www.railforums.co.uk
There is a market for MTU engines for (marine) re-use, not sure if there is much demand for old Paxman units
Wrong way round. The lack of preheat makes a VP harder to start when cold.
It does.
But the need to keep an MTU ‘warm’ presumably makes them a more difficult prospect for irregular use in preservation?
You only need to keep it warm to avoid penalty under the maintenance contract with MTU; an MTU will perfectly fine when cold. Preservation groups aren't going to have that contract in place - it is far too expensive.
No, the lack of preheat may make actual starting harder (turning it over for long enough and it will fire eventually, batteries permitting) but the MTU will not start without preheat, which means if you shut them down you may end up stuck unless you can bypass it.
It’s nice to watch and hear though.
You can bypass it, we do it semi regularly here in the winter. But it takes 100 hours off the engine life and there is a fine from MTU for doing it. Unfortunately there's no choice sometimes.
Sorry, your first sentence is misleading. The MTU WILL start without preheat - if you have the preheat bypass switch turned on the cubicle. Which is where all the pres MTU's have been since they were acquired.
You are wrong. How do you think preserved MTUs are started? I can categorically state that a cold MTUs can be started - I have seen it happen on several occasions.
I did say unless you can bypass it, which someone has confirmed that you can.
Ok, engine that are preheated will be easier to start, that's what I'm implying. I was under the impression that MTUs required preheat to start unless you had a way of bypassing that, which has been confirmed that there is a bypass.
To be honest, the MTU is embarrassingly easy to start cold. The reason for the pre-heater is historical - MTU is effectively Maybach who always pre-heated their engines. 41001 had pre-heat installed but that was a flame thrower (diesel powered) and only reliant on a bit of battery power to get the pump running, which is a much better proposition than using 3 phase which in preservation is a luxury most don't have. Worst power cars to start cold are the VP185's - worse than Valenta by some margin. They try and hold back the fuel too much - which works fine when warm for non claggy start up - but actually doesn't provide enough fuel to get the engine to fire. Complete opposite of a Valenta where you hold the fuel rack back to stop it over-fuelling so much.
Ok, thanks for info. I appreciate it's a German thing as almost all German diesels seem to be connected to a shore supply when stabled and shut down. I didn't know if start circuits contained a switch that prevented starting below a certain coolant temperature. Assume it does but it's easily bypassed?
It easily bypassed - turn a switch 90 degrees on the cubicle. As long as you don't have a contract with MTU then you're fine. If you have a contract with MTU then collect 100 hours deficit on your engine hour meter.