Volvo penta MD22 complete overhaul
As there was little time we decided to overhaul the engine ourselves.
After googling some information about the engine I came to realise this is about the worst engine ever built in history by perkins.
But the problem we encountered was yet not documented on the Internet.
The problem with the engine was water on the head of the engine, so at first we expected the head gasket to be the culprit.
We started by removing the head of the engine to look at the extend of the damage.
All valves were luckily undamaged but as this is a complete overhaul we adjusted the tolerances aswell.
Next to be removed was the oil and the carter.
The engine can be handled best when it is rolled on its back.
The carter can be removed quite easy then.
Motor head has been removed to realign the valves
You can see a little bit of rust already on the cylinders because the came in contact with water.
You can see the carter also contained water because of the rust.
This rust needed to be removed.
Another problem: the starter engine broke because there was water on the engine head.
When starting there was so much torque, the aluminium broke.
I rejoined the broken pieces together and welded it back to one piece.
You can see the weld clearly here.
And now with the complete engine restored.
After failing to find leaks in the head gasket we investigated further, next suspect was the heat exchanger.
Somehow this part leaked all its contents in the exhaust so we had to investigate what exactly failed.
This is why I took my axial grinder to open up the top of the heat exchanger.
(NOTE volvo penta thinks this part is worth 3250 euro's ex V.A.T. I personally think they are totally crazy to charge such amount for a piece is (badly designed) aluminium)
Now grinding the top of the exchanger.
The inner cooling system is clearly visible now, the water is contained above the exhaust and intake tubes.
After pouring some water in the exchanger the exact problem came to light.
You can clearly see the aluminium corroded ( you would expect a sea worthy engine to outlive more then 15 years) but because this part is so badly designed salt water can sit between the gasket and the heat exchanger.
and corrode the aluminium.
(I Really don't know why any sane person would design anything like this (any other then reducing the life expectancy of an engine!))
I tried to restore the aluminium with my tig welder but the aluminium is so polluted by corrosion I was unable to establish a good weld.
Next thing I did was just grinding off the flange to look at the extend of the corrosion, as you can see we now have clear shiny aluminium.
This is the sawed of flange, as you can see it has holes where the leakage originated, this is aluminium which is designed in such a way this reduced the life expectancy of the engine.
Again this is to my knowledge completely unnecessary and only introduced by designers to have you buy parts when the aluminium is gone due to corrosion (extremely expensive parts 3250 euro's ex V.A.T.)
Next step , I started to recreate the flange.
I sawed off a piece of aluminium (costs about 3 euro)
Now milling a hole for the exhaust.
Drilling a few holes for the mounting threads.
And welding the part to the exhaust. ( total costs: 30 euro)
The completed weld.
Now the top has to be reinstated.
And I wanted to test my welds so I plugged up all holes.
I filled the heat exchanger with water.
Then compressing the exchanger to about 2.5 Bar pressure and letting it stay on pressure for a while.
A nice view of the fixed part.
The pistons needed new compression rings because of the water, we first removed all rings and ordered new ones.
Then we started polishing with waterproof sanding paper.
The difference between an polished and unpolished part is easy to spot :D
The Cylinders needed some service too, so we honed the buses till it was nice any flat once again.
after most imported parts were repaired we started painting the engine.
And all small parts :D
We reinstalled all pistons
The pistons feel right at home.
We closed the carter with some special carter seal which can endure high temperatures and oil.
We lost the gasket fixator so I recreated a new one.
Now the head is once again installed on the engine.
And the heat exchanger is bolted to its place.
The air intake is installed
All zero positions have been set so the timing belt can be installed at a later point.
The oil pump needed a new gasket so we cut one.
All pieces which don't need a new coat of paint are taped.
Final screws are inserted
And now the final coat of paint is applied.
Looks like a new engine :D
and sure we broke a piece of the fuel return line, this is brass so I didn't feel like welding it.
So I created a small replacement part and installed it on the fuel return line . :D problem solved:D
I also broke the pulley of the water maker, but luckily only one belt was needed so I removed one pulley ring.
And once again the motor is back in its place , ready to run once again! :D