DownWest
Well-Known Member
Stu, if that is correct, then he is lucky it is only the gasket..
Volvo MD2020 - Head removal advice needed
- Thread starter Jokani
- Start date
Heckler
Well-Known Member
indeed
NorthUp
Well-Known Member
You still tested them though!
Paul, my line of thought was based on the poor starting and smoke, followed by an apparent recovery after 30 secs running. Traces of water in the oil can be due to the engine backfilling from the exhaust if there is excessive cranking with the seacock open, coupled with poor exhaust design.
I would have explained this possible scenario earlier, but bailed out when the thread turned nasty.
As always, the OP never gives all the info required, it has to be teased out.
You obviously had prior knowledge of the engine and its history. You do not have a clue about me or my cv.. chill!
To the OP, well done on tackling your first cylinderhead removal, I'm sure it will all come back together successfully!
PaulRainbow
Well-Known Member
I only tested them so that i could honestly report back to the forum with the results of the head removal.
My only prior knowledge of the engine is from reading the original thread on this forum, when the engine was first rebuilt. Gary recently moved his boat to the same marina as me, so i've had a look at a few things for him over the past two weekends, including some guidance on the head removal.
Jokani
Well-Known Member
All the help and advice recieved in trying to help me move forward is much appreciated.
On purchasing the boat, when the old MD2B was in place, it had issues, I had that engine professionaly looked at by a marine engineer, he advised the existing system was in place was dangerous collapsing exhaust amongst other things. He fitted new exhaust pipe and the muffler/waterlock in the rear locker. I installed the MD2020B and re-used the existing exhaust system, presuming it was all correct.
It is clear what you say is absolutley correct Stu, I will follow your advice and rectify the exhaust system. Thank you.
Paul, you help over the last 2 weekends has been invaluable, and much appreciated, thank you.
You sound more confident that I do ;-) I hope that the next time I need to advise, it is not engine related.
Yep, in some ways it does sound like I have dodged a bullet, lots of work to do, I'll crack on.
On purchasing the boat, when the old MD2B was in place, it had issues, I had that engine professionaly looked at by a marine engineer, he advised the existing system was in place was dangerous collapsing exhaust amongst other things. He fitted new exhaust pipe and the muffler/waterlock in the rear locker. I installed the MD2020B and re-used the existing exhaust system, presuming it was all correct.
It is clear what you say is absolutley correct Stu, I will follow your advice and rectify the exhaust system. Thank you.
Paul, you help over the last 2 weekends has been invaluable, and much appreciated, thank you.
You sound more confident that I do ;-) I hope that the next time I need to advise, it is not engine related.
Yep, in some ways it does sound like I have dodged a bullet, lots of work to do, I'll crack on.
Jokani
Well-Known Member
Stu, having thought about this most of the day, and I owe you an apology! I remember now, you said a long time ago that the exhaust system could be the problem, you may even have told me back when the prev engine was still installed, which also had problems.
Unfortunately, I discounted what you said, on the basis that the exhaust system including waterlock/muffler was just about the only thing I have that was professionally installed, and I asssumed it had to be OK. I wish I had listened to you more back then, and not made false assumptions, my bad!
Maybe what threw me most is that I do have a waterlock fitted, it's just installed at the wrong end of the exhaust, and I just didn't realise that until today.
Googling for 'westerly centaur engine' images, I have struggled to find one without the waterlock at the right end, some examples:
Off to beat myself up a bit more, but (expensive) lesson learned, don't make false assumptions, and I'll try and listen better next time!
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VicS
Well-Known Member
The Vetus on line catalogue gives useful guidance on location and sizing of a water trap also on fitting an anti-siphon loop in the sea water cooling system. See pages 83 and 94 at http://pdf.nauticexpo.com/pdf/vetus/vetus-catalogue-2017-2018/21508-99645.html
( but note that the anti-siphon loop on a MD20n0 series has to be fitted between the water pump and the HE. rather than between the HE and the exhaust elbow
Jokani
Well-Known Member
Thanks, that is a helpful point. I did look at some Vetus diagrams this morning, and was planning to try and install an anti-siphon between the HE and elbow, but if it is sufficient to have one between the pump and the HE, then I already have that in place:
Photo was taken before I fully completed the project, and the anti-siphon valve now vents in to the cockpit.
Thanks again.
PaulRainbow
Well-Known Member
I'll have a look next time Gary is onboard, but it might be easier to fit a pee pipe.
Edit, beaten to it by Garys Pic.
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VicS
Well-Known Member
Yes the vented antisiphon loop can be anywhere in the "system" between the pump and the injection point into the the exhaust ( obviously not before the pump or it will suck air in and lose its prime)
Traditionally immediately before the exhaust injection point but that would require a shed load of ingenuity to do with the MD20n0 series
BUT is that loop of yours well above the water line level? Vetus recommend 40cm ( Beta say 50cm in their installation instructions)
Jokani
Well-Known Member
Yep, definitely have more than 50cm, but given my history, I will double check!
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VicS
Well-Known Member
Fair enough . Just wondered as cannot tell from your picture where it is.
PaulRainbow
Well-Known Member
He said, it's in the cockpit.
FYI, Beta can't make their minds up, they say 50cm in some publications and 30cm in others. Also, it's not a measurement of where the "loop" is, it's where the siphon break is, the two are not necessarily the same.
VicS
Well-Known Member
He said it now vents into the cockpit, not that he has relocated it to the cockpit!
The Beta publication to which I refer is their "Installation guide" which was a separate document but is now incorporated into the "Installation guide and operators manual" for the whole 10 to 115T HE cooled engine range. If they suggest any other figures elsewhere it perhaps emphasis that it is not critical.
The relevant dimension is the location of the top of the loop, Not where the siphon break valve is located. or where the non-valved type discharges. It would not be satisfactory, for example, if the loop was much lower, close to or below the waterline, with the valve itself or the discharge of the non-valved type located 40/50 cm above the wl
Below is the illustration from the Vetus catalog
PaulRainbow
Well-Known Member
Yes, it now vents into the cockpit, as opposed to when the pic was taken. Therefore he has relocated it to the cockpit.
Your Google skills know no bounds. Your skill and experience of diagnosing and fixing engines is another story. It's one thing to Google workshop manuals and post snippets on here, it's another to be able to correctly diagnose a problem, from the symptoms provided, real knowledge and real World experience are invaluable here.
I refer you to posts #9 and #32.
Where would Gary be now ? Still scratching his head having wasted his weekend checking glow plugs and passages.
captainboo
Well-Known Member
I think there is a bit of confusion going on here. He has not relocated the valve anywhere but when he finished the installation the connection from the anti-syphon valve brass spigot goes into the cockpit so in the event of the valve not sealing it will discharge where it can be seen and not presumably into the engine bay.
As Vic stated you cannot tell in the picture where the anti-syphon loop is in relation to the engine/exhaust water injection point etc. but it is definitely not in the cockpit!
The critical dimension as Vic states is the distance that the loop is above the water line, not where the outlet from valve is located. The higher the better so in the event of excessive heeling/high sea state the water cannot flow over the loop of the anti-syphon valve. Ideally it is located close to the centre line of the boat to reduce the effects of heeling.
Mine was originally a valved type in the cockpit locker but I removed the valve gubbins and connected a pee tube which goes some 6 feet to the transom. I now don't have to worry about the valve leaking into the locker and I can tell at a glance that the cooling water is flowing.
As Vic stated you cannot tell in the picture where the anti-syphon loop is in relation to the engine/exhaust water injection point etc. but it is definitely not in the cockpit!
The critical dimension as Vic states is the distance that the loop is above the water line, not where the outlet from valve is located. The higher the better so in the event of excessive heeling/high sea state the water cannot flow over the loop of the anti-syphon valve. Ideally it is located close to the centre line of the boat to reduce the effects of heeling.
Mine was originally a valved type in the cockpit locker but I removed the valve gubbins and connected a pee tube which goes some 6 feet to the transom. I now don't have to worry about the valve leaking into the locker and I can tell at a glance that the cooling water is flowing.
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PaulRainbow
Well-Known Member
You could be correct, i'll have a look at the weekend when Gary is back onboard.
