HELP KAD 43 revs to 2600 then drops

[BruceK]

I must be the only one that thinks running the engine under no load at intermittent intervals through the winter is better than not running at all. I understand it's not great for the oil but I tend to change that at the beginning of the season rather than end for this reason. I think bore glazing is over hyped in this scenario. I think you'd have to be really abusive in this respect to glaze the bores. A 30 min run every second week seems to keep the gremlins at bay. Certainly when I put my boat on the hard over winter and the engines are not touched at all, all sorts of gremlins pop out in the first week or two of being back afloat.

 

[petem]

Anyway I’ll change the fuel filters tomorrow.

Unless they needed changing anyway, I'd be inclined to leave it as it is and save the fuel filters for an emergency.

 

[petem]

I must be the only one that thinks running the engine under no load at intermittent intervals through the winter is better than not running at all. I understand it's not great for the oil but I tend to change that at the beginning of the season rather than end for this reason. I think bore glazing is over hyped in this scenario. I think you'd have to be really abusive in this respect to glaze the bores. A 30 min run every second week seems to keep the gremlins at bay. Certainly when I put my boat on the hard over winter and the engines are not touched at all, all sorts of gremlins pop out in the first week or two of being back afloat.

I think the issue is that allegedly the KAD44's have low oil pressure at tickover. Whether this matters in the grand scheme of things I don't know.

 

[BruceK]

I think the issue is that allegedly the KAD44's have low oil pressure at tickover. Whether this matters in the grand scheme of things I don't know.

I cant comment with fact but I find that incredulous. My KAD42's do indeed drop oil pressure at low revs but this is from 60 to 35. However 35 is plenty to keep the engine lubricated and not bust up a bigend or cam at tickover revs. I really struggle with the concept that at tickover on load and tickover on neutral will make one iota difference to oil pressure and if Volvo ever released an engine that seized up while you were pootling round the marina and harbour their business would go bang.

 

[DavidJ]

Unless they needed changing anyway, I'd be inclined to leave it as it is and save the fuel filters for an emergency.

Good point. I should have been carrying spares anyway.
Sitting on the back of the boat in the sunshine eating langoustines (probably from Scotland) and thinking the last thing I want to do is a filter change so good call.

 

[Momac]

I cant comment with fact but I find that incredulous. My KAD42's do indeed drop oil pressure at low revs but this is from 60 to 35. However 35 is plenty to keep the engine lubricated and not bust up a bigend or cam at tickover revs. I really struggle with the concept that at tickover on load and tickover on neutral will make one iota difference to oil pressure and if Volvo ever released an engine that seized up while you were pootling round the marina and harbour their business would go bang.

The kad44 (and kad300) potential problem, as I understand it , is thought to be slightly poor adequacy of oil supply to the valve gear at slow speed running. I think this is at one end or other of the engine. the kad44 (and kad300) is a 24 valve engine and this oil supply at slow speed not a problem with the 12 valve kad42/43. the kad44 and 30 are also much more in need of valve clearance checking and adjustment every 200 hours while the other engines in the same range can go hundreds more with no need for any attention.
With the exception of this , pootling around at slow speed isn't a problem for the AD and KAD engines generally although I do find my kad32's run all the sweeter at slow speed after a run at the sort of the 3000rpm or so speeds they were designed to be run at .

 

[BruceK]

The kad44 (and kad300) potential problem, as I understand it , is thought to be slightly poor adequacy of oil supply to the valve gear at slow speed running. I think this is at one end or other of the engine. the kad44 (and kad300) is a 24 valve engine and this oil supply at slow speed not a problem with the 12 valve kad42/43. the kad44 and 30 are also much more in need of valve clearance checking and adjustment every 200 hours while the other engines in the same range can go hundreds more with no need for any attention.
With the exception of this , pootling around at slow speed isn't a problem for the AD and KAD engines generally although I do find my kad32's run all the sweeter at slow speed after a run at the sort of the 3000rpm or so speeds they were designed to be run at .

Everyday a school day but I cant help feeling that is a serious shortcoming. I have to ask is this internet lore or acknowledged fact. I have a couple boats in my crowd with 44's and when I lead them down the Menai at tickover I dont want them moaning that I helped destroy their engines for them.
Yes I would never advocate constant low revs, but my distance split is about 1/3 @ displacement 800-1400 rpm to 2/3rds @ 3000 rpm and above with the last 10 miles home across the Bay being a charge followed by 20 minutes at displacement down the channel. However as a time split it's about 50-50

 

[Momac]

Everyday a school day but I cant help feeling that is a serious shortcoming. I have to ask is this internet lore or acknowledged fact. I have a couple boats in my crowd with 44's and when I lead them down the Menai at tickover I dont want them moaning that I helped destroy their engines for them.
Yes I would never advocate constant low revs, but my distance split is about 1/3 @ displacement 800-1400 rpm to 2/3rds @ 3000 rpm and above with the last 10 miles home across the Bay being a charge followed by 20 minutes at displacement down the channel. However as a time split it's about 50-50

Don't fret about it .
River boats perhaps but not the use you describe.

 

[BruceK]

I'm not. I think that story is internet bollox repeated as truth.

 

[[2068]]

I'm not. I think that story is internet bollox repeated as truth.

It's not internet bollox - several owners have modified the oil feed to the valve train to improve this.
It's only an issue if you are running at very low or idle speed for hundreds of hours on end on the river.

 

[BruceK]

It's not internet bollox - several owners have modified the oil feed to the valve train to improve this.
It's only an issue if you are running at very low or idle speed for hundreds of hours on end on the river.

Would you concur then that a half hour run to temp every other week during the winter layup would have no detrimental effect.
Not wanting to be contentious but I've seen several owners throw ad hoc solutions to their boats based on internet lore. Does Volvo have a say on the subject? i.e. Is there anything in the Book of Words or any dealer published confession that KAD44 have a oil pressure issue?

 

[[2068]]

Is there anything in the Book of Words or any dealer published confession that KAD44 have a oil pressure issue?

No, but VolvoPaul said it was true, and that's good enough for me.
Running for half an hour or so isn't the problem - it's boats that spend their entire life at idle speed on a river.

 

[BruceK]

I'd concur that any highly blown engine would not be my first choice of engine on a river boat, that goes without saying, and even then it would have to be severely abused as such before it showed any sign of ill effect. Back on topic with Petem, there isn't an issue with oil pressure to bring the engines to temp, would you agree? There are some negatives but the positives outweigh them, or no?

 

[Assassin]

I cant comment with fact but I find that incredulous. My KAD42's do indeed drop oil pressure at low revs but this is from 60 to 35. However 35 is plenty to keep the engine lubricated and not bust up a bigend or cam at tickover revs. I really struggle with the concept that at tickover on load and tickover on neutral will make one iota difference to oil pressure and if Volvo ever released an engine that seized up while you were pootling round the marina and harbour their business would go bang.

With respect Bruce I think you may inadvertently be throwing in a red herring here, let me explain.

Oil pressure is little more than an unreliable indicator and the crucial bit is actually oil flow or the quantity of oil flowing at a given speed and this is for good reason, if you block an oil or any other pressurised pipe you will get pressure up to the blockage and nothing beyond it so you still have pressure and no flow, with low pressure you have low pressure and whatever oil flow the engine oil pump is producing and if the flow is more than adequate then it does its job without high pressures.

 

[Greg2]

It's not internet bollox - several owners have modified the oil feed to the valve train to improve this.
It's only an issue if you are running at very low or idle speed for hundreds of hours on end on the river.

+1
It has been known for years and there has always be talk of a ‘fix’ to improve lubrication at low speeds as you describe funnily enough it came up on the Sealine Forum this week and DB Marine at Cookham do the ‘fix’ apparently.

 

[petem]

I'd concur that any highly blown engine would not be my first choice of engine on a river boat, that goes without saying, and even then it would have to be severely abused as such before it showed any sign of ill effect. Back on topic with Petem, there isn't an issue with oil pressure to bring the engines to temp, would you agree? There are some negatives but the positives outweigh them, or no?

Bruce, what's your logic for running the engine "to temp" as opposed to running them for a minute or so which would get the oil and coolant circulating and the belts turning?

Plus I'm still waiting for a verdict on my idea of turning the engines over until oil pressure resumes without firing them up.

 

[Scubadoo]

Bruce, what's your logic for running the engine "to temp" as opposed to running them for a minute or so which would get the oil and coolant circulating and the belts turning?

Plus I'm still waiting for a verdict on my idea of turning the engines over until oil pressure resumes without firing them up.

I think that is to with condensation in the engine if run just for a few minutes, best to get the engine (oil) up to temperature, so for me it would be at least 20minutes, same for cars not regularly used.

 

[BruceK]

ahhh, this is a minefield. Firstly I know that for instance in the car world running your engine to warm it up is considered to be damaging for a number of reasons and unnecessary and it's much better to just drive it gently to get to temp and that would be exactly the same for the boat engines too. Much better to just take the boat out and gently run to temps. For me that's not so easy as to single hand a sports cruiser on a river mooring running at 4 knts is not possible. So lets get that out the way first. Until the engine reaches roughly 40C combustion is rich and dumps all sorts including moisture into the engine which is not good and positively harmful. I run to temp in the hope I am burning off some of this moisture and deposits out. Now, when I say run to temp the engine coolant will probably not get to 80C but oil temp lags behind coolant temp so I run the engine a bit longer to get the oil to temp.
Why run the engine at all. If I was in dry dehumidified and temperature controlled storage like a classic car over winter I would not. But a boat engine sits in a humid wet environment so in my mind requires a different set of rules. So it's a juggling act of which does less harm and most good out of two poor options and I lean toward running the engine rather than not.
Your proposal of running the engine on the starter motor has the benefit of not adding any impurities to the oil through poor combustion, however it wont remove any condensate either. My only issue is I think you will do irreparable damage to the starter motor running it long enough to fully circulate oil round the engine and I question whether it will be sufficient, especially as you are not fuelling, to lubricate the cylinder bores.
Finally the engine ancillaries like the raw water water system getting a good flush through to help prevent settling of any sediments and particles in suspension and flash rust on bearings and brushes in starter, alternator, turbo fan blade / housing etc from creating a erosion point that will shorten their life.
I appreciate it's an emotive subject and arguments can be made from both angles, these are just my reasoning's and beliefs. I have observed my own engines fair much better being run this way than left standing over winter. When they have been left standing on the hard I always have some gremlins creep out. Surprisingly, a lot of electrical gremlins too, though why running and engine should affect these is beyond me, just an observation.

 

[petem]

Thanks Bruce. I do wonder however if a day after you've left the boat whether the moisture in the 'new' air has condensed again making you no better off.

Incidentally, on the last boat that we had I left it in the water for one season and ashore for the other. The pontoons in the marina were gated but the hard wasn't and we were consequently broken into damaging the companionway door. That would have been a £2k repair as the whole helm console has to be removed to change the door. It would be even more of an issue now as the green coloured perspex is no longer available.

 

[BruceK]

Possibly, and I could well be 100% wrong. I'm just saying what I have found works for me and why I believe it works.
Bit like leaving a pair of pliers on the boat. So long as I use and move the handles about on the odd occasion it doesn't seize up. Leave for a while and they seize up. I think mechanical items designed to move enjoy being moved.