked into the intake to verify that the Thermostart element is working.

 

[kenmac]

Not trying to be a smart ???. Did you make sure all the ring gaps were off set on the pistons. I've known guys to build engines & forget to do this & not have much compression. Just a thought

 

[Gizmo36]

That happens a lot.

 

[mark777]

I suspect the ring gap is too wide.