New BUKH DV48 turbodiesel engine front seal to solve leak. Expedition lifeboat conversion Ep114 [4K]

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EPISODE 114
The diesel engine's front seal was most likely the cause of a slow radial oil leak last year, so given it's 15 years old, probably needs replacing. I enlisted the help of a mechanic to show me how, and also to investigate my rudder stem seawater leak.
BUKH DV48 RME manual links:
Handbook alexhibbertnew.squarespace.co...
Spares List alexhibbertnew.squarespace.co...
Workshop Manual bukh.dk/upload_dir/docs/FAQ/B...
Products mentioned:
561B0706 SEAL FRONT DV36-48 nr2051-
000E4817 GASKET FRONT ENDCOVER DV36-48
Feel free to ask any questions in the comments!
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Thanks to vanguardstorage.co.uk/ for warehousing facilities.

[@AlexHibbertOriginals]

To answer a few repeat comments - we hadn't 100% confirmed the leak was from the seal, we wanted to properly clean the end of the crank shaft of roughness/residue, inspect the old gasket in case that was at fault, and have a general check inside since the cover has not been off in 16 years/since birth. This is the reason we didn't just drill the old seal and hoik it out.

[@kst357]

A cover that doesn't undergo any load but just covers an opening doesn't need to be torqued to its maximum limit. Doing that could cause the gasket to crush & fail, so what you really want to know is how much torque the gasket requires for a proper seal. The gasket material & manufacturer determines how much or little torque is required. It's a good practice to use thread sealant on any bolts where the bolt hole goes through the casting and the area is submerged in oil. The same applies to any bolts which go through a water or coolant passage.

[@AlexHibbertOriginals]

Thanks - and yes loctite was used.

[@ThePaulv12]

Man, I'm a qualified mechanic. Quite experienced by all accounts. I now drive trucks for a living. Don't get too hung up on torque specs. Think practically, If you were out at sea and effected a bush repair would incorrect torque settings cause the timing cover to leak? Of course not. Mostly we ignore torque values except for important stuff like cylinder heads and main & big end bearing caps. Granted, experience gives you a feel for these things, which I see you don't have because of your over cautious approach. That's not to say I'm taking the piss BTW. I have no experience in boats and high Artic trekking so by all measures I think you do pretty well in everything you put your mind to which is better than I can say for myself LOL. As a general principle torque of bolts can be worked out by their size anyhow. If it has a 17-19mm (or 11/16 - 3/4") head then 70-90 ft'lbs.12-14mm head in the 15-40 ft/lb range. Most stuff you just don't need to worry about. People are going torque spec crazy at the moment. It's bizarre. A tip, with 2x machined surfaces you can delete gaskets so long as the surfaces are spotlessly clean. You just use a good quality silicone and prep the surfaces with a razor scraper, Emery, a thorough clean with solvent then a final clean with something like Brakeclean (be careful it ignites in confined places as it's an aerosol pack). For example I have a V12 Daimler. A cam cover gasket blew out. It is a big job replacing those. It was pissing oil onto the exhaust manifold and was getting stupid. As a mechanic on the one hand I hate working on my own stuff, on the other it gives me skills to indulge stupid cars that would send most people broke but I still put it off way too long because I couldn't be bothered. Anyway, after tearing down half the top of the engine, I just deleted the cam cover gaskets, used Permatex grey on spotlessly prepped surfaces and they've never leaked again because there's no gasket to compress or break, causing the screws to come loose. They're effectively glued and screwed in place. It's been like that for 20 years now. You can do this on machined parts, you can't on stamped steel covers to machined surfaces - they need their gaskets. Edit: Change 'principal' to principle to placate a passive aggressive pedant, delete typo. (the vishus thrill I got from there loose of sleep over incorect usige neerly caused me two leeve it like that)

[@zwloki0]

Even with stamped elements you can use sealant only, the key is to coat both elements and wait for about 20 min before assembly. As of the torque settings you are absolutely right

[@AlexHibbertOriginals]

Thanks

[@teeanahera8949]

PS, Principals run schools among other organisations so we’re talking principles in this context.😊

[@the_grand_tourer]

I'm giving the old 3 cylinder Perkins I pulled out the boat my father built (he marinised the engine too), a good old service for the first time in 30 years! Front end seal is one of the jobs. Thank you, too easy to get swamped by manuals and over cautious advise, when some common sense will do just nicely.

[@XMarkxyz]

07:50 Looks like I can use my degree in airspace engineering for a comment, I'm not sure about the pressure theory as a low pressure should help the evaporation and pull the fluid away, personally I would lean towards the air trapping/counter flow theory for a couple reasons: the fluid is in the so called boundary layer region (first 5-10 cm on top of the wing surface) where airflow relative to the wing is slow going from 0 m/s to the speed of the undisturbed airflow above (pretty much the speed of the airplane), so being in a very shallow layer that fluid "sees" just a very small speed difference also we have some adhesion to the skin of the wing; the pooling region are where different panels meet or in general where the surface has irregularities, that probably causes areas of still air in a sort of vortex where the main flow passes over it

[@AlexHibbertOriginals]

I was hoping for something like this to pop up! Thank you.

[@XMarkxyz]

@@AlexHibbertOriginals you're welcome, and it is part of the unavoidable engineer instinct to give his, usually unrequested, opinion obout stuff 😅

[@tyskStefan]

Let me add my 2 cents to the torque spec debate: First of all you are right in that 147 Nm is well beyond what even a grad 12.9 M10 bolt would be able to handle. The commonly used tables for torque specs usually only apply if the bolt is NOT loaded in axial direction. If you torque an axially loaded bolt with said torque it is possible that it will break under load because the preload from the torque is at around 90% 0.2% offset yield stress and sometimes even higher. Also be careful when using high grade bolts - just because the bolt can withstand it does not mean the threads in your part can... Given how these bolts are only holding the flywheel and are therefore pretty much not loaded axially going with the typical torque tables should be fine. A bit lower is usually fine as well, but higher is not a good idea unless you really know what you are doing. Additionally, 49 Nm would be a "torque table" value for a typical grade 8.8 M10, so I am wondering if the "147" was meant to be a "47" instead. The table you showed already exceeds that value.

[@AlexHibbertOriginals]

Pleased your logic matches ours!

[@dcallan812]

Nice, some hatchlings. 👍👍

[@salamander5703]

147Nm looks like the torque for refitting the flywheel, not the cover bolts.

[@AlexHibbertOriginals]

Apologies, I could have been clearer. We needed to do three sets of bolts up, including both you mention. None of the sets of bolts appear to be the sort likely to withstand 147Nm.

[@robina.jensen6114]

Bukh is one of the most reliable marine engines ever made! It's a Danish made engine. Bukh will probaly have the right bolts for sale or there is an typo in the manual. Genuine parts is best. Beta Marine is a Kuboto engine that has been marinefied by Beta Marine.

[@AlexHibbertOriginals]

Thing is, the genuine parts were just OEM parts from SOG with a 0 added to the price!

[@jeremykamel9655]

You are correct in not going to the spec in the book. For one thing, that much clamping force on the gasket is in no way needed. For another, unless they paid for some absurdly expensive costume bolts out of a nuclear reactor then there is no way they’d ever even come close to approaching that torque before breaking for that size bolt. Must be some sort of conversion formula failure or misprint that wasn’t caught by the engineering department manuals editor before printing.

[@ManxAndy]

Good afternoon….👍🇮🇲

[@31144]

Why take the cover off ? Drill a small hole through the front of the seal ( it's a steel case) then screw a short flat head screw into the hole to use as a lever point, better still a small short slide hammer with a screw attached 👍

[@AlexHibbertOriginals]

Cheers - see pinned comment

[@LorenTedford]

Engine work is never any fun.. Hope your doing well! Looking forward to more Alaska Winter adventures some day!

[@MakarovFox]

nah working whit engines is so fun

[@willmv4139]

Any lee coths, if you intend to sleep on the benches, Alex?

[@AlexHibbertOriginals]

The benches are rather narrow (37cm), even for in rougher conditions. There's a proper sleeping platform that spans the gap so you have more space, but can't roll off. The new cubby area in the racking is there for short rests/naps too.

[@jakleo337]

Why not just pry the seal out without removing the cover?

[@AlexHibbertOriginals]

Cheers - see pinned comment

[@Carsonktm420]

Did you try and hide the bottle of wine with a cd 💿 😂

[@AlexHibbertOriginals]

Well spied! But no. It's a rocker stopper instruction label on a piece of card, in front of an old wine bottle full of water I use as a bookend. If it were a lovely bottle of wine, I'd have it front and centre.

[@zwloki0]

None of the torque settings in this case are absolutely crucial, the cover i would torque to max 30Nm The flywheel in this case doesn't transmit any torque and spins with relatively small speeds. What i would recomend is threadlock

[@AlexHibbertOriginals]

Thanks - yes we went beyond 30Nm but held back going anywhere near 100! Loctite yes, was used.

[@zwloki0]

@@AlexHibbertOriginals around 80Nm at the flywheel will is good 👍

[@ysesq]

147 Nm is 108 ft lbs or less than the torque used for tightening the lugs on a car wheel. always follow the manual.

[@AlexHibbertOriginals]

Most car lug nuts are much larger than 10mm, and torque charts I've seen for normal cars are 80-120Nm.

[@ysesq]

@@AlexHibbertOriginals i double checked my BMW M2C manual and lug bolt torque is 140 Nm (105 lbs-ft) as per BMW. BMW 2019 BMW M2 M14x1.25 140 Nm / 105 Ft-Lbs flywheel crank bolts need to be really tight. the flywheel spins at high speeds. likely more than a car wheel. mfg probably recommended applying sealant as well. you really dont want those to come off.

[@AlexHibbertOriginals]

Go and have a check of the torque charts for bolt sizes. Your lugs are M14 and can handle 160Nm (8.8). M10 (on our Bukh) can't even manage 100Nm for 12.9 grade steel.

[@ysesq]

@@AlexHibbertOriginals generally flywheel bolts are one time use only and special bolts but honestly idk much about your particular diesel engine. you may be right or wrong. generally the mfg dont mess up torque specs for critical stuff like that but YMMV.

[@benderbender1233]

✌😎✌

[@UKvet246]

Absolutely no need to remove that cover to replace the oil seal

[@AlexHibbertOriginals]

We hadn't 100% confirmed the leak was from the seal, wanted to properly clean the end of the crank shaft of roughness/residue, inspect the old gasket in case that was at fault, and have a general check inside since the cover has not been off in 16 years/since birth. I agree you can hoik out the seal if you're sure that's all you want to do.

[@JonMadsen70]

:)

[@daylen577]

You should know that sucking the oil out through the dip stick (or really any entry point that's high up) will leave a significant amount of oil still in the engine. Not always an issue, but sometimes it is, and it's good to be aware of that

[@JayMaverick]

Citation needed. The height of the entry point has no relevance here.

[@daylen577]

@@JayMaverick Look at any random flood salvage (after which they have to get all the water out), step one is usually to try this and it never gets everything out. Just too much stuff in the way I guess

[@antimattercarp2720]

@@daylen577 Is it any less than you get from other methods? Generally with extraction I can pull the plug and nothing comes out.

[@teeanahera8949]

Ford sucks the oil from the dip stick tube for their 5 cylinder 3.2 L turbo diesels (at service) as the oil pump is not self priming, the left over oil will keep the pump primed and it’s not such a great volume to be detrimental to the engine. Take note Mazda BT50 and Ranger PX owners.