Redherring Posted October 13, 2013 Share Posted October 13, 2013 Leyland ST king pin construction is almost identical. The thrust bearings are German DWF. Any makers marks on your thrust bearings? Quote Link to comment Share on other sites More sharing options...
Minesweeper Posted October 13, 2013 Share Posted October 13, 2013 We have not been able to move the bottom sections of the bearings so far as they are very stuck and they may not come out until we can put the King Pins under a big press and get them off that way! So no way of reading what is on those - if anything! The top halves of the bearings are very heavily rusted as well - and if there was any mark or engraving on those, then it has long disappeared - they are very pitted! So sorry - cannot help with that! Tony Quote Link to comment Share on other sites More sharing options...
fesm_ndt Posted October 13, 2013 Share Posted October 13, 2013 but dealt with as usual with heat, Plus gas and persistence. What type of time frames you dealing with when you are trying to save the bit? Quote Link to comment Share on other sites More sharing options...
Minesweeper Posted October 13, 2013 Share Posted October 13, 2013 (edited) The answer to that one is "How long is a bit of string?" You will guess that we want to get things apart as quickly as possible - but if we want to preserve a bit and not destroy it, then we just have to keep at it until it gives in. I think that it would be fair to say that that every bit completed is one more bit towards ultimate completion. We do look forward to getting the chassis completely stripped so that it can be sand blasted and properly assessed - and then painted so that we can start putting it altogether again. Tony Edited October 13, 2013 by Minesweeper Spelling! Quote Link to comment Share on other sites More sharing options...
.303fan Posted October 13, 2013 Share Posted October 13, 2013 As quickly as possilbe can take a while. It is a skill thing, and is there a date set that it should be complete and running? with my wifes 109 i set the date for june 2009, it was on the road july 2012, so it's not bad How many specivic tools were used? I have seen the big press for the wheels, just lovely to see the old school solutions. Quote Link to comment Share on other sites More sharing options...
Minesweeper Posted October 13, 2013 Share Posted October 13, 2013 Next year, 2014 is 100 years after WW1 commenced - and we already have the Dennis and the military Autocar to take part in anything that we may think is appropriate to commemorate it. There is no way in which the Thorny can be completed in time for that - but we have said that it would be rather nice if it was completed in time for 2018 - 100 years after the end of the war. The Thorny is now well underway - Steve has been in Axminster this weekend and has made great progress in completing the machining of the pistons - there will be pictures very shortly - that exercise has gone well. So very soon, the engine can be fully assembled as all the other engine parts are ready. The gearbox is completed - new wings and mudguards have been made - new springs have been made and are waiting installation - new castings for the radiator have been made, machined and are complete - but we do have the core to make. We have new front tyres in stock - but still require back ones, so they have to be made. So I would hope that we shall see some significant progress within the next few months - and we can then assess the completion date again! Tony Quote Link to comment Share on other sites More sharing options...
Roy Larkin Posted October 14, 2013 Share Posted October 14, 2013 Next year, 2014 is 100 years after WW1 commenced - and we already have the Dennis and the military Autocar to take part in anything that we may think is appropriate to commemorate it. There is no way in which the Thorny can be completed in time for that - but we have said that it would be rather nice if it was completed in time for 2018 - 100 years after the end of the war. Tony Don't forget that you can stretch that finishing date to 28 July 1919 which is when the war officially ended with the signing of the Treaty of Versailles. Quote Link to comment Share on other sites More sharing options...
Minesweeper Posted October 14, 2013 Share Posted October 14, 2013 Thanks, Roy! A very handy reminder! Tony Quote Link to comment Share on other sites More sharing options...
Great War truck Posted October 14, 2013 Author Share Posted October 14, 2013 A few weeks ago, we received the pistons back from our good friend Andy who had kindly bored and reamed the gudgeon pin holes for us. They were just too big for our machinery. He has done a super job and the holes are a firm fit for the original pins. Unfortunately, up until now, Steve has been unable to get to Devon to finish the machining on the Colchester. The first task was to set up the means of holding the pistons to machine them. As we discussed here a while back, we decided to follow Barry’s lead and pull them back onto a spigot using a draw bar through the headstock and a dummy gudgeon pin. Steve asked Adrian where he might obtain a large chunk of steel for the purpose. ‘What, like this one?’ he replied reaching into the back of the car! Thanks Adrian. This was drilled and tapped and bolted onto the faceplate. After facing it off, Steve drilled a hole through it for the draw bar and then machined a spigot to locate inside the skirt of the piston. The last picture shows the draw-bar with the dummy gudgeon pin resting in it. Quote Link to comment Share on other sites More sharing options...
Great War truck Posted October 14, 2013 Author Share Posted October 14, 2013 (edited) This proved to be a very secure method of fixing them and the turning process was quite straightforward. Steve left a clearance on the diameter of 0.005”-0.006”. Then came the tricky bit, the cutting of the grooves. Steve was very concerned about this as he could just see the crown falling off into the swarf after the last cut! Fortunately, all went well. He used a tipped parting tool to cut each groove and then took further cuts to a known depth until the rings just fitted smoothly into the slot. The scraper ring slot was most concerning as the casting is locally thickened underneath it. What Steve hadn’t spotted until now is that our replacement scraper rings are wider then the originals and he hadn’t allowed for this in the pattern. Fortunately, after some very careful measuring to get the slot in the middle of thicker section, it all worked out OK. It only remains now to drill the radial holes in the bottom of the scraper ring grooves which Steve hopes to complete this week. Success! Edited October 15, 2013 by Great War truck Quote Link to comment Share on other sites More sharing options...
Hoseman Posted October 14, 2013 Share Posted October 14, 2013 I reckon this is all a hoax and your buying these bits from Halfords, unwrapping them and having us believe you make them.....!!! As always gents, superb workmanship and skills. The sheer ingenuity used sometimes baffles me, and I'm an engineer!!!! :bow: Quote Link to comment Share on other sites More sharing options...
Old Bill Posted October 15, 2013 Share Posted October 15, 2013 I reckon this is all a hoax and your buying these bits from Halfords, unwrapping them and having us believe you make them.....!!! I wish! I have just remembered that I need to machine the ends of the gudgeon pin bosses as well. There is a lot of work in a piston and these are relatively simple. Now, please may I have some advice? The top rings are all 1/8" thick but they are stepped such that the contact surface is only 1/16". The question is, which way up should they go or does it even matter? Your thoughts would be appreciated. Cheers! Steve Quote Link to comment Share on other sites More sharing options...
Chrisg Posted October 15, 2013 Share Posted October 15, 2013 Is there not top marked on the rings? Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted October 15, 2013 Share Posted October 15, 2013 Hi Steve, Just dug out an old technical brochure from Wellworthy and they show a stepped top ring with step to top, termed the Quickseat compression ring (top groove only), see the attached pic. These rings are really intended for re-ringing a partly worn engine, to stop the top edge catching the wear ridge. Even when honed it will still do this. Possibly not the best choice for a new bore as you have. Quote Link to comment Share on other sites More sharing options...
Stefano Posted October 15, 2013 Share Posted October 15, 2013 (edited) They look like scraper rings, also called second rings or scraper/compression rings. The wide part goes to the top. The top compression ring has a square section and it's greater contact area also helps heat transfer from the piston crown to the block. There also used to be a top compression ring with a slight cutout to the top, they were called "step dodgers" or something like that, and they were fitted to engines as a "ring job" without bothering to give the bores a hone, because a square ring would risk smashing itself against the step. The cutout of one of these is obviously less than that of a scraper ring so you'll have to compare sections to see what you have. Hope this helps Stef (oops, Richard got there before me) Edited October 15, 2013 by Stefano Quote Link to comment Share on other sites More sharing options...
wally dugan Posted October 15, 2013 Share Posted October 15, 2013 when we rerung pistons these were also called ridge dodgers for the reason RICHARD mentioned Quote Link to comment Share on other sites More sharing options...
Chrisg Posted October 15, 2013 Share Posted October 15, 2013 I think that they are stepped scraper rings and the step should be downwards http://www.caberpistonrings.com/eng/tecnica.php?sez=4tempi Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted October 15, 2013 Share Posted October 15, 2013 I think that they are stepped scraper rings and the step should be downwards http://www.caberpistonrings.com/eng/tecnica.php?sez=4tempi Hi Chris, I think you are right, because the step is greater than the example I posted, they usually use these in the second groove, to scrape the oil down. Quote Link to comment Share on other sites More sharing options...
Old Bill Posted October 16, 2013 Share Posted October 16, 2013 Very many thanks for all of your thoughts, Chaps. I bought the rings from a ring specialist after telling him what sort of engine it is and the dimensions of the current rings. I am simply planning to fit what he supplied, relying on his expertise. Unfortunately, he didn't provide any guidance notes! Looking at Chris' website, it appears that if the rebate is upwards, it is used as the top ring for dodging the step at the top of a worn bore and if it is downwards, it is a scraper ring. As we have new bores I think I might assemble them all with the rebate downwards. That way, if ever we need to replace them without reboring, we can put the new top ring in the other way up to dodge the step. Will I get any lubrication problems if I assemble them all as scraper rings? The originals are just plain compression rings. Perhaps I am being too clever! Steve Quote Link to comment Share on other sites More sharing options...
Gordon_M Posted October 16, 2013 Share Posted October 16, 2013 You are right - you might be over-solving this one. What's the compression ratio on the engine, then? Nothing too high, I assume. Quote Link to comment Share on other sites More sharing options...
Stefano Posted October 16, 2013 Share Posted October 16, 2013 Will I get any lubrication problems if I assemble them all as scraper rings? The originals are just plain compression rings. Perhaps I am being too clever! Steve Steve, Like I said, if only for reasons of heat transfer i would go with a square section top ring. Whether scraper rings are necessary at all is a mute point, and seeing as my experience of cast iron pistons and their lubrication requirements is basically nil I'm really not the right person to give advice. I'd talk to someone that is used to working on engines of this age Stef Quote Link to comment Share on other sites More sharing options...
wally dugan Posted October 16, 2013 Share Posted October 16, 2013 STEVE l think what you suggest is right for the right reason the only thing that crossed my mind is if you use the rings as oil scrappers make sure the one used as a oil control ring is like the one shown really enjoy to see your progress REGARDS WALLY Quote Link to comment Share on other sites More sharing options...
Asciidv Posted October 16, 2013 Share Posted October 16, 2013 Wally, The book that you took the scan from, seems a very interesting book. What is it called? Thanks, Barry. Quote Link to comment Share on other sites More sharing options...
Old Bill Posted October 16, 2013 Share Posted October 16, 2013 (edited) Gordon M " You are right - you might be over-solving this one. What's the compression ratio on the engine, then? Nothing too high, I assume. " I think it is about 4:1 or at least, it was before we lined the bores. I think we have lost 500cc of swept volume so the ratio will have dropped a bit. Steve Edited October 16, 2013 by Old Bill Quote Link to comment Share on other sites More sharing options...
Old Bill Posted October 16, 2013 Share Posted October 16, 2013 Thanks Stef and Wally. I guess I should have been more specific in what I ordered. I seem to have wandered into another minefield of whose existence I was unaware! The oil control ring has a continuous groove with intermittent slots to let the oil through which I think is what is shown in your book, Wally. I must drill some radial holes in the piston skirt to meet them. Another pal has just suggested that I balance the pistons. How important is this? I haven't weighed them but I did leave an extra 1/8" on the crowns to allow me to do this so it won't be too hard. Steve:) Quote Link to comment Share on other sites More sharing options...
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