Aligning Centurion engine to gearbox

[Malcolm Towrie]

We're restoring a Canadian Centurion at the Oshawa Regiment museum in Ontario, Canada.
I wanted to give an update because it's actually starting to feel like we're getting somewhere!

She's running and driving with the rebuilt Meteor we got from the States, although only inside so far due to my reluctance to get clay mud all over the undercarriage when we are in the process of cleaning and painting it.

The engine starts really well. The key is not to use that stupid choke plate (aka strangler). God knows why that is installed. All that happens is the full intake manifold vacuum acting on the carbs sucks huge amounts of fuel through the main jets and because it's an updraft carb, none of this fuel gets up into the intake manifolds because the choke restricts the air flow so much, and it all dumps down into the plenum and pours out of the automatic plenum drain tubes. Rolls Royce designers obviously weren't idiots so there must have been some logic behind the choke design but I don't know what it was.

Anyway, I have a electric priming pump installed to fill the carbs to save the hassle of using the rather inaccessible priming levers on the installed fuel pumps. After that, 3 or 4 pumps on the gas pedal (which does shoot gas up into the intake manifolds) and she fires right up.

The clutch rebuild showed the massive plain plates and friction plates were all still in spec, and only a couple of new bearings and seals were required. It works well and is much lighter in operation than I expected.

Steering, including neutral steering, also works very well, which is a relief as all I did with the transmission was remove the top covers to do a visual check of gears and shifter mechanism. All looked good and fishing around the bottom with a magnet picked up no worrying pieces, and oil was clean. The final test will be driving it around the arena to confirm that all gears are there and shifting is manageable.
One thing I noticed is that there is a shift lock-out mechanism (to prevent the selector mechanism from trying to select two gears at the same time) in the gear selector box up in the driver's compartment, and also in the transmission. So it is very important to synchronize the two lockout mechanisms so that the driver can easily select each gear. I don't think the manual mentioned this requirement.

Right now we are in external bodywork repair and painting mode. Some track guards were beyond repair so new ones were fabricated. All the side bins were really rough too so repair (cutting, patching, grinding, and painting) is in progress.

I should say at this point that, like most museums, money's a bit tight, so management encourages the use of free internal labour to fix stuff, rather that farming it out to a local fab shop. And when I say "encourages", I mean "insists". So we don't always achieve perfection, even though we aim for it.

The photo below shows our progress so far.

Even though this tank is nominally Mark 5/2, it came with the full gyro stabilizing power elevation and traverse (which I believe was a later Mark?). It looks quite intact so my personal dream is to get this working and have the only tank at the museum with functioning gun stabilizing. Time will tell.
Malcolm

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[Robin Craig]

Malcolm, great progress.

dont forget I have some lights for you here, maybe i should post them to you

[Mike Cecil]

Nice job, Malcolm, looking much better than when I saw it a couple of years ago.

I think you will find that stab was a feature for all the Cent marks.

Regards

Mike

[Malcolm Towrie]

Robin, to tell you the truth, I'd forgotten you had lights! We've just started working on the lights. Can you mail them and I'll refund the postage?

Mike, I got confused. What I meant to say is we seem to have a later style, more sophisticated stab control, not the system described in the Mk 3 tech manual. Does that make sense?

Malcolm

[Lynn Eades]

Malcolm, just to update your post #30, There are two Centurions in the south Island of New Zealand. The one I previously mentioned owned by the gold miner on the west coast, and the one John mentioned in ChristChurch (east coast) Both at similar latitudes. The Christchurch one was for sale on Trademe at one stage. I thought it was cheap, so it may have moved. No idea.

[Malcolm Towrie]

Another update: after getting the bulk of the external painting and metal work repair done, we took the tank for a drive around the arena on a very hot and dusty day. (There are separate threads showing this, I think.)
Two problems showed up: the old oil seals in the transmission and the final drives leaked, and the engine ran hot. Not dangerously hot, but at the upper range of comfort.
I confess the oil leaks from the lip seals on the transmission input shaft, the output shafts (4 seals in total), and the final drive input shafts weren't all that surprising since the tank had been gate-guarded in the late 70's, so the seals were at least 40 years old. I took a flyer because getting the transmission back out isn't a lot of work, and I knew finding replacement seals would be tough.

The overheating problem is most likely because the fins in the one rad are still clogged with an oil/dust mix. We spent hours with varsol and pressure washing trying to clean the fins and hoped for the best, but it it seems we need to do more. These are very thick 8-row rads so crud getting deep into the core is very hard to get out. I'm thinking steam cleaning now.

When's it's running again, I'll take infrared readings of the inlet and outlet temperatures of the two rads to confirm this is the problem.

Regarding the seals, we needed to find seven new seals. I found three seals of the correct size, but the other four were a problem. If the inside diameter fitted the shaft, the outside diameter would be too small. So I ended up getting the seals that fitted on the shaft and buying some mechanical tubing and machining spacer rings to make the seals fit in the housings. I'll post some pics and the seal part numbers for the tiny number of people who care.

Malcolm

[Robin Craig]

Malcolm,

I have to ask, where is your tolerance for having new stock of those seals made again at this point? I do find we are living in an age of new production of many items at very reasonable prices these days.

How is your lighting making out?