Volvo MD2B

[Ronbye]

I have a 1975 MD2B engine that I completly rebuilt approx. 7 years ago. I have some questions that maybe someone can help me with.
1. My engine is equipped with a DynaStarter. What is the charging capacity and how hot is it's normal operating temperature.(I can leave my hand on it while running for 10-15 seconds max.)
2. My engine when at operating temperature is showing blue smoke in the exhaust. When cold, there appears to be unburnt fuel coming from the exhaust. Is this normal. I am not losing any oil, and the engine is very reliable.

[Blue Eagle]

Hi Ronbye,

I have an MD11C of 1976 vintage that I rebuilt last year, so Ill try to answer your question by reference to that:

In terms of the dynastarter, the honest answer is I dont know - mine is fitted with a starter motor and separate dynamo (now alternator). My suspicion is that it will be very inefficient though - Im guessing, but maybe 10 - 20 amps maximum. I dont know the normal operating temperature for these beasties either, but if I were you I would a) fit an ammeter in-line to check it is working at all, just after starting, when the batteries will need most charging, and b) contact Volvo in Sweden to ask them. Their technical department are pretty helpful once you reach them.

The smoke: Now, I have the same problem. Because the engine is purely compression-ignition and has no glow plugs (which is part of what makes it cast-iron, bulletproof reliable) it runs a little rich and yes, it expels a little unburnt fuel out of the back. Im surprised at the colour smoke you say you are getting though. Unburned fuel, in an engine of this vintage, gives greyish white smoke, any blue in there, and youre most likely burning oil. I say "in engine of this vintage", because in turbocharged engines, greyish-white smoke can also be a sign that the turbo bearings are shot, and leaking oil which vaporises in the turbo on the low-pressure exhaust side. Our old Volvos dont get hot enough to flash oil off like this.

If youre certain that oil isnt the problem, Id consider checking the air filters which may be partially blocked causing incomplete combustion, and having the fuel metering unit, and injector(s) overhauled by a bosch service agent.

Best regards,

Blue Eagle

[Ronbye]

Good point about the air filters. I have a spare engine with another set of air filters. I will try this first, and while doing so, clean both sets of filters. I suspect that the fuel adjustment could be off or the injectors are in need of service.

[Windborn]

Ronbye,

My One Ton has '75 MD2B, and I had a similar "blueish" smoke issue. Cleaning the air filters took care of the problem.

[Ronbye]

This is great. The information and assistance I get from this site is second to none. Thanks to everybody.