Tank Restoration

[old_goat]

10 hours ago, Tim the Tank Nut said:

we did a lot of testing.  The old engines I was responsible for wouldn't tolerate multi weight oil.  It had to be straight SAE.  I talked to various oil manufacturers.  We made a mechanical oil test gauge assembly for our engine stand.  Different oils behaved differently at the same RPM and temperature.  At the time we could get Castrol in straight weight and that performed the best.  We had such bad results from Pennzoil that I called them and got a tech guy on the phone.  He had a lot of info but nothing definitive.  Modern oils are certainly designed for modern engines.

The dutch guy (Master Milo) who restored a Type 69 tank has a kind of sponsorship with an oil company, and a while ago, they were also discussing about what oil to use in the tank. They also said that modern oils for modern engines are not really suitable, so they recommended something specific (I do not remember exactly). But it is also true that the oils manufactured recently are higher quality than back in ww2, or even in the '80s, and if the correct one is used, prolongs the engine life. 

[old_goat]

17 hours ago, alejandro_ said:

(*) A Czech company has been hired to restore a Ju-87 Stuka

I REALLY hope not to flying condition! If that is the case, the Stuka is a goner unfortunately...  This madness needs to stop once for all. 

[Stuart Galbraith]

Well, there is a Stuka in America that was being restored to flying, although to be honest it was pretty much a replica anyway.

There is a lot of Luftwaffe aircraft that I would like to see flying, a Stuka really isnt one of them. By my Grandfathers got bombed by them, and I read too many stories of refugee columns being bombed by them. Its the same kind of cluelessness that has people dress up in SS uniforms.

[Stuart Galbraith]

Re engine oil, this was amusing. I suspect it was just a design study rather than a serious proposal.

https://mecheng.ucl.ac.uk/gdp/wp-content/uploads/sites/13/2018/06/4th-year-poster-2018-Project-Tiger_reduced.pdf

 

[old_goat]

8 minutes ago, Stuart Galbraith said:

Re engine oil, this was amusing. I suspect it was just a design study rather than a serious proposal.

Cool. Panzer Farm is actually doing the same 3D digitalization for lots of components, not exclusive to Tiger. But they are also preparing to manufacture new parts and even whole transmissions based on these 3D models. The australian Tiger I will be powered by a brand new built HL-230 and transmission according to plans. Panzer Farm is also doing research to prolong component life, one example is clearly seen on the recent Saumur video, the pistons are treated with a special compound to reduce wear and improve combustion. 

[Stuart Galbraith]

That certainly IS a better solution than just dropping in a caterpillar engine, as Oz Armour seem to do with disappointing regularity. My only concern is that there is enough original engines and parts remain that someone 200 years down the line can go to a Bovington German tank and examine it, and dont come up with unrealistic understanding of what a WW2 german tank could do. You know, stamp a new date on all the parts you replace so its fairly clear when they have been reengineered to a new spec. That kind of thing. Even keeping containers of 'old' parts so we know what they were really shipped with.

But keep them rolling, I really dont have a problem with that.

Speaking of Bovington tanks, I thought this was interesting. I hope the Panzermuseum kept it running.

 

[old_goat]

53 minutes ago, Stuart Galbraith said:

That certainly IS a better solution than just dropping in a caterpillar engine, as Oz Armour seem to do with disappointing regularity. My only concern is that there is enough original engines and parts remain that someone 200 years down the line can go to a Bovington German tank and examine it, and dont come up with unrealistic understanding of what a WW2 german tank could do. You know, stamp a new date on all the parts you replace so its fairly clear when they have been reengineered to a new spec. That kind of thing. Even keeping containers of 'old' parts so we know what they were really shipped with.

But keep them rolling, I really dont have a problem with that.

Speaking of Bovington tanks, I thought this was interesting. I hope the Panzermuseum kept it running.

 

Exactly. I 100% agree with everything. 

I'd add one more thing. I think it would be a good idea to start this 3D digitalisation for cold war stuff too. While vehicles like Chieftain, M60, or even T-55 are not yet "endangered species", but in a few decades they will be. Better start as soon as possible.  (Hewes is already having problems getting parts for the M60's engine)

Edited July 17, 2025 by old_goat

[Stuart Galbraith]

Well watching that channel, there are already parts that are hard to get or unobtainium, even for Chieftain. Granted you could probably get most of them if you went to the graveyard in the Iraqi desert, but not really worth earning an orange jumpsuit for really.

 

[nitflegal]

On 7/17/2025 at 3:28 AM, old_goat said:

Cool. Panzer Farm is actually doing the same 3D digitalization for lots of components, not exclusive to Tiger. But they are also preparing to manufacture new parts and even whole transmissions based on these 3D models. The australian Tiger I will be powered by a brand new built HL-230 and transmission according to plans. Panzer Farm is also doing research to prolong component life, one example is clearly seen on the recent Saumur video, the pistons are treated with a special compound to reduce wear and improve combustion. 

My earnest hope is that the scanners are getting effective enough and cheap enough that this will be more widespread for restorations.  The parallel issue with restorations right now is that parts for anything pre-1970's are becoming really difficult to find for very common western vehicles and damned near impossible for anything else.  Which is driving a lot of restorations to be non-runners simply because while you can machine replacement parts for a Pershing or Cromwell it makes the costs explode to the point where it's just not viable.  Outside of a few extremely wealthy collectors where money is no object like the late Jacques Littlefield turning a 50K restoration into a 50k restoration with an optional 40k to machine non-existent parts turns that into a static display.  Pershings are the perfect example.  Running Pershings went out all the time 10-15 years ago, now you're seeing them out far less often as lots of engine and suspension part supplies have dried up and everyone is babying theirs.

[old_goat]

6 hours ago, nitflegal said:

My earnest hope is that the scanners are getting effective enough and cheap enough that this will be more widespread for restorations. 

As far as I know, the scanner is the least expensive thing. Most museums would easily afford it. Turning the scans to accurate (from engineering point) 3D models is far more expensive (lots of work). Then, some smaller parts can be easily and cheaply manufactured using CNC machinery. But sadly this is the minority, most stuff requires either casting, and/or special 6 axis milling machines, and this is when things get damn expensive.  

[shep854]

Not only military vehicles...   I have a friend who had to finally let go of a mid-'60s Mercedes sedan because parts became impossible to find.

[old_goat]

In today's post on Wheatcroft's facebook page, he mentioned engine restorations... Quite amazing. Rather high numbers. Thats the only way to reduce costs. They also plan to start producing spare parts.

"We are often asked whether our vehicles run original engines or modern replacements. 100% we only use original engines. We are very close to finishing one of our major vehicles being restored in Germany, once that vehicle is out of the workshop and back in our Collection, we start a massive programme of restoring our Maybach HL 42 (25 in number), HL 62 (20 in number), HL 108 (2 in number), HL 120 (25 in number) and HL 230 (12 in number). If there are any remnants that are not serviceable it is our intention to restore a number of engines purely for display. This way none of the components will ever be wasted. Once this initial batch of engines are restored, we will start a long slow programme of re-engineering pattern parts. This is so that we can start the restoration of some of our incomplete engines. As time progresses we will end up re-engineering complete engines. At the moment we produce something around 10-15% of new made parts. By the end of this initial production run, we envisage new parts in the order of 25% so you can see how all of a sudden we make a quarter of an engine brand new. So we are already on the road to producing full authentic working reproductions. This is something we have done in the past with some of the worlds most complex engines, such as the Bugatti Royale, Mercedes 770K, Mercedes-Benz W125 Grand Prix engines and BRM V16 Grand Prix engines. So, we feel confident that in the future everything we can restore will run authentic or at least part authentic, engines. This same engineering practice will be adapted to axles, differentials, transmissions, steering gearboxes, etc, etc. Without a doubt it’s the future, the only way to go. We know of certain engines that are running on an annual basis and the operators literally have their fingers crossed that the engines don’t fail. I think within 24 months that worry will disappear when our parts become available."

 

Edited July 20, 2025 by old_goat

[DB]

Leno's garage shows him using scanned parts to allow for maintenance on wildly old machinery - I think the example I saw was a YT video about replacing a broken casting from an antique carb, where they had the two broken parts, scanned them, reassembled them in CAD and printed a new part using laser sintering. (Although they could have produced a buck and mould from the CAD instead, which would probably be more useful if they wanted a small production run rather than a one-off.)

 

[alejandro_]

1 hour ago, DB said:

Leno's garage shows him using scanned parts to allow for maintenance on wildly old machinery - I think the example I saw was a YT video about replacing a broken casting from an antique carb, where they had the two broken parts, scanned them, reassembled them in CAD and printed a new part using laser sintering. (Although they could have produced a buck and mould from the CAD instead, which would probably be more useful if they wanted a small production run rather than a one-off.)

When doing 3D scans I wonder what they do with the tolerances if they do not have any drawings. I guess that if it is out it won't matter so much as the vehicles are not going to be doing many miles ie you accept the engine will lose more oil for example.

[Stuart Galbraith]

There is a locomotive under construction in the UK, a Patriot. Anyway I remember at an early state they had a problem with the cylinder blocks, since the patterns to cast them were long gone, and making new out of wood was cost prohibitive. So they took the 3d drawings they got from the original engineering drawings, 3d printed some blanks appropriately oversize to allow for shrinkage, then used them to cast new ones. For low volume components that need casting, there is probably a lot of things you can do like that.

https://lms-patriot.org.uk/

[DB]

13 hours ago, alejandro_ said:

When doing 3D scans I wonder what they do with the tolerances if they do not have any drawings. I guess that if it is out it won't matter so much as the vehicles are not going to be doing many miles ie you accept the engine will lose more oil for example.

It's a good point when you have only one worn out part to work with - the classic problem with reproducing items without the proper data package.

I imagine that everything is hand fitted - the example I made was old enough that the original part may also have been fettled to fit.

BAE Systems were supporting Tornado towards its EOL with 3d printed parts, but one imagines that they had access to the original drawings.

[Stuart Galbraith]

I notice the old TV series tank overhaul is now up on YouTube.

 

[Stuart Galbraith]

And here is the thread about restoring the engine, yet to run 9 years later...

https://hmvf.co.uk/topic/23036-iwm-duxford-centurion-mk-iii-that-one-off-the-telly/page/3/

[nitflegal]

On 7/19/2025 at 4:54 PM, old_goat said:

As far as I know, the scanner is the least expensive thing. Most museums would easily afford it. Turning the scans to accurate (from engineering point) 3D models is far more expensive (lots of work). Then, some smaller parts can be easily and cheaply manufactured using CNC machinery. But sadly this is the minority, most stuff requires either casting, and/or special 6 axis milling machines, and this is when things get damn expensive.  

You would be correct, but I've found it a surprisingly difficult thing to convince the average museum to spend $500 for a "nice-to-have" never mind that then you need relatively expensive software and someone who can use it.  However, to your point I would hope that we have more museums just scanning stuff for documentation.

[Stuart Galbraith]

Well its not a tank engine, but it killed enough tanks in its time, so I'm not going to apologise. God knows how they are going to get it to run, but I want to hear it when it does.

 

[alejandro_]

On 7/21/2025 at 11:26 AM, DB said:

BAE Systems were supporting Tornado towards its EOL with 3d printed parts, but one imagines that they had access to the original drawings.

IIRC it was being done to test 3D printing as a method, and applied in parts which were not that critical, for example a radio panel

On 7/23/2025 at 1:48 AM, nitflegal said:

You would be correct, but I've found it a surprisingly difficult thing to convince the average museum to spend $500 for a "nice-to-have" never mind that then you need relatively expensive software and someone who can use it.  However, to your point I would hope that we have more museums just scanning stuff for documentation.

We looked at 3D scanning in my company (mechanical engineering/manufacturing). Apart from the scanner you would need a CAD software that can process cloud data (measured by the scanner), and the licenses are usually expensive. There is also the question of having someone who is trained on this. 

I think it would make more sense to use a contractor. The company we contacted had 3D scanned a Merlin engine by the way.

[sunday]

SpaceX makes extensive use of additive manufacturing in rocket engines, famously on the Raptor 3

https://en.wikipedia.org/wiki/SpaceX_Raptor#Raptor_3

Edited August 1, 2025 by sunday

[old_goat]

2 hours ago, Stuart Galbraith said:

Well its not a tank engine, but it killed enough tanks in its time, so I'm not going to apologise. God knows how they are going to get it to run, but I want to hear it when it does.

One of the most interesting engines ever made. I love it. But I REALLY hope it will not go into a Tempest, Typhoon or anything to make the damn thing airworthy, so that it will eventually crash! 

[Stuart Galbraith]

10 minutes ago, old_goat said:

One of the most interesting engines ever made. I love it. But I REALLY hope it will not go into a Tempest, Typhoon or anything to make the damn thing airworthy, so that it will eventually crash! 

Yeah, its going into a Typhoon recreation.  The whole channel has some wonderful  engineering in it.

Well.. there is currently a Tempest II flying at the moment, which im more worried about when thinking about the kind of legacy the Centaurus has in Sea Fury.

 

[DB]

3 hours ago, alejandro_ said:

IIRC it was being done to test 3D printing as a method, and applied in parts which were not that critical, for example a radio panel

That's my recollection, too. The first parts were a switch panel. Even though it's not a structural component, it could still take a plane out of service, so still very useful.