D.C. 3.5cc DIESEL REBUILD

Here we have another D.C. manxman 3.5cc diesel engine sent in to us from a client in Australia. His request was to please make it mechanically as good as it looked and could we please rectify the missing anodized spinner nut. Well here's the engine as we received it, looks good on the outside apart from the obvious missing spinner nut, however the compression was also missing, completely, Oh dear, well never mind I think we can sort all of those issues without to much problem. 

Well let's get it stripped down and assessed for repairs.

 

Once we had a good look over this engine we found that the con-rod was also needing to be replaced as both ends were ovulated. The cause of the ovelated rod was a very poorly fitted gudgeon pin which had flogged out the piston hole and the little end and just for good measure had created a small groove in the bore, hence no compression.The clear plastic tank has also suffered from ageing and has become distorted so we will manufacture a new replacement fuel tank as well.

 

First step was to make a replacement con-rod and then move onto making the piston and contra piston blanks.

Now we'll move onto lapping the liner and preparing to machine and fit the replacement piston and contra.

 

New piston and contra made and fitted up, now lets assemble the rod and new gudgeon pin etc.

 

As with a lot of the D.C. engines there is excessive end float in the crank/prop driver department so we will make a thrust washer to place between the crankshaft front face and the crankcase to realign the inlet port hole correctly with the venturi hole and eliminate the unwanted end float at the same time. It should be mentioned that a small amount of end float is desirable in this style of engine as it allows for the expansion of the case etc as operation heat increases, but to much will bring disaster to the engine internals.

 Here's the crank thrust washer made and ready to fit.

We fitted up a prop to tighten the prop driver to as in use conditions to confirm that the correct amount of free play was till there without being excessive.

Here's the engine reassembled and awaiting the next step.

Now we'll make the correct tank mounting bolt.

And voila one nicely made slotted cheese head 6BA tank bolt.

Next we'll clean and refit the N.V.A and machine up a replacement spinner nut.

 N.V.A all clean and refitted, now we move onto the spinner nut and the replica tank.

 Spinner nut all sorted.

Now its onto the replacment fiuel tank.

 

All finished and ready for the fuel to be added.......................