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CVRT/J60 Carburettor


SirLanceUK

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CVRT/J60 Carburettor, I am stripping one down and forgot ( I got too excited and didn't record a picture from every angle. Has anyone got one they can take 6 pictures of, every side, up and down. Also can point in the direction of the right manual that might contain the parts list and diagrams of the carb.

Cheers Lance

Edited by SirLanceUK
wanted to find the manual
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If I recall the engine is a detuned etype unit correct me if I’m wrong, I always thought how it would have changed the saber/ Spartans tourque, word of working I think they detuned it so squadies didn’t race each other and improve the lifetime of the rubber torque donuts ( cannot recall the couplings name) etc

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Hi; My Fox  CVR[w] J60 was rebuilt in the USA with high compression car pistons- overbore so the liners were removed and the cooling system could NEVER handle the engine heat. Ruined the engine basically. The original J60 operated on the edge of the military cooling system for a reason.   Newc

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I have had several chats about cooling. I have been told I am missing some plates in the bulkhead so they are down of my to do list. I am also thinking of putting an electric fan on the inside of the engine louvres for running on a  hot day (On my 3rd set of to do list) 

but this post was more about the carburettor and some pictures, as I started to remove parts without sufficient  pictures.

I have now rebuilt it and looks good, but I will be stripping it again as I purchased a gasket kit, but thought this time I would take pictures and wait for the manual to arrive. 

 

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After a run don't just switch the engine off, let it idle for a while, it's the hottest running engine I've ever encountered.

Make sure the plate on the bottom of the gearbox compartment is fitted.

It seems on every wheel of mine the bearings need a washout, as they are way too stiff, since the oil has gone thick.  12 tight bearing sets add a lot of friction and increased fuel consumption as well as engine heat,

(12 includes the idlers)
Diana

Edited by Diana and Jackie
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Going from memory the XK 4.2 Jaguar engine has dry liners with no holding lip. When a 4.2 gets to hot it pulls the liners down and then the engine will start using water. You will see a white vapour in the exhaust. Keeping that 4.2 J60 engine's water and oil cool is really important to get a reasonable life out of it. Going to a single carb spoilt the natural engine breathing no1 and 6 are poorly served, A 4.2 with 2 or 3 carbs breathes much better it gets more cool air in and is a much livelier engine. 

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The Solex carb used on the J60 is actually two carbs in one, very much the same as the Solex carbs used on Rolls B Range 6 and 8 cyl engines. No need for balancing linkages, foolproof. Also the de-tuning was necessary as one of the stipulations on the design was to be able to run on any grade of petrol available in a combat zone, hence the lower compression.

 They had good performance as I witnessed when being in a Fox on road test and the driver had it running at 95 mph, we passed everything on the road,, this was about 45 years ago now!

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The manual turned up today, thanks to Diana for the pointer, it helped me no end and my spare carb is back together and looks complete... now to strip it down and use the gasket kit.

Another big thanks to Diana for the pointer about leaving the engine idling when hot to cool. I have recently been through and topped up all the hubs and idlers, but after your post I am going to drain and refill to be sure...

now I know the gearbox should be omd90 but semi synthetic or fully synthetic in the hubs or idlers?  

 

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25 minutes ago, Richard Farrant said:

The Solex carb used on the J60 is actually two carbs in one, very much the same as the Solex carbs used on Rolls B Range 6 and 8 cyl engines. No need for balancing linkages, foolproof. Also the de-tuning was necessary as one of the stipulations on the design was to be able to run on any grade of petrol available in a combat zone, hence the lower compression.

 They had good performance as I witnessed when being in a Fox on road test and the driver had it running at 95 mph, we passed everything on the road,, this was about 45 years ago now!

I’ll second that Richard. I tried to follow a Fox from Beer to Lulworth in a Landrover many years ago and couldn’t get close. He lost me in no time.

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The friction in the hubs may not be apparent until the road/idler wheels are removed, it's not just the oil has thickened, it appears either the wrong lubricant has been added, or the oil has degraded (after years).
There is no maintenance schedule to change the oil in the hubs, hence it probably never gets changed.
I tried the oil change and it didn't work.
I had to strip and washout the hub bearings, refit them  and refill to cure the excess friction.

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9 hours ago, SirLanceUK said:

folowing on from your post "Excess Friction" as some one who does not have access to any other CVRT , readly, for comparison, how do i know what excess friction is?

I am guessing it wont "freewheel" but how do i tell?

 

Use the jacking strut to lift the road wheel. You will need to do this to change a wheel.

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I could feel it on one of the idler wheels not the other, even with a road wheel lifted it wasn't that apparent, only when I took  the wheels off and turned the hub was it clear there was excess drag.
It's caused by years old oil past its days, or in the case of the idler hub goodness knows what lubricant because it wasn't oil.

 

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  • 9 months later...

Rob,

You are most definitely in the right place. Others on the forum will be able to advise you where you might pick up a J60 inlet manifold and carb.  However, you might also want to consider getting a fuel injection inlet manifold C/W injectors.  You could either use a car ECU or a Megasquirt / Speeduino ECU.  If you go down this route, I would advise carrying a spare ECU on the boat.  The advantage of EFI is reduced fuel consumption.  I don't know if you are seeking more power or not.

John

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On 5/16/2021 at 11:15 AM, Robert Dickinson said:

Hi

hope I'm in the right place, I have a speedboat with a jaguar 4.2 engine, and would like to try the J60 inlet manifold, and Solex carb.

there is an inlet manifold on a EBay,but I don't know what Solex carb I should be looking for.

help please. Thanks.  Rob

Hi Rob,

the carb you are looking for is one of these:

https://www.greenmachinesurplus.com/cvrtj60-engine-carburettor-48nnip-5338-p.asp
 

Chris 

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