Pump it up

 

While the amount of work still required on both the locomotive and the main engine shell should not be underestimated, much of what we need to do on both aspects of the project is graft. The fuel pump and governor assembly is the last big challenge as it is a complex box of tricks and while we have made good progress with the box (casting complete, as blog entry 19 January 2023), there are a lot of components to go inside it; 90 according to the McLaren spares catalogue (see blog entry for 10 February 2020).

The governor/ fuel pump assembly is highlighted in red, with the fuel pumps themselves being the four small cylinders, mounted on top of the box, with the pipes running off to the cylinder heads.

The casting for the body is currently with John Dunn Engineering for machining.

The blog entry for 16 February 2023 described the progress made in producing new injectors. To function the injectors need fuel pumps. Unlike the injectors we have not been able to source any drawings and there has been a lot of patient backroom work going on to clone these high spec, close tolerance units from the samples borrowed from the MDB2 engine.

The role of the pumps is to deliver a measured amount of fuel to the injectors, at a pressure which is sufficiently high to be injected into the cylinder at the top of its compression stroke. In the case of the MBD4, the fuel is injected at 1,000 psi.

The work carried out by Grange Square Engineering on the injectors was impressive, in terms of price, quality and timescale and we had no hesitation in asking them to quote for the fuel pumps too. As you will have probably gathered from previous reports, finding suppliers who are interested in manufacturing small batches of intricate components can be challenging. The relief in placing an order with a Company, knowing that they will do what you want in a realistic timescale was enormous.

The extract below is from a spares catalogue for MDB2 engines. The columns are ‘Part Number’, ‘6’ is the illustration number (the relevant part of which is reproduced) with the final column being the number off required (for a two-cylinder engine).

Only eight bits, but they do need to be right, exactly right if there are to do the job. The original pump bodies (part No 595) were forgings. While we are particular about how things are made, four forgings is never going to happen and Grange Square have CNC machined these from solid. It looks like there must have been a lot of swarf produced relative to the component size.

Machining the body for one of the fuel pumps (McLaren spares number 595) (image courtesy of Grange Square Engineering)

Replica fuel pump (left) with original fuel pump (right) borrowed from the MDB2 engine.

Another challenging component is the rack which lifts the cam followers which drive the pumps. The arrangement of this rack is different in concept of the MDB2 engine which is our primary source of reference to the one fitted to the MDB4 engine in the Armley Mills winch. We’ve taken our lead from the MDB4 engine. Grange Square has manufactured the new rack from the solid rather than the original forging. It may be politically incorrect to say ‘can you see what it is yet?' But you may need to look at the final illustration to understand the machining process shown in the three photos below.

The end of the rack appearing out the block (Grange Square Engineering)

Radiusing the arm corners (Grange Square Engineering)

A lot of swarf later and things are shaping up (Grange Square Engineering)

The finished product. 

So, nine bits done, 81 bits to go!

MDB4 Progress

 

You have to do a lot of scrolling back to find the last progress report on the McLaren-Benz MDB4 engine, 3 September 2021. This described the decision to dispatch the engine to a specialist restorer of vintage IC engines, Formhalls, to have the bearings re-metalled & the cylinder liners fitted. They are based a Salisbury, which is close to Stonehenge and consequently time moves at a different speed in Wiltshire. Their six weeks of Wiltshire time is two & half years of Gwynedd time. Ironically, when they heard we had had a crankshaft made by Farndons, they had the gall to mock their lack of communication & delivery skills. Mr Pot, meet Mrs Kettle!

Enough bitching, on the 13th March the engine arrived back at Boston Lodge, new crankcase bearings, whitemettalled & bore, big ends re-metalled, and cylinder liners fitted. Credit where it is due, there also find all sorts of little cracks radiating from the cylinder head studs & these have been laser welded up.

Line boring the crankshaft (image courtesy of Farndon Engineering)

The completed crankcase and bearings (image courtesy of Farndon Engineering)

A very sexy row of crankshafts (image courtesy of Farndon Engineering)

Laser welded repairs to cylinder head (image courtesy of Farndon Engineering)

Cylindrical grinding of cylinder liners prior to fitting (image courtesy of Farndon Engineering)

Cylinder liners ready to fit (image courtesy of Farndon Engineering)

Fortunately the return of the engine coincided with a period of leave for Rick, who duly got carried away. Job number one was to remove the plugs giving access to the oil ways. How the lubrication system works was described in the blog entry for 5 March 2018.

The illustration above is diagrammatic; the ‘pipes’ which lead to the crank shaft bearings are, in practice formed of a series of interconnected oilways drilled into the crank case and engine block. There is an oil way from one end of the block to the other, with individual branches leading to each crank shaft bearing location. At the end of each run there is a plug. When you remove the plugs and poke a small bottle brush in this is what you get out:

The cylinder heads had been overhauled earlier in the project (blog 10 April 2021) and in a moment of wild excitement one was trial fitted onto the cylinder block, with one of the MDB2 rocker covers. The rocker cover castings are still in Chris Barrys’ workshop. Wife, Kids, Dog, 7.5” rebuilds, pah! Come on Rimmer pull your finger out.

A frenzy of painting has ensured, so the cylinder block now looks like this, complete with replica McLaren-Benz plate.

It is not just the block that has been painted, the cylinder heads look lovely too

As do the myriad of cover plates etc. Even the MDB2 rocker covers have had a look-in

Next on the agenda is gasket manufacture. One down,

Some way still to go!

A Trip Across the Cob

 It would be churlish not to note 4415's trips from Boston Lodge across the Cob as part of the WHR100 celebrations on the 24th & 25th June as progress. 

All of Rob Collins’ lovely paint job will be getting grit blasted off in the next twelve months if we stick to the current plan to rivet up the body next winter, so here are a few views at least to capture some of the many completed components enjoying a trip out rather than languishing in the finished parts store. 

Seen below, meeting up with former Dinas shed mate ‘Russell’ at Boston Lodge at 08:54 on Saturday morning.

Optimistically coupled to a rake of 1920s style coaches below, it looks the part, and is the only decent photo I have showing the radiator & the replica ‘MACLAREN’ plate (cast using an original plate from the road roller).

In the end it ‘double headed’ with Welsh Pony, being somewhat lacking in the engine department.

In addition to allegedly inspiring the streamlining on the A4s, the iconic look of KS4415 may have inspired the architect of Snowdon Wharf.

Eventually the sun came out, just as the loco returned to Boston Lodge on Saturday evening and a posed for a few minutes by the cliff.

Sunday saw 4415 going off shed with the full line up of surviving of Ffestiniog Railway early IC motive power.

The head turning impact of early IC motive power can be fully appreciated when you see the platform in this view of the 1917 build, 40HP petrol powered Motor Rail Tractor and the 1927 build 60HP Diesel 4415. It’s a niche market.

Some of the ‘facts’ in this blog may be made up.

Engine Fitted To 4415!

Come on down and see for yourselves!  All of this frantic work on the body is of course to enable KS4415 to make a public appearance in Porthmadog during the Welsh Highland Railway 100 event on the 23rd-25th June. Who would have thought that the engine would be fitted before the event? Martin Greenland, Blackburne donkey engine restorer par excellence, that’s who.

A number of the completed components are going on to give a taste of the engineering as well as the appearance of the locomotive. No surprise that the MDB4 is still at Farndon Engineering. The above view shows the cab interior, partially fitted out with the petrol starting engine, starting gear box and radiator. There is a similar view in 15/- Change (which we can flog you out of the back of the cab if you have not already got one).

Now you can play ‘spot the difference’ and complain about the recess on the flywheel and the missing Diesel engine, the front hatch cover is removed in the old view,  no cab handrails in the new…

Ha! Cab handrails now planished (drawing 33362 refers). The one on the right is the replica, turned up by Rob Bishop and all of them have  been planished to within an inch of its life by Rob Collins. They are upside down in the photograph.

This view shows the handrails fitted, together with the cab back and driver seat (both original components).

We have had to let some new steel into the cab back, the majority (coloured red oxide) is original. The angle iron stay stiffens up the back sheet to ensure that overweight drivers do not buckle the sheet, another largely original component with a repair to the top. All of the other angle components are new.

To give the front elevation a bit more character the hatch handles have been recovered from the old hatch and fitted to the replacement.

So, looking more complete than it has done in many a year, 23rd-25th June will see this marvellous Diesel pioneer out and about. Come on over, see the beast, buy the merch!

Making a spectacle

Like a moth to a flame I’m drawn to the awful and predictable pun, even though the Kerr Stuart drawing refers to them as a windows. Going back in time to the 17 October 21 blog, the mechanics of the window catches were described when Bob Smith and Adam Livingston were busy making the patterns, the castings from which arrived back in time to make an appearance in the 16 February 22 entry. Norman Bond has subsequently produced the patterns for both the round and rectangular windows and the components for these have been cast too, arriving during the special Christmas of 2022 with the injectors, governor body and a box of new drills to make all those rivet holes.

Our machinist man for these little jobs, Dave Linton (who is also our little man for machining jobs) has put some considerable mental effort into working out how best to set up the various bits for machining. This is the clamp set-up used in the four jaw chuck of the lathe to turn the catches and hinges.

The hinge castings and bearings are seen here post machining. The castings with the slots are the lower hinges to the windows.

The slots allow the hinge to clamp onto the pins, to hold the window in the open position.  The full assembly is shown here, with the wing nuts also machined by Dave.

Who also made all of the other brass components required to fit the hinges to the cab sides. 

Like all blokes who have kept something in their shed for years, he was particularly pleased that the kitchen worktop offcut from 1999 made a wonderful mounting plate to support the round windows for machining.  It is seen here mounted on a rotary table, being used to machine  two castings to make them into a matching pair. 

The drilling in the lower picture came first but it is hard to envisage the ingenious rotary table set-up from the drilling view. Worth capturing the moment in case you want to try this at home.

With all four castings drilled and mounted on the board Dave then put the whole set in in one of the Dean Smith & Grace lathes at Boston Lodge to skim them.

The various components, with the exception of the catches to hold the windows shut, are seen here in a dry-run assembly on the loco. It is curious that the bosses are outside the cab, requiring a slot cutting in the cab front.

Mounting the windows in this way moves the centre of the hinge pins outwards, allowing the hinges to be almost flush with the cab sheet (as shown in the drawing below). 

Another minor detail that is so nice to get right, which can be seen in the photo below:

Body Talk

 

Much of the progress over the last five months has been boring. Literally. Probably used the joke before but I don’t care as the task of drilling the holes to allow the body to be assembled is nearing an end. Forming the lovely, new rectangular components was something that Boston Lodge is well set up for, as it has a large guillotine. Many of the sheet steel components are connected by rolled steel angles and while we have been able to recover one (as described in the 14th January 2023 blog entry) the others are too far wasted for re-use. Several of these angles are rolled to some quite tight radii, and require some skill to form them. In addition the main body wrapper, with its distinct ‘air-smoothed’ appearance is too corroded for re-use.

With the arrival of the wrapper, from Richards Sheet Metal the body started to move from being a series of one-dimensional components into something more tangible.









The recovered angle which connects the wrapper to the right hand side panel was soon trial fitted to find that the radii are beautiful match.









The other angle was too heavily corroded for re-use and a replacement has been manufactured by Chris Brady, a blacksmith from Tudweiliog.








Chris has also formed up a new angle hoop to connect the body to the cab, the very rusty remains of which were illustrated in the 14th January 2023 entry.




The body hatches (both top and front) are formed of two angle rings, one attached to the body, the other to the hatch which sit on top of each other. Chris has made these too and four more lovely pieces of angle iron you have never seen in your life.






The photo below shows the new, rear angle hoop and upper wrapper meeting the old side panel and angle. There is a rivet that attaches the angle to the side panel that needs to go in before the hoop is fitted.

After mucho drilling, the body is now a thing. The cut outs for the hatches have been partially laser cut, but left in situ to ensure that the body has some rigidity before the angle rings (which will add a lot of strength) are fitted.








The covers for the hatches have been ordered as laser cut parts. Here is Ben Boulter drilling even more holes to fasten the covers to the angle rings. The original front cover can also be seen in the photo, being used as a point of reference.





One of the cab side panels had some corrosion at the bottom. Chris ‘Rimmer’ Barry is seen here with the guillotine, about to remove a strip which has subsequently been replaced with new material.





A very tidy, massive rectangular hole had been cut into the other cab side at some stage in the past, so that has been replaced. The photo below shows the all new, right hand cab side, which is again full height for the first time since 1929.







Both cab and bonnet are rather large items to store in a workshop, so they have been temporarily mounted on the chassis. While we are quite pleased with the amount of original body that has been recovered (painted red oxide in the photo below) the amount of new steel added is all to apparent. In this view of the left hand side the new strip of steel grafted in to the lower can side can be noted.







The yellow blob on the cab side is a quick 'works plate'. There are two sets of holes, the outer holes are for the longer, elliptical Kerr, Stuart plates and the inner ones for the Hunslet/ Robert Hudson plates fitted in 1934.







Don’t buy a second hand car from Hunslets! In 1934 they were passing off second hand goods as new!







Dewi Atherton has machined up the replacement sliders for the shutters







This is the one good shutter slider that is fit for re-use attached to the replacement right hand side cab sheet







On the left hand side, the lower cab sheet is original but both shutter sliders are new. Seen here with a trial fitting of the teak shutters Clive Bickley produced in 2019 (see 11 December 2019 blog).







Rob Collins is seen here sanding back filler applied to tidy up some of the worst of the pitting to one of the old body panels.







With the front hatch temporarily fitted and a coat of primer Kerr, Stuart 4415 is quite an impressive beast.