The next stage in the refurbishment and sorting of the valve timing issues is to pay some attention to the HP Valve problems.
A last quick post for the day, then it’s back to the cold workshop….
The pump drive on Befur has been an on-going source of angst and failure… So we redesigned and rebuilt it!
This appears to be much better, and pending final cleaning, plating etc. here is a video of it in action on the bench!
As my first job was working as an Instrument Technician for Shell Research in the Applied Physics department, I became interested in the measurement of physical systems… thus I was interested in Engine Indicators as a tool for evaluating engine performance, and measuring valve events and gas-flow in steam and very large marine diesels.
Given my later life in computing I concluded that a digital version of one of these instruments could be made to evaluate the performance of Befur’s engine.
I penned an article for The SBA’s Funnel magazine, but the publication of this has been delayed, so I am publishing it here for those interested.
It’s still a prototype, and in need of further development, but it has provided some interesting data – which at least prompted further analysis and investigations into what happens inside Befur’e engine…
I have attached to this post a PDF describing the Digital Engine Indicator, which you can read and download here
Well, we have been working on the list we made in the last post, and have some positive news, and some better understanding of the problems…
I spent a couple of days with the engine on the bench and a dial indicator attempting to find and measure the wear or absence of same…. We have a page or two of measurements…
From Experience two other issues to consider
While these are not drawing errors, they have emerged over the first 3 seasons with the engine, and should be considered by builders.
HP Valve Chest to Cylinder Joint
In the BOOK the designer suggests using Araldite? as a jointing/sealing material… its not a solution, particularly for this joint.
The joint between the HP Valve Chest and the HP cylinder is problematic, as the sealing faces are very thin, and the two components are only secured by 4 bolts, which are hard to tighten and not well positioned to ensure a steam tight joint.
My first attempt was using “SteamSeal” jointing compound – this failed quite quickly.
The second attempt was using “Heldite” jointing compound – this failed within a few hours.
My last attempt was using “Oakenstrong” gasket paper, I had resisted this, not wanting to affect the overall block dimensions. However, rebuilding with gasket paper and jointing compound (Heldite) does seem to have cured this problem.
Lubrication of “small ends”
I spent a long time chasing a knock that appeared to come from the LP small end. Rebushing the piston rod and a new pin did not cure this, and it was clear that the pin was suffering.
This was finally cured by increasing the size of the Lubtech pump units feeding these bearings and slide ways. A “black” one (0.1cc/stroke) silenced the knock instantly.
I am sure that a better builder than me might make the sideway fits better, but the lubrication points at the bottom of the piston rods have to lubricate the “small end” and the slide-ways, and so need a heavy oil flow to ensure that both bearings are supplied on each cylinder, as I think the oil preferentially flows to the slide-ways, starving the bush at the lower end of the piston rod.
Timeframe missed a bit
Well, looking back the first post here was on 8th June 2011, and we aimed to finish and launch by 26th June 2015 – planning was never my hot spot! We did change the goal posts in mid-flight (adding a sail, loo, etc, and stretching her from a planned 16ft to almost 27ft to get everything in, but hey we did get there!), and on the 20th July 2020 we took her for a steam and sail on Windermere with a cameraman (Roger Heise from the SBA) on hand to record her 2nd trip under sail (thank you Roger).
Notes on the Steam Bit
Before I inflict an album of sailing photos on you, a couple of notes on the steam side, especially for Leak Compound builders…. Continue reading
Well winter is with us
A quick note on where we are at, while we wait to hear from Windermere Lake Wardens on our application for a berth at Ferry Nab next year….
The boat is back in Heggerscale, and we are working on the following items:
- LP cylinder “small end” (crosshead bearing) replacement: This had worn, partly due to a severed oil line at some point last year, and partly due to the fact I had to “re-ream” it at erection time to correct some misalignment. So a new bush fitted and reamed to size.
- HP valvechest to HP Cylinder block leak: This is a recurring problem, there just is very little sealing surface round the port pockets. This year’s fix is an Oakenstrong gasket and Steamseal – let’s see if this works!
- Cabin roof: Learnt a lesson here about cheap plywood…A small leak around the antenna cable resulted in the delamination of almost the complete forward part of the cabin roof. So it’s now been cut off, and will be replaced with “genuine” marine ply, and clad in epoxy and cloth like the hull – hopefully with more resilience! As it happens the removal of this rotten wood made the next job much easier.
- Erecting the mast: As you may have read in an earlier post the Mast Partners had been made, so in the last few weeks we installed this on the boat, inserted the mast, and then started to wonder how on-earth we were going to raise the mast to a vertical position. Practical Junk Rig as usual came up with a good solution. This involved using a “bi-pod and running fore-guy” which worked faultlessly, so we saw the mast upright for the first time yesterday! This is almost a single-handed job, which is good, as it will be repeated each time we need to trailer and re-launch her.
The next bit of this process, is to fit the masthead fitting (pictured above), (with navigation lights, VHF antenna and various shackles and blocks. Then we will cast a hard rubber square block at the foot of the mast, to secure it in the tabernacle base – the only problem with this is that the rubber components say they need to be mixed and poured at over 20-degrees C to cure, and it’s currently about -5-degrees C….
- Once all this is done, we will put the boiler thru her annual test, and then reinstall the engine and hopefully enjoy SY Befur in her intended mode as a Sailing Yacht!
- Oh yes, and we also need to turn a pile of sailcloth, blocks, shackles, rope and ally battens into a sail – more on that later!
Well that worked!
It would appear that the work on the burner paid off. Yesterday we had a fine day’s trip on Ullswater, from the marina at Watermillock, all the way to Glenridding without a single problem – virtually the full length of Ullswater. (About 3½ hours steaming). The first time we have managed the full length of the lake!
We took most of it at a leisurely pace, with a couple of bursts of speed to avoid yachts out racing…. Continue reading
Well, a good day! Befur went back on the water yesterday, and it would appear that the work over the winter worked well.