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40+ tonnes of Boatshite - engineshite update 9/5/20


coalnotdole

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A real sparks would have done that cable tray in one piece and wouldn't cut across the holes like that ;).

Flip your vertical run so the cut end is at the top and make sure it's all earthed.

You can can get premade links (that bolt on to the tray) or get s short piece of earth cable and crimp some lugs to each end.

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Rudder guard - currently dry fitted after getting fed up of it being sat in the yard getting in the way! needs to come off again and be bedded on with sealant but for the moment is useful for standing on whilst drilling through the transom for knees and cross beams etc.

 

 

Hung in place:

 

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The holes in the flanges are M20 and I wanted to coach screw it on, M20 stainless coach screws were going to be several hundred quid so I have made some top hat spacers:

 

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These were then drilled to suit M12 coach screws after this photo was taken:

 

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Fitted in place:

 

275.jpg

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A real sparks would have done that cable tray in one piece and wouldn't cut across the holes like that ;).

Flip your vertical run so the cut end is at the top and make sure it's all earthed.

You can can get premade links (that bolt on to the tray) or get s short piece of earth cable and crimp some lugs to each end.

You'll be pleased to know these photos actually show the tray at a mock-up stage before fastening it in place.

It was shortened so the cut lines missed the holes and the ends radiused and deburred.

As its 316 stainless tray the fittings are bloody expensive and as the rest of the original tray work all just jumps from tray to tray I figured I could live with it!

 

There is also a sideways offset at the other end of the horizontal tray which isn't shown in these photos and which would have been almost impossible to do in the space available, theres only about ten cables going to be on it so i think i can make a neat job of the clipping.

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Engine related tangents..

 

This is the pipe that carries excess fuel from the scavenge pump on the injection pump back up to the pressure relief valve on top of the secondary filters, it then takes fuel from both these sources and deposits it in the fuel return manifold at the back of the block from there it goes back to the tanks:

 

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When I bought the boat the banjo fitting on top of the filters had been damaged by over-tightening and as its under constant pressure whilst running it would leak fuel. and when the engine was stopped would introduce air into the fuel filters..

So drawing a blank on getting an identical banjo fitting I sourced a stainless one from a brake pipe manufacturer and dropped it off with a local engineer to tig weld to the steel pipes, Sadly they ended up making a mess of it with bits of copper pipe sleeved over and silver soldered and it leaked as badly as ever:

 

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Now eight or ten years later the internet has really moved on a bit and I managed to source the correct size and type of banjo fitting:

 

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Silver soldered to some kunifer pipe:

 

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And fitted in place:

 

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Another problem with the fuel system is the bolts that hold the bowls onto the body of the fuel filter. My original filter had been overtightened and leaked so I sourced a new old stock filter assembly from malta at great expense.

This also leaked! so I bought another from cyprus this time but it wasn't much better.

 

Its a die cast zinc alloy body with slightly counterbored areas around the bolt holes which have a copper and asbestos composite washer that sits in them, apart from it docent really sit so to make it seal you have to overtighten the whole thing..

 

 

Bolt and hole:

 

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Copper asbestos washer - you can see where its been crushed off center:

 

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A modern CAV type filter head showing the use of an O Ring on the same type of assembly:

 

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Which sits into a tapered counterbore in the body:

 

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Into the milling machine with one of my filter bodys:

 

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I then machined a tapered counterbore in the body and fitted washers and O Rings to the bolts:

 

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It seems to be a success but I haven't really tested it as I ended up taking the primary fuel filter apart next...

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The large bulkhead mounted primary fuel filter has never been changed in my ownership as I had a realistic idea of parts availability for it - IE: Nill.

 

 

 

Bowl and both elements disassembled:

 

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Sludgy:

 

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So I splashed the cash and bought a Racor filter which was the closest thing I could get size wise to the old one.

 

The pipe connections however were quite different so rather than mucking around with adapters I ordered some flare unions and machined them down to suit.

 

 

Modified union on the left:

 

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Fitted to filter:

 

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And in situ on the bulkhead:

 

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The gearbox oil cooler has also had a small water leak since I bought the boat which I had been ignoring as it looked like the aluminium body would probably be corroded beyond repair once disassembled.

I was doing some sub-contract work a while back for an engineering firm who just happened to have a new old stock body housing sat gathering dust in the storeroom so I did a deal.

 

 

Old Body after disassembly (it actually wasn't very badly corroded at all and has since been flogged to someone as a replacement for there cracked housing) :

 

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Mounting plate:

 

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New body and end caps in background:

 

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Bracket shot blasted and cooler core acid dipped and reassembled into new body using new seals:

 

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Likewise the raw water circulating pump has been something I've been studiously ignoring since I bought the boat - I stripped the pump off the engine from the spares boat but it turned out to be a completely differant size to mine.

 

 

Heres a nice diagram showing the cooling system (mine is slightly different in that the gearbox cooler is raw water cooled):

 

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And heres the impeller once I took the pump apart:

 

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And the main seal:

 

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Acid dipped and awaiting reassembly:

 

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There is a cam plate which in effect squashes the rubber impeller vanes and forces the water out of the pump - the thicker the cam plate the more water is forced out, My pump is a "low flow" pump and the first three cam plates I ordered were too thick or two large (and cost £38 each non refundable) This model of pump is no longer made so getting parts other than the common wear items is a bit of a pain. Finally I managed through trial and error to get the right part.

 

 

Thin and thick cam plates:

 

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Reassembled with new cover plate and screws, cam plate, wear plate, seals, bearings and impeller as well as stainless studs on the pipe flanges:

 

301.jpg

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Having come this far it seemed logical to give the cooling system a complete overhaul.

 

Although the engine has done minimal hours since it was last overhauled by Rolls Royce in crewe (who bought up the rights to the FD6 when Fodens went bust)Its a bit of an unknown as to how well the previous owner cared for it - when I bought the boat it came with a 20l barrel of engine oil, which was advertised on the label as "a premium blend of recycled base oils"

 

Other than topping up the anti freeze occasionally I have always put off servicing and oil change (as I only have a limited number of oil filter cartridges and they are over £100 each if you can find a supplier! )

 

 

Main heat exchanger disassembled:

 

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Seals for this heat exchanger are no longer available so some time was spent coming up with alternatives:

 

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Ready to refit:

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Oil filter bowl removed allowing access to engine oil cooler:

 

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Oil cooler removed:

 

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Showing the state of one of the coolant pipes on the oil cooler - To replace this involves removing the cooler and breaking several gasket joints onto the engine block. Better to do it all now than have to take it all apart again in a few years when it fails:

 

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Oil cooler core - water flows through the middle:

 

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Worrying amounts of hair stuck in the fins:

 

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A quick check of the manual shows the cooler is pre oil-filter:

 

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O Rings from cooler which had swollen so much I really struggled to get it apart:

 

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Main components of Oil filter and cooler:

 

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New UNF stainless fixings for oil filter bowl:

 

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New old stock gasket for oil filter gives some idea of scale - the filter is huge. (note TBA logo, Turner Brothers Asbestos of Rochdale - the sign of a quality asbestos product) :

 

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When I came to drain the sump and gearbox oil it became apparent that neither of the drain pumps were particularly effective. I stripped them down and one had a broken leather cup washer and the other had been replaced for an incorrectly sized rubberised cotton cup washer.

Part of the assembly had also been cross threaded and stripped then stuck together with loctite.

 

Leather washers of the correct size aren't available off the shelf and rather than getting them made especially I thought I'd see if I could modify them to take modern nitrile cup seals intended for hydraulic rams.

 

 

Damaged leather plunger washer:

 

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Comparison:

 

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I had to turn some brass rings to fit inside the new seals:

 

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Fitted:

 

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Next up I thought I had better check the thermostat - There was a stat in a cupboard when I bought the boat which I assumed was a spare, When I finally got the housing apart (which had seized onto the steel studs as someone had neglected to refit the copper washers which stop coolant getting forced down the threads of the bolts) it turned out there was no thermostat fitted.

 

I'm pretty certain this is a previous owners bodge as part of trying to fault find a stalling/overheating issue which eventually turned out to be water backing up in a large water cooled wet exhaust silencer and eventually causing enough back pressure to stall the engine. The silencer had been fitted by the navy just before decommissioning as they had been towing ammunition barges and decided the two stroke diesel with dry exhaust out the funnel wasn't a great idea near explosives!

 

I removed the water cooled exhaust when I bought the boat and have had no problems since.

 

 

Water rail/thermostat housing and header tank:

 

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Correct gaskets vs lump of glossy cardboard:

 

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Refacing where I had damaged the gasket face splitting it off the seized studs:

 

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Testing the three port thermostat:

 

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Another area of concern has always been the water jacketed exhaust manifold - Its always seemed to weep blue antifreeze crystals so I was worried it had become porus.

I have another which came from the engine out of the spares boat so figured I'd strip them both and see which was best

 

 

Manifold - the heat exchanger fits to the brackets:

 

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Theres about 80 studs that hold the water jacket cover plates on and every one was a nightmare to get out:

 

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Carbon build up in the exhaust ports:

 

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Stripped down manifold:

 

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The cause of the crystals seems to have been failing gaskets allowing water to creep up the studs and get beneath the paintwork.

 

I ordered new stainless studs for the manifold (from a company in the midlands which turned out to have made the originals in 1966! )

However £60 tooling setup costs per run of studs meant it was only economical to get them to make the most common one of the 3 different size studs used on the cover plates.

 

For the other two sizes I bought off the shelf imperial studs and shortened them in the lathe to suit then turned the correct unthreaded pip on the top and extended the threads as necessary.

 

I also repeated this process to make studs to replace the header tank lid and thermostat housing fastenings.

 

 

Standard stud, Shortened stud with pip turned, original stud:

 

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Finished copy:

 

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New studs fitted:

 

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When refitting my newly overhauled oil drain pumps I noticed the mounting bracket for the gearbox pump was loose.

For some reason known only by Self Changing Gears Ltd of Coventry they chose to use BSF fastenings to hold the rear housing onto the aluminium body of the gearbox. These had then been overtightened by some navy fitter when installing the sump pump and had pulled the threads out of the box.

 

access wasn't great but I set about helicoiling the two failed fastenings, as they're quite deep this was a bit of a pain and as neither of the holes was blind it made trying to remove the tang without losing it into the gearbox somewhat challenging!

 

 

 

 

Gearbox and pump with the two missing bolts just about visible:

 

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BSF in aluminium! :

 

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Helicoil installed:

 

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Specially modified pliers:

 

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Success:

 

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For something made in the late 60's I really can't believe that BSF was the thread of choice, Mind you I think self changing gears had become part of the british leyland empire by that stage so maybe it does make sense in a strange sort of way!

 

 

Thanks for reading

 

Dave

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Has it sucked something through that impellor previously or was that just long term wear tear and a bit of cavitation?

The cam plate was badly worn which has a tendency to tear chunks out of the vanes. Also the previous owner kept the boat moored on a gravel bank in bembridge harbour so I imagine it sucked a fair bit of grit through while he owned it. Interestingly I didn't find any of the missing bits in the rest of the cooling system - usually they end up lodged in the pipes of the heat exchanger further down the system.

 

The impellers are considered a wear item and would usually be replaced every season (although ones this large cost about sixty quid)

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Those fuel filters are gash, a spin-on is far less of a pain in the arse; it might be an idea to try and do the same with the oil filter if spares are becoming unavailable, but given how heavy the housing looks the pressure rating might be beyond the capabilities of a spin-on and more in the realm of a hydraulic filter unit.

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The slightly newer CAV/Delphi equivalent of those filters is still the mainstay of primary fuel filtration on the vast majority of yachts and boats which I work on so I'm pretty used to dealing with the limited amount of faffing to change them. I also dislike the fact most spin on filters don't have a water drain in the bottom of them - and those that do tend to be quite expensive to replace.

 

I have another five oil filters in stock I think. As you say it would be easier enough to change to a different filter housing in the future if needs be as the piping is all external. That said there seems to be enough call for FD6 parts still that theres a couple of companies who are willing to commission manufacture of batches of service items even if the prices are quite high

 

As the filter is pre pressure-relief valve I believe it has a very high working pressure, I have heard anecdotal evidence from a railway engineer who fitted a parker hydraulic filter housing as a replacement on a fd6 engined shunter which promptly split and dumped the oil as it couldn't cope with the pressure involved.

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With all the exhaust-side ancillaries stripped off the engine currently looks like this:

 

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I'm now thinking it probably makes sense to pull the heads and do a full top end overhaul - There is quite a bit of carbon in the exhaust ports and theres also signs of carbon around the tops of some of the valve stems which must have come up the valve guides (in fact the FD6 has no separate valve guides, rather they are machined directly into the heads)

I think that this excessive carbon is probably caused from the time the engine was operated with the water cooled exhaust and the excessive back pressure it caused.

 

In preparation for pulling the heads I have bought another set of head gaskets (to replace my current stock of spares) as well as a full set of the various O Rings needed to seal the wet liners if for some reason I should end up having to remove one or more (which is NOT part of the plan! )

 

Also as parts are to all intents and purposes No Longer Available I figure it makes sense to collect them now rather than in ten years time when they're even rarer or more expensive.

Some of the gaskets and seals I've bought are the last known stock in this country.

 

Some parts such as the obsolete foden ring seals between the water manifolds which run along the top of the heads, which I paid a decent sum of money for an incomplete set of, actually turned out to be nothing more than imperial dowty washers spray painted and packaged in rolls royce bags. So future availability shouldn't be an issue - Other items such as the thermostat will probably require a bit of engineering to come up with an alternative solution when replacement is needed.

 

This post will show some of the parts I've spent several thousand on acquiring in order to overhaul my engine or as "just in case" spares.

 

 

 

Headgaskets and liner seals:

 

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Years ago now I picked up a set of six brand new crated heads including rocker gear:

 

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Note single cam follower and twin exhaust valves:

 

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A couple of months ago I struck a deal for some more new old stock parts: Heads (this time without cam followers) also a brand new supercharger and fuel injection pump.

Hopefully neither of the latter will ever be needed but as the roots type supercharger is unique to this engine and supposedly needs a special phasing machine to setup if disassembled which only the original manufacturer could do, it seemed sensible to have a spare.

 

Likewise my injection pump has an overhaul labour price of £1200 + parts. And a lot of the parts are very hard to source these days.

This spare pump is intended for a manual governor application (mines hydraulic) but the injection elements, body casing, delivery valves etc are all identical to mine so would provide all the parts for a full rebuild if ever required - probably just a case of swapping my existing control rack and governor sandwich plate onto this one and getting it set up.

 

 

 

 

Crate of goodies:

 

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Heads, Bringing my total spares to 15:

 

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Blower/supercharger and Injection pump:

 

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The injectors actually pass through the waterway in the head with a copper alloy sleeve to make the seal, the bottom of the sleeve acts as the injector sealing washer and a special stepped reamer is needed for refacing this before refitting the injector:

 

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And lastly this is the top for the air intake oil bath cleaner fitted to the bulkhead on my engine, mine has rusted out and is pretty much beyond repair and I had been planning to get a metal spinner to make up a replacement at huge cost.

 

A company specialising in consignment sales of obscure engine parts sourced me this one - Apparently the source has another 49 of them in a crate in his barn in staffordshire although they were supposed to have been scrapped in a clearout a year ago. luckily for me they had been overlooked!

 

 

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Many of these items such as the heads are still in there MOD packaging with dates from the mid 60's, its testament to how well these were wrapped and preserved that they were disposed of during the 70's, ended up in barns, sheds and underground ammunition repositorys and are still in mint condition over 40 years later!

 

I have been offered a complete FD7, Crated and un-run since MOD rebuild, This is the Turbocharged and intercooled version of my engine but they had a poor reputation for longevity. for the moment I have resisted...

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Years ago you used to be able to get an auxillary centrifuge oil filter for heavy plant/ HGVs and similar. If you used one of those as a pre filter those remaining filters could last a good long time. Having cleaned out that type of filter they are very effective.

We have one on the side of our main engine, it's a Mann & Hummel; they are available in a range of sizes although the cost is likely prohibitive given how many hours the engine is likely to do in a year. A quick google suggests there are used alternatives from scrappers, I found a DAF unit listed on ebay and a multitude of Landrover TD5 units.

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The flue pipes for my stove haven't faired very well in the 8 years or so since I made them.

 

A combination of mild steel and soot along with condensation forming in the final vertical section running up inside the funnel causes a lot of rust which then collects in the bend beneath the funnel and chokes the pipe.

 

Also as all the pipes are solid with flanged joints its quite a pain to remove and clean - you end up having to unbolt the flanges then beat the removable section out with a lump hammer. When I made it the removable section would just drop out but several years of heat and rust have meant things have moved a bit.

 

So I've made a start on replacing it with stainless, there will also be a T piece at the bottom of the funnel to act as a rodding eye for cleaning.

The removable section will be made from flexible polylok type pipe with V band clamps like you get on turbo output flanges.

 

 

Small fortunes worth of 10mm stainless plate for the flanges:

 

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Not having the patience to do a cad drawing and send the plate off for laser cutting, I got a local fabrication firm to hack the flanges out oversize with there slightly crap plasma cutter:

 

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I then tediously turned the excess 8mm off on the lathe, a horrible job as the slag and hardened cut kept destroying cutting inserts:

 

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And trued up the square flanges in the mill:

 

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Schedule 10s pipe fittings:

 

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Stainless flexi pipe:

 

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As far as its progressed to date:

 

356.jpg

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When I stripped the spares boat the exhaust piping was one of the things I kept.

Back when I replaced the missing funnel and did away with the water cooled exhaust I made an exhaust up from 4.5" piping robbed from the local unigate creamery demolition site.

 

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However it never sounded quite right - at certain rev's the harmonics in the wheelhouse would make you want to jump overboard!.

 

I think partly I'm to blame for assuming that "bigger must be better" and not having kept the 3.5" bore which it starts off as.

Also for convenience I used 90degree weld bends - The original type instead has a large radius bend incorporating a flexible section:

 

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However the rest of the piping from the spares boat which connects between that bend section and the bottom of the funnel was in poor condition and also the wrong length and angle for my later design of funnel.

 

 

 

Measuring flanges:

 

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This time I've got someone to cut the flanges with a CNC plasma which seemed pricy but taking my time and lathe consumables into account is probably a lot cheaper than the previous flanges I made, They just need a small tickle with a flap disc and are ready for use.

The small things on the left are the lugs for my window bars which I got him to cut out of some 5mm stainless at the same time:

 

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As I only need 90cm of pipe I couldn't justify spending £400 on a whole length of schedule 10s and instead opted to cut and shut some of the larger diameter I'd already bought for the stove flue:

 

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Its surprisingly hard the cut 1.5" out of the length of a pipe and close it up without it becoming too oval! I have since welded it up but don't have a photo of it.

Welding the flanges on will have to wait until the exhaust manifold is refitted to the engine.

 

 

 

This is the one and only sample I had of the torsion springs which are supposed to counteract the weight of the cabin hatches as when opening them from inside they are initially quite heavy if your female/not a weight lifter!:

 

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Basic drawing which I sent along with the sample to a spring manufacturer in Nottinghamshire, I had intended to order 7 pairs to give me some spares (they're fitted in handed sets) but due to cost constraints ended up ordering only 5 of each:

 

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A month or so later a nice parcel arrived, I've had them made in spring stainless which should hopefully increase there life a bit:

 

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First pair fitted:

 

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I'm quite pleased with how they've worked out, and despite the fact the reason they were ordered was no longer relevant by the time they were actually manufactured it has at least meant I can get on and do the final fit of the new hatches which have been sat around for several years!

 

Dave

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Abrupt changes in diameter, up or down in size, is always going to produce unpredictable effects on exhaust noise and efficiency, the potential for setting up weird harmonics is significant; IIRC correctly from fluid dynamics lectures 20 years ago the optimum is a trumpet shape, although a shallow taper is a reasonable compromise for ease of manufacture.

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This is a 2 stroke diesel isn't it? Excuse my thickness but does exhaust design have has much effect on engine performance as on a petrol 2 stroke?

Probably not, given the supercharger is mostly responsible for the breathing of the engine rather than precisely designed resonator chambers in the exhaust system.

 

In theory...quite prepared to be proven wrong though.

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