To warm up or not to warm up?

Should I?

  • Just get on with it

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  • Fein an ankle injury

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MYStargazer

MYStargazer

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Just wondering if diesels prefer to be warmed up under load, i.e. switch on and head out there, or whether it's preferable to let them warm up a bit.

I have a couple of elderly turbocharged Ford Thorneycrofts (Dover type) in my Weymouth 32, but would the approach be different with newer engines?
 
Ijust fire up ,leave ticking over whilst faffing with string and fenders, cast off mosey through the 5 knt speed limit. 1/4 on hour has passed engine is half way to working temp, another 5 mins at half throttle then of we go at an amazing 14 knts!
 
No idea on heat. But I just check the oil has got up to pressure then we are off. If its hit its normal point I know all the top of the engine has some lubrication before I take the revs up.
 
I was taught that most wear on the engine occurs during the period it take for the engine systems to get to working temp, admittedly modern developments in materials, including lubricants have reduced this wear process however; If the workload is reduced during this period then less wear will occur what ever that state of technology! I think most let it rip merchants will have sold on before this wear becomes too apparent. Most documentation I have seen prescribes to the practice of reduced loading until engine is at "OPERATIONAL" temperature. Love yur engine and be gentle when it is cold, it will return such affections over the long term!!
Neil
 
Advice on cars some years ago was to move off immediately, but be gentle until the engine warms up. I start mine, leaving it on a fast idle while getting ready, then off we go, but at no more than half throttle until everything's properly warm.

Any glazing is removed by a good flat out blat for a few minutes every month or so. Does wonders for the the injectors, too - you should see the cloud of smoke for the first 100 yards, but it soon clears and the engine runs smoother and starts better afterwards.
 
The handbook for my Iveco says the following:

"Set throttle to 3/4, start the engine,throttle back to neutral, after one minute start moving the vessel at slow speed. This is the only way to warm up the engine."
 
It's not just about pressure, but also temperature. Oil temperature that is.
With a car you need to get the oil to 45-50 degreesC before going over 3-4000rpm (it depends a great deal on the engine). But running under a light load at medium revs will help get the temperature up more quickly.

I used to be an ambulanceman when Ford Transits used the V4 and V6 engines. Cold starts and thrashing straight away meant that some motors only lasted about 12,000 miles.

Many claims are made for modern synthetic oils, but relying on them to avoid bearing damage is not a good idea.
 
We are talking about boat engines that float on UK water I presume. Not the same as a high performance light weight engines standing in a frozen street.

I remember cycling home in -27C but I doubt an engine would ever see less than 10C in UK waters. Assuming the time to check the oil and water flow and the fact that boat engines hardly go to 3000rpm in the first few minutes I doubt there is a problem.

OK now we will get the list of people who regularly need 3000rpm to get out of their berths safely. But...

It is like when they once complained about a memory chip that would not work at -25C but was fine at -50C. It was to be used in a torpedo! Innocently we asked "Isn't the water a bit hard at that temperature?"
 
Thanks, all.

The idea seems to be fire-up, faff for a few seconds, tickle out of the harbour and then go for it.

Just put this into practice steaming out of Palma harbour and round to anchorage at Puerto Portals. I dread to think what damage I did going down the French canals, but at least there were a few opprtunities to let rip on the river stages.
 
Not talking about high performance engines (Ford V4 commercial?)

Don't forget that diesels run at compression ratios routinely 3 times that of petrol engines. 20:1 is not unusual. That's one hell of a percussive load on bearings, so nice warm oil is to be recommended. Oil temperature guages aren't just for spotting overheating.
 
My Perk 4-107 ..... I start it on 1/3rd .... as soon as it sounds clear from start diesel ... I throttle back. By time I have put engine cover back ... I go to cockpit and give it a 1/2 throttle kick ahead, then 1/2 throttle kick astern ... as test of gearbox and throttle link. Let go moorings and up to max 1/3rd throttle for exit of marina and speed restricted area ... then its a good blast before shutting down.
 
By the way glazing is a myth in modern diesels warm the engine up to operating temp however long it takes before putting it under load. .
 
I normally start engine, check water (coolant) flow, test forward/reverse gears. Then release moorings, save one. If necessary radio for lock out. Release last mooring, and away I go
 
People keep telling us what they do. Doesn't mean it's the best for the engine. Glazing bores leads to a slight lack of compression. It won't happen at low temperatures, so warming up an engine and it's oil is not detrimental. Knocking the bearings out, however, is bad for a motor.
 
A coupe of things . . .

Firstly, IMHO the belief that running at full throttle will in any way decrease the presence of glazing is false. The only way that glazing can be removed is by honing the cylinders.

Secondly, in the true sense of the words, boat engines never experience "full load" which, again IMHO, is reserved for automotive applications in which the load on a drive trian is positive and measurable unlike a propeller that always has a goodly percentage of slip.

I tend towards the earlier post where Iveco recommend: start up, check the systems (oil pressure, water flow) and then trundle out of the marina using 2000rpm or less until warm.

I don't do this because I'm scared of glazing or any other percieved hobbly gobblys, I just want to spend more time sailing and less messing about.
 
Yanmar manual for the JH(2) series says to warm up by letting engine tick over for five minutes.
The actual quote is "Warm-up the engine at idling speed for about five minutes after starting to permeate the lube oil to all parts of the engine. If the engine is not warmed up, there will be excessive wear of the moving parts."
 
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then trundle out of the marina using 2000rpm or less until warm.



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My old thumpers redline at 2000rpm, and are limited to 2300! Thorneycroft (people so helpful they almost make choosing the brand worth it) tell me that it is impossible to overrev these engines. They do sound SO good over 2000 with the old Holset turbochargers, though...

Given the fine that Magnum was said to have been given (EUR 000's for speeding in Palma harbour), not trundling is not an option until they're warmed anyway.
 
In the Volvo workshops I have worked for we ALWAYS waited until we had 80C before going over 2000 rpm and letting the turbo into the game, that way you know the oil is warm and circulating nicely. Cold oil will naturally indicate high pressure, but that doesn't mean all the bearings are getting a good flow through them, especially the crank,camshaft and turbo so be kind to the engine while its warming up by not making it work too hard.
A bit like an athelete limbering up before a sprint.
 
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