Join Date: Sep 2006
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Well, there are diffeering opinions on this one.
I have got one, a 1977 MD17c, now 31 years old.
The motor is very well built indeed, but, as I have said many times, the price of spare parts is absoutely shocking. I will never buy another Volvo. Never.
The engine has spent 27 years in salt water, and the last 4 in fresh water.
In 1997, I had to split the barrels from the liners as one was leaking past an O-ring. It was corroded, but not too bad, and it went together ok, and has run well since.
If in fresh water, you can just about forget about corrosion as cast iron and fresh water virtually ignore one another chemically. Freshwater does freeze readily though, so beware frosts. I learned that one the hard way, at -14 degC, and a cracked block.
I thought of converting to fresh water cooling, but it needed an electrical pump as extra, the cost was high, the materials looked thin, and the coolling circuit diagram was far more complex. Raw water has a very simple circuit.... one pump.
Personally I would leave it. If it begins to take water in the oil, look first to the O-rings at the base of the liners. I will be surprised if the water jacket rusts through. It is rather thick on what is a very heavy engine.... about 780 lb on the MD17C.
Also, it is a very well-built motor. Just the spare parts is a very painful memory for me and I will never again give Volvo the chance to charge me £1300 (now $2600) for an exhaust manifold, then in 1997.
If ever you have to split the motor, send me a PM. I have some lessons learned in the one. Piston oversizes are available from Mahle (then £72 each) if you have to re-bore. Volvo will not sell them to you..... you have got to buy the liner kit (then £300, for me x3), and it is about 3 times the cost of a re-bore and new oversizes.
I found the gearbox reliable, if you always shift into gear at idle, and change the gear oil every now and again. If the final drive seal fails, again PM and I will steer you through that learning curve, three weeks long, but sealed in the end.