WW1 Thornycroft restoration

[shane.c]

Keep the info and pics coming,

[Minesweeper]

A day of slow and steady progress – I have been cleaning all sorts of bits – including the Oil Filter. This is interesting and of quite a different design from the previous ones that we have encountered – it is of a long tubular design and sits in a channel along the bottom of the sump.

 

 

 

 

Tony has been making and fitting more studs. That’s the 5/8” and ½” ones out of the way for the moment - until the next lot come along – and now it is down to many 3/8” ones – all for the Crank Case and will be needed for the engine reassembly.

 

 

Tim

[Minesweeper]

My last whole day in Devon before I return to Oxford tomorrow - we decided to carry on with the preliminary cleaning of the engine bits so that we could see exactly what we had there and what will need to be done.

 

We picked up the Oil Filter first of all after it had a chance to dry out from yesterday’s efforts on it – it had cleaned up pretty well but there was still some small bits of muck caught up in the mesh and also inside it and an air hose from outside and then from inside sorted that out – and it really is now ready to fit again.

 

It was also a chance re-appraise the other bits that I did yesterday to see how the looked.

 

 

 

 

 

We picked up the pistons then to have a go at them – just to see what we have there. You will re-call that they had to be jacked out of the cylinders as they were seized – and as we anticipated they were pretty untidy with the piston and scraper rings unsurprisingly mainly stuck. The usual paraffin bath was successful with all the scraper rings and they freed up – work on the piston rings brought mixed results with the three rings in one cylinder totally freed up – but in pistons nos 2 and 3, we freed two rings but broke one in each of those pistons. As far as the fourth piston was concerned, although the scraper ring came clear, all three piston rings are stuck so we have left that one stewing in some Plus Gas for the moment and will try again in a day or two.

 

 

 

 

 

 

[Minesweeper]

We decided then to have a go at the Cam Followers – they were all very dirty – but mainly cleaned up well. They are all free but the threads will want cleaning and they will require new caps as those are badly corroded.

 

 

 

 

 

 

The final effort was on the oil pipe – we really had no idea what that was like under all the congealed grease and dirt – but cleaning the muck off revealed a nightmare! It had obviously been badly repaired during its life time – it is cracked and it looks as if it has been sealed with sticky tape. The elbows and other brass fittings will probably live to fight another day but new pipe work is called for!

 

 

 

 

 

 

[Degsy]

Some good news and some bad then Tim, Bodgit and Scarper have sure been at that oil pipe.

[Gordon_M]

Tape ? When was the last time you think this may have been run ? It does sound a bit like Scrapyard Challenge

 

tape - shakes head again.:shocked:

[8_10 Brass Cleaner]

It looks like solder tape.

[Chris Suslowicz]

It looks like solder tape.

 

My thought was "lead flashing", but I suspect the self-adhesive stuff (bitumen coated on one side) is too recent.

[nz2]

The tape you refer to does look like a lead based material. That piece of workman ship, although looking some what rough is a fine example of a older style of repair that has lasted many years. I was about to add the words " in service", but then realized the engine may have only run for a short period after this repair and the engine laid up. That does not mean the repair failed and was the reason the engine was laid up. This is a nice example of a repair or modification ( improvement) that so often gets removed in a restoration as the standard becomes factory finish. Doug

[Great War truck]

In the previous note, we reported that we had completed some preliminary work on the Cam Followers. The first two pictures here show the Cam Followers that were in the complete engine and you will notice that they do not look in quite the best condition!

Fortunately, the Cam Followers were still in the half-engine and they are in a significantly better condition - although the caps on those are badly corroded. We plan to use those in the reassembly of a complete engine but the caps will have to be replaced.

But the caps on those from the complete engine have been taken off and may well be substituted for the corroded ones as they are not too bad.

The other two pictures in this sequence show the better caps but you will notice that they have been quite dented through "hammer blow". There is still plenty of metal there and we must make up our minds as to using them - or replacing them! We do like to use original parts where we can.

 

http://i30.photobucket.com/albums/c309/Greatwartruck/Thornycroft J Type lorry/DSCN6149.jpg

 

 

 

These are the corroded caps that have to be replaced. In the second picture, you will notice that the fourth one from the left has been replaced in the past by a "temporary" arrangement!

 

Edited December 29, 2023 by Great War truck

[Cel]

Looking good so far! Is it an option to weld up the dents and grind/machine them down to original specs?

 

Marcel

[Minesweeper]

We think just grind them back as they are if there is enough metal there - we need to have a closer look first of all! The top certainly must be made flat.

 

Tony

[mattinker]

We think just grind them back as they are if there is enough metal there - we need to have a closer look first of all! The top certainly must be made flat.

 

Tony

 

This sort of thing is quite often finished with hard casing, if there's enough metal, Casenite or something similar after grinding preferably with a tool-post grinder) and polishing. If there isn't enough metal, but enough to weld, a hard facing rod would do the job. I would see a welding rep for someone like Castolin Eutectic. Obviously practice first or farm it out! My Castolin rep (here in France) will give me samples if I only need a small amount, although it might be to get custom!

 

Regards, Matthew

Edited April 11, 2012 by mattinker

[Minesweeper]

This sort of thing is quite often finished with hard casing, if there's enough metal, Casenite something similar after grinding preferably with a tool-post grinder) and polishing. If there isn't enough metal, but enough to weld, a hard facing rod would do the job. I would see a welding rep for someone like Castolin Eutectic. Obviously practice first or farm it out! My Castolin rep (here in France) will give me samples if I only need a small amount, although it might be to get custom!

 

Regards, Matthew

 

That's interesting Matthew - thank you! Not all of the caps are as bad as the two illustrated - and I wonder if it is a case that the hard casings on those two have worn away - whilst the others are still complete and hence the lack of any significance wear on them?

 

Steve will be here in Devon this weekend and I know that he will be keen to see them before any action is taken! His home computer is down at the moment and I am not sure how up to date he is with all of this!

 

Tony

[Gordon_M]

I would expect those to be hardened. They will weld up just fine but after grinding flat will need case-hardening again.

 

You night want to do one and check if the internal thread distorts though.

[Asciidv]

A question for the Master Stud maker.....

 

I would imagine that the stud holes are a mixture of through holes and blind holes.

 

1. On the blind holes are you screwing the studs in until they bottom out at the end of the tapped thread?

2. On the through holes are you screwing them in until you bottom out on the end of the thread on the stud?

3. OR, are you taking advantage of something like Loctite 270 'Studlock'?

 

and now a question for the Master Engine Block Painter......

 

1. Do you have any reservations about gasketing (if there is such a word) onto painted metal rather than the gasket having direct contact with the metal face?

 

I saw your broken rings and I think we will all be disappointed if you do not make your own replacements. I have just taken the easy way out and had 25 made by the 'Bradford Piston Ring Company' based in Manchester. A superb old style company who made these rings to my specification and only asked for payment once I had received them. They came within 2 weeks too.

 

Looking forward to Brighton 2015 for the Thorny's first run!

 

Best wishes,

 

Barry.

Edited April 12, 2012 by Asciidv

[Minesweeper]

A question for the Master Stud maker.....

 

I would imagine that the stud holes are a mixture of through holes and blind holes.

 

1. On the blind holes are you screwing the studs in until they bottom out at the end of the tapped thread?

2. On the through holes are you screwing them in until you bottom out on the end of the thread on the stud?

3. OR, are you taking advantage of something like Loctite 270 'Studlock'?

 

and now a question for the Master Engine Block Painter......

 

1. Do you have any reservations about gasketing (if there is such a word) onto painted metal rather than the gasket having direct contact with the metal face?

 

I saw your broken rings and I think we will all be disappointed if you do not make your own replacements. I have just taken the easy way out and had 25 made by the 'Bradford Piston Ring Company' based in Manchester. A superb old style company who made these rings to my specification and only asked for payment once I had received them. They came within 2 weeks too.

 

Looking forward to Brighton 2015 for the Thorny's first run!

 

Best wishes,

 

Barry.

 

A wonderful lot of questions, Barry!

 

The first set of questions.

 

To question 1 - they are all blind holes - apart from the four for the studs with the long fancy extended threads on - but those are only threaded to a sufficient depth to accomodate the larger thread, and then left as an unthreaded hole for the extension to pass through. The length of the new studs was copied from the ones taken out - but when compared with the studs still in position in the other crank case, then they are 1/8" too long. They have not been tightened right down - but they may have to be shortened on the bottom part - that will then absorb most of the part of the lower thread which is visable protruding from the crank case.

 

To question 2 - then that will be "Yes".

 

To question 3 - "No"! Should not be necessary.

 

On the second set of questions.

 

1. Something we have discussed and the answer to that one is "No"!

 

Broken Rings - we have used Clupit Rings in the past and found them excellent. The three rings on the last piston have still not moved and I really would like to get them out without breaking them. I have been dosing them with Plus Gas and I think that there may be some movement there now. We have not touched the inside of the cylinders yet and I guess that there will be a question over the sizes of all the components until they have been properly cleaned out and we can see what we are dealing with.

 

Brighton 2015 - we like targets!

 

Tony

[Great War truck]

Steve paid a flying visit to Devon this last weekend for reasons other than playing with Lorries - but took the opportunity whilst he was there to have an initial inspection of the cylinder bores with Tony, knowing that there was work to be done on them.

You will recall that the four cylinders are cast in pairs and it was one of the two cylinders in one block that we knew was going to cause us a problem. These following three pictures relate to this block - two are of the one cylinder that we knew had been open to the elements with the other picture of its mate which had been protected.

The two cylinders in the other block are in a similar state to the cleaner of the two in this first block and we would assess that there would be no problem in cleaning the three up as they are for re-use.

 

 

 

 

An initial clean of the rusty cylinder does not reveal a pretty sight - remaining corrosion in it is still proud of the original cylinder bore but it has also revealed that it is deeply pitted. This cleaning was done with a wooden spatula, a wire brush and some emery paper. It was not treated too harshly.

It appears that there will be no alternative other than to re-bore this cylinder.

Now depending on how much has to be taken off and that there is enough metal there to play with for re-boring, it will then require a new piston. Can we get away without re-boring the other three cylinders?

The cylinders are of 4 1/2" in diameter but as this is a slow turning engine, will it be significantly out of balance if one of the pistons is marginally bigger than the other three?

This is something that we have not been confronted with before and would appreciate some advice and comments on this one, please!

 

 

[philb]

Is the cylinder wall thick enough to take a sleeve? It might be retained by a lip, top or bottom. Charlie Brown of Deanfield Commercials makes new liners (certainly wet but maybe dry too) for AEC engines, machined from solid using one of the family of Meehanite irons, I believe.

[mattinker]

It appears that there will be no alternative other than to re-bore this cylinder.

Now depending on how much has to be taken off and that there is enough metal there to play with for re-boring, it will then require a new piston. Can we get away without re-boring the other three cylinders?

The cylinders are of 4 1/2" in diameter but as this is a slow turning engine, will it be significantly out of balance if one of the pistons is marginally bigger than the other three?

This is something that we have not been confronted with before and would appreciate some advice and comments on this one, please!

 

 

 

The dry liner option would appear to be interesting as there is visibly a lot of metal to take off. I would have thought that an engine of this age would have quite a lot of meat in the cylinder walls. The determining factor will be how much needs to be taken off it has to be re-bored anyway, so why not start with that and see? If piston weight is the only problem, the new piston could be lightened to make it the same weight as the others. I have no experience of running an engine with one different sized bore!

 

Regards, Matthew

[fesm_ndt]

Is the cylinder wall thick enough to take a sleeve?

 

You could measure the wall thickness with utrasonic equipment. I know a few guys in the UK that maybe can help or if somewhere by Cambridge perhaps TWI. I wish I was in the UK on a trip as I'd gladly drop by

[Thumpercross85]

It may be time to look at modern cylinder refinishing processes - and have that particular bore refinished back to size to suit the piston & rings that you want to fit in it. This process is typically used on aluminium one piece barrels and is excellent, but I think it can be applied to cast iron as well. Perhaps worth chatting to these guys with the specifics and see what they say....http://www.poetonaptec.co.uk/aptec-liners.htm

[Minesweeper]

It may be time to look at modern cylinder refinishing processes - and have that particular bore refinished back to size to suit the piston & rings that you want to fit in it. This process is typically used on aluminium one piece barrels and is excellent, but I think it can be applied to cast iron as well. Perhaps worth chatting to these guys with the specifics and see what they say....http://www.poetonaptec.co.uk/aptec-liners.htm

 

Well, thank you very much for that one - certainly something to explore! I have just been having a word with Steve about it on the phone - he is computerless at the moment so has not seen your suggestion but I do hope that he will have seen it by this time tomorrow! He is the Professional Engineer amongst us and understands these sort of things much better than Tim and I - and his first thoughts were that the deep pitting might be a problem but he will speak to them in due course and all three of us will be most interested in what they have to say!

 

But thank you for the suggestion and we will post the response when we have it!

 

Tony

[8_10 Brass Cleaner]

If the pits cannot be bored out, it should be perfectly possible to fit dry liner. You may be able to overbore and fit a liner back to standard.

 

The big problem would be deciding how 'brave' to be when deciding the OD of the Dry liner, go too far and the casting is scrap!

 

I have seen steam engine bores and barn engine bores repaired with braze. Would be quite difficult on this.

[ferret1958uk]

Where about is the severe pitting in relation to the travel on the piston? If it is below the compression rings then you will not lose compression. The corrosion looks high enough to avoid the scraper ring as well.