Another Airborne Army Tank Part on eBay!

Thanks

Tanks!! forgive the pun, Thats a great help dont suppose its for sale or trade? PM me?

Cheers

G

Here is a pic of a Meteor 3 outlet, this explains it perfectly!

Adrian

The tank in the tail is a good idea if nothing else as ballast to counteract the thrust!
You will still need a header tank with an airspace that is above the coolant outlets from the heads though.
Take a look at the relative height of the Spitfire tank, that will be about right, it does not have to project above the rocker covers.
You dont have to flow the coolant through the front header tank, the main flow can go straight down to the rads and the header tank can tee-off the engines coolant outlets with a small pipe, the tank acting as an expansion tank and reservoir only.
This is how the Shackleton and Balliol were configured.

I`m away for the rest of the week, so will be offline :p

Pete

It`s okay mate, I was vaguely aware of the differences between them, but that`s about all! What you are saying does make sense.
The Merlin only uses the two coolant outlets at the front of the blocks, although one rear one feeds through a small-bore pipe to heat the carb intake and the other can feed a cabin heater, they do not have to go anywhere to make the system work.
I wonder if you just block off everything at the front of the heated manifolds and use the two front outlets to feed a header tank, relying on convection to give some heat to the manifolds from the rear outlets? Just a thought.
I take it the manifolds do need to be heated a certain amount. I don`t use a coolant feed through the Merlin XX back end, and in low ambient temps you get frost on the supercharger intake which could ultimately result in the carb jets freezing?

Merlin installations that use a thermostat have it fitted on the header tank outlet, before the radiator. Some just rely on radiator shutters. I do use one on the Merlin XX, but just to get it to warm up quicker, the Morris rad is so efficient that they never overheat.
None of our other engines use a thermostat.

Stuart, I checked with Retro about grinding, and you are dead right. I may be wrong about a Meteor crank actually flying. the chap who mentioned it to me said he was going to use one, but whether he actually did I am not so sure. :confused: Retro certainly did not know about it. Besides, he could have easily reground it first! (the person I`m talking about is well capable of most such jobs!)

Pete

It would solve alot of problems for me to blank off the manifold completely if thats ok? it just looks like a lot of coolant goes through it. Would I need to put a small header tank above the block outlets or can i route pipe’s straight back to the large header tank in the tail. I am going to have a 10 to 15 gallon header tank in the tail and have detachable fittings to rads in the wings. I am hoping I can run it for 10 to 15 minutes on tick over without the wing rads before it over heats?
I have mounted the oil tank just behind the firewall on the floor, it fits perfectly and is close to the oil pumps so thats one problem solved.

Not trying to answer for Pete, he knows far more about it than I, but when we put a 4B in a Comet, we simply removed the thermostat housing and blanked off the header. In Cromwell and Comet, the thermostat is in the header tank and it all worked fine.

It`s okay mate, I was vaguely aware of the differences between them, but that`s about all! What you are saying does make sense.
The Merlin only uses the two coolant outlets at the front of the blocks, although one rear one feeds through a small-bore pipe to heat the carb intake and the other can feed a cabin heater, they do not have to go anywhere to make the system work.
I wonder if you just block off everything at the front of the heated manifolds and use the two front outlets to feed a header tank, relying on convection to give some heat to the manifolds from the rear outlets? Just a thought.
I take it the manifolds do need to be heated a certain amount. I don`t use a coolant feed through the Merlin XX back end, and in low ambient temps you get frost on the supercharger intake which could ultimately result in the carb jets freezing?

Merlin installations that use a thermostat have it fitted on the header tank outlet, before the radiator. Some just rely on radiator shutters. I do use one on the Merlin XX, but just to get it to warm up quicker, the Morris rad is so efficient that they never overheat.
None of our other engines use a thermostat.

Stuart, I checked with Retro about grinding, and you are dead right. I may be wrong about a Meteor crank actually flying. the chap who mentioned it to me said he was going to use one, but whether he actually did I am not so sure. :confused: Retro certainly did not know about it. Besides, he could have easily reground it first! (the person I`m talking about is well capable of most such jobs!)

Pete

Yes, we blanked off the header completely and swapped the branch on the header for the one from a Meteor 3. This is the part that takes coolant from the banks into the header. On the Mk 3 it has an extra pipe oulet in the centre facing backward. If you look at the other end in the Centurion layout, there is a hex head bung screwed in, imagine that as a pipe outlet. This allows coolant out of the banks into the header tank. I’m saying all this from memory, I’ll check tonight and post a scan of the Comet layout tomorrow if needed.

Adrian

I understand what you mean, the 4b has the fitting for the temp sender there.What are the chances of getting a meteor III branch, does anyone have a spare? If I can get one will have to fabricate one.

do you mean you blanked off the entire outlet that the thermostat sits in? if so how does the coolant return to the rad, please see the drawing pete posted. This shows that outlet as the only pipe carrying hot coolant to the rad.

Yes, we blanked off the header completely and swapped the branch on the header for the one from a Meteor 3. This is the part that takes coolant from the banks into the header. On the Mk 3 it has an extra pipe oulet in the centre facing backward. If you look at the other end in the Centurion layout, there is a hex head bung screwed in, imagine that as a pipe outlet. This allows coolant out of the banks into the header tank. I’m saying all this from memory, I’ll check tonight and post a scan of the Comet layout tomorrow if needed.

Adrian

I should point out that the advice given r.e the crankshaft grinding /rotation, was supplied by a major bearing manufacture; personally I would have thought that the finish on Rolls Royce crankshafts (as with other components) would make this less of a problem.

It was something that came up in conversation with Stan Grainger (at Rolls Royce heritage) r.e a source of usable crankshafts ,Pete says one is flying in the UK, thats good enough for me.

Not trying to answer for Pete, he knows far more about it than I, but when we put a 4B in a Comet, we simply removed the thermostat housing and blanked off the header. In Cromwell and Comet, the thermostat is in the header tank and it all worked fine.

do you mean you blanked off the entire outlet that the thermostat sits in? if so how does the coolant return to the rad, please see the drawing pete posted. This shows that outlet as the only pipe carrying hot coolant to the rad.

The coolant-filled engine mounting rails are interesting. Was this an early (desperate) measure to solve overheating? Was also used on Conqueror tanks I think.

I’d tend to agree with MerlinPete about the oil film separating crank and bearings; any increased bearing wear would occur during starting before oil pressure had built up and the number of engine starts wouldn’t be that great by modern engine standards.

Interesting about the holes drilled in Merlin con-rod webs in Meteor engines. Was this done to prevent a mix-up use in a Merlin?

Forgot to add….. we swapped the coolant branch from the Meteor 3 too, this has an extra outlet to fit to the header tank.

Adrian

Not trying to answer for Pete, he knows far more about it than I, but when we put a 4B in a Comet, we simply removed the thermostat housing and blanked off the header. In Cromwell and Comet, the thermostat is in the header tank and it all worked fine.

Pete

I want to do away with the big outlet pipe because it hits the top of the cowling. Do you think the return pipe from the thermostat would provide enouth flow if it went straight to the rad, or will it build up too much pressure in the block? I have removed the thermostat.

Thanks

Graham

Thanks Pete

Thats a great help

Graham

The guy who stated that no Merlin crankshafts were used in 4B Meteors could be correct, but they were certainly used in the Mk III and earlier. We have one with a D numbered crank.
I know of at least one Merlin flying in the UK built with a zero-timed Meteor crankshaft. The point about grinding is an interesting one, but bearing in mind the closeness of finish, and the fact that there is an oil film between the two surfaces, I would not have though it to be an issue?
Sub-standard merlin parts could mean any number of things, even the weight of the rod for example. Merlin rods in Meteors usually seem to have a small hole drilled through the web.
Camshaft wear was the achilles heel of the Merlin (and Griffon). The roller cam was introduced by Rover to some, not all 4Bs, plus the Meteorite and M120 engines, to address this. It was not a total success however because the rollers could seize! I am sure it was an improvement though.

Cooling circuit diagram attached. (Centurion)

Pete

Apparently some Merlin parts were used in early Meteors, not sure how many or which ones.I am interested to know why the Meteor uses roller cams. I am also a bit confused by the cooling system, what does the big water connection on the top of the block connect too? is it water in or water out? It is so much bigger than the water pump connections. Would be great to see a get a drawing of the cooling system.

Meteor crankshaft
From engine No R47975
http://cgi.ebay.co.uk/merlin-crankshaft_W0QQitemZ280078713892QQihZ018QQcategoryZ2983QQrdZ1QQcmdZViewItem

Pete

I notice that a few well meaning individuals have advised the seller its probably Meteor, one of those says that substandard “Merlin ” parts were used in Meteors, can anyone shed any light on this.

The other question, as of yet without an answer, is “if the Meteor counter rotates, is the crankshaft ground in the opposite direction?”; a friend of mine (still in the industry), says that when you look at a crank journal under high power magnification you can see the direction that it was ground ,and if it was run in the other direction, it would in time tear the bearings (a bit like a rotary burr).