davidwheeler
Permanent resident
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« on: 21 March, 2015, 10:47:03 AM » |
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Old Boot's block is badly corroded, probably worse than most, pic 1. Many years ago I had someone try to weld the face with the result that the top of the bores was eroded and the welder gave up "too contaminated to weld", pic 4. For years I have used ever-improving putties to make repairs but the last time the water got into the combustion chamber was due to a big pit on the outer side of the cast iron land as shown in pic 3 - it just overlaps the edge of the (new head) combustion chamber. I had prepared a "poppet valve" to fit into the hole (plus high temperature putty) when I read in the MGOC mag about cold metal spraying. http://dycomet.co.uk/ I found the nearest operator in Manchester and went down last week with the block. I was shown round a very impressive and well equipped machine shop in which was the metal sprayer - a very modest sized piece of kit. High pressure air is superheated electrically and fed into a thin venturi tube where it entrains very fine metal powder which is then sprayed onto the substrate. Pretty well any metal can be so sprayed and, as I saw, it really sticks. I was handed a piece of sprayed metal and it was hot to the touch but not unbearably so. The plan is to build up the cast iron liners with nickel steel and then the aluminium with aluminium. Watch this space! |
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David Wheeler. Lambdas, Aprilia, Fulvia Sport.(formerly Appia and Thema as well).
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simonandjuliet
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« Reply #1 on: 21 March, 2015, 11:07:52 AM » |
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Will be very interested to see how it all works - any chance of photos showing the process and machinery ?
Bonne Chance !
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AmilcarCGS, ApriliaCabrio,S2Aprilia, 2xArdea c'cino,S4 Ardea, Appia c'cino, Appia f'cino,B20s4,R4 Sinpar, R4 Rodeo, 65 Moke, 3xR60 Tractor, 2xToselli 78, Moto Guzzi Ercole,LR Defender, Mini ALL4 JCW, Moto Guzzi Cardellino, Fulvia GT, RE Himalayan
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fay66
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« Reply #2 on: 22 March, 2015, 01:18:21 PM » |
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Way back in the 1970's at Vauxhall Motors we used to recover crankshafts using sprayed metal. Brian 8227  |
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Own 1966 Fulvia 2C Berlina since 1997, back on road 11-1999.Known as "Fay"
2006 Renault Megane 1 5 Dci Sports Tourer
Dedra Technical Adviser
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DavidLaver
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« Reply #3 on: 22 March, 2015, 02:13:43 PM » |
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The phrase "submerged arc" comes to mind for building up cranks. Anyone know what that is or was?
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David Laver, Lewisham.
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donw
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« Reply #4 on: 22 March, 2015, 07:04:13 PM » |
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David
Hope it goes well, very interested I have a block which could do with the same if successful.
Don
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Don Williamson
Member 111 joined 26th July 1963
1917 Theta 2str
1926 Lambda torpedo
1930 Artena berlina
1933 Belna coupe
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davidwheeler
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Posts: 1487
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« Reply #5 on: 09 April, 2015, 08:49:42 AM » |
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If this works there will, I am sure, be a queue outside the works. Hot metal spraying has been around for many years but is a different process that deposits excessive heat onto the workpiece and would not do for a Lambda block! I remember taking Boot's exhaust manifold into a works in Bristol 40 years ago and getting it aluminium sprayed. Alas, it all burned off in a few years. I shall try to get some photos next time I am down there, I hope to collect a repaired block.
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David Wheeler. Lambdas, Aprilia, Fulvia Sport.(formerly Appia and Thema as well).
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davidwheeler
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« Reply #6 on: 16 June, 2015, 06:31:33 PM » |
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Here is a first update with photos from Dycomet asking if they should proceed. I have said yes!
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David Wheeler. Lambdas, Aprilia, Fulvia Sport.(formerly Appia and Thema as well).
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the.cern
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« Reply #7 on: 17 June, 2015, 06:09:12 AM » |
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David, I have been re-reading this thread with interest. My B20 heads are in a dire state, of particular concern is the corrosion in the combustion chambers where there has been a significant loss of metal. My photographs in 'A B20 Story' show the extent of the damage.
Two questions ...1) do you think that the cold metal spray process would be robust enough to cope with combustion chamber temperatures and loads?
2) How can I find a Dycomet service provider near me (in Essex)?
Good luck with Old Boot's head, I hope the process works well there.
Andy
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the.cern
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« Reply #8 on: 17 June, 2015, 07:57:29 AM » |
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The phrase "submerged arc" comes to mind for building up cranks. Anyone know what that is or was?
David, there is a process called 'arc spraying'. These guys do a short understandable explanation. Maybe this is what your are referring to. Metal Spray Specialists - ep-coatings.co.uk Adwww.ep-coatings.co.uk/ Andy |
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frankxhv773t
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« Reply #9 on: 22 June, 2015, 08:59:11 PM » |
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"The phrase "submerged arc" comes to mind for building up cranks. Anyone know what that is or was?"
Of no great relevance to the overall subject but I have come across a "submerged arc" in an engineering application as "spark erosion" where turbine blades were being precisely machined using an arc submerged in what looked like a sort of oil bath. However this would hinder rather than help the crank in question.
Frank
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davidwheeler
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« Reply #10 on: 26 June, 2015, 02:07:04 PM » |
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Insofar as I am aware, Dycomet in Manchester are the only people doing this in the UK but I have not searched recently. It is an European company to be found at http://dycomet.co.uk/ The process involves passing high pressure air through a gun where it is accelerated to supersonic speed. Metal powder is then introduced into the stream and exits at high speed but, as it is but powder, the heat capacity is very small and the workpiece is only slightly heated. A lot of their work is repairing cracks in cylinder heads so I guess that it would do very well for Aurelia heads. The pieces I have seen appear to have become solid metal integrated with the original. Why not give them a call? I contacted Head Office in Nederland and they referred me to the Nick Gilfillan in Manchester. www.cylinderheads.co.uk info@cylinderheads.co.uk0161 368 6060 |
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David Wheeler. Lambdas, Aprilia, Fulvia Sport.(formerly Appia and Thema as well).
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the.cern
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« Reply #11 on: 26 June, 2015, 04:55:14 PM » |
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Excellent David, thank you very much for that contact.
Andy
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davidwheeler
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Posts: 1487
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« Reply #12 on: 04 August, 2015, 08:10:59 PM » |
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I have just got the block back and am amazed and delighted. You can see where all the new metal has been applied to build up the missing bits of block and furnish a decent suface for the gasket. He cleaned out all the holes, fitted interference fit aluminium plugs and then cold metal sprayed on top to form an excellent and totally non porous piece of new metal all without any distorting heat. Full contact details in the Technical Information thread.Nick also does a lot of work on classic and vintage engines including crank straightening and WHITE METAL BEARINGS. The block cost me a couple of grand, of which £900 was making and fitting the plugs, but I am asure that is much cheaper than a new block! Sheila's block will be next but I shall do a lot more preparration myself first.
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« Last Edit: 04 August, 2015, 08:32:17 PM by davidwheeler »
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David Wheeler. Lambdas, Aprilia, Fulvia Sport.(formerly Appia and Thema as well).
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davidwheeler
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Posts: 1487
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« Reply #13 on: 04 February, 2016, 05:21:58 PM » |
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Well, she's back together again! Would not start though I'd checked timings several times and so dragged her down the road - nothing. Looked again at spark timing - found it some 20 degrees out (?!?) So, put that right, tried again - nowt, then noticed carb tickler sticking up so put some petrol in and success!!! I have also fitted new third gear and new cwp and new bush in starter front cover (made by Chase Engineering/Dycomet), third is fine, second suddenly rather noisy and cwp silent. Must have done something right, took me quite a while to set it up. No serious oil leaks and coolant continent. Starter works again after I moved it into correct alignment with the flywheel. I have only been up to the service station for petrol but, though acceleration is a bit less she cruises at impressive speed - I have no idea how fast as speedo is set for saloon (low ratio) cwp so need to recalibrate. I find the gearbox changed and cannot for the moment change up though changing down is no problem. I find the gears on the two cars quite different though the gearboxes are similar and have probably been exchanged a few times! Now to do a few longer runs and see if all remains well but I am hopeful and it is so nice to be driving her again.
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David Wheeler. Lambdas, Aprilia, Fulvia Sport.(formerly Appia and Thema as well).
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frankxhv773t
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« Reply #14 on: 04 February, 2016, 05:38:16 PM » |
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Congratulations! Might performance improve during running in?
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