The reason that diesel
engines don't like to start in the cold is that they can't build enough heat in the cylinders to fire. Heat comes from compressing air, a little bit of friction and any supplemental heating
sources. Heat is lost
through the exhaust
and block. If your compression
is low, you won't generate as much heat. If your cranking speed is slow, you won't generate much heat because leakage past the rings and valves is much more important the slower you go. If your engine
is cranking slowly, make sure that your starting system is in good shape, your connections are clean, your batteries are good and you are using the right oil
. Friction is basically negligeable and something that you won't have a lot of control over unless something is wrong.
Heat loss is also hard to change. The most important thing here is the cylinder volume to surface area ratio which is much better for larger engines (and incidentally part of the reason why big engines tend not to have supplemental air heaters for starting). The only practical way to change heat loss in a diesel engine without a redesign is to put a block heater on it and make the temperature differential lower. Electric
block heaters are very easy to plumb into a fresh water
cooled engine but they require shore power
. Salt water
cooled engines require the use of an oil pan heater instead of a block heater. If you don't have AC power, you can use a diesel fired one like an Espar or Webasto.
The other option is to do supplemental heating
of the in-chamber air. This can either be done in the chamber (glow plugs) or in the intake manifold (grid/intake heaters). Adding glow plugs to an engine not designed for them is really difficult since you need to drill through the head an not hit anything. In addition, it affects performance since you are changing the combustion chamber a little bit. With some IDI engines, it is possible to add them but I don't recommend it despite the fact that they are more efficient as a starting aid. This leaves grid heaters which work reasonably well and are not too hard to install. The best type are flat plate type although ones that go in through a tapped hole are available. All of the B series Cummins in Dodge pickups have them and the Duramax from the LBZ on uses them. I have used the Cummins ones as a retrofit on another engine but we were building a new intake anyways. That engine uses 2 but just one of them will be more than enough for an engine like yours.