Starting on a warm 70 degrees F day, very briefly used my switched starter carb. Drove about 12 miles for lunch. The coolant was a steady 72 degrees C for the trip. Thirty or so minutes later the car was very reluctant to start, with no starter switch engaged. Immediately I got a strong smell of gasoline. I opened the bonnet (carefully). I couldn't see any fuel. Perhaps one of the floats in the two HD6s failed. On this forum somewhere, I have looked back to page 21, there was a post about a modified wrench to get at the airbox attachment at the firewall. Suggestions as to how to remove the airbox will be appreciated. When I first got the car last January I purchased rebuild kits for both carbs, and the kits have the float valve and seats. In the event the floats are not right, they are on order. Since the car runs very well the floats, valves, and seats are as far as I need to go with the carbs now.
Thank you for the wonderful support I have been getting on this site! Regards, Morgan

 

Presume you mean the Plenum chamber or Aircleaner. We associate the airbox with the ventilation system.

 

Member JeffR1 usually has bent & purpose made spanners. Send him a PM or wait for him to notice your post. He is prolific on this forum.

 

If you mean the kind off plenum thing that attaches to the two carbs, I took mine off the other day. I used a normal 1/2 inch AF open ended spanner. You can't swing the spanner very far, which slows the process down, but there are only two bolts and they don't need much force. Certainly, there's no space for a ring spanner, socket or adjustable. Unless you plan to do the job on a regular basis, I'd not bother with making a dedicated tool.

 

Before drafting my request for information about how to remove the air intake (P/N C16476, Plate 12-10, Publication J24), searched the posts back to 2017 because I remember seeing one about how to remove it. I am not confused with the heater box. My dim recollection about the post I was looking for was by JeffR1. I have not done personal messages before, but I am going to learn how and send JeffR1 a message. The fuel lines from the fuel pump to the carburetters, including the sediment trap, were cleaned and the fuel pump serviced, along with a new fuel tank. The sediment bowl had about a quarter-inch of slime in it before it was cleaned.. Once the air intake is removed I can service the carburetor.
What does the community think about replacing the complete air intake with two K&N 56-1400 pancake filters? The complete air intake can be stored to put back in the car when my estate sells it.

 

K&N's are not efficient filters, they let a lot of dust through into your engine.

I knew of a guy on the Jag-lovers site who ran a racing team and prepared two cars for a season. Identical, except one ran a quality paper filter, the other K&N. At the end of the season, the engines were torn down and remeasured. The engine with the K&N had bore wear that was visible to the naked eye, the engine with the paper filter was as built. His comment was that a K&N only kept out "boulders".

 

Thank you, Peter. Are there only two bolts holding the air intake to the carbs in the outside bolts of each? With the air intake still attached my fingers and a small light, there appear to be bolts on the inside of each, and the SU Workshop Manual shows two bolts on each of the intake flanges. I will rejoice if only the two outside bolts have to come off. I have a small 1/2-inch open end that fits the outside bolts.
The box spanner for the seating in the lid of the float chamber is called to be 8.58 mm or 0.338 inches. Do you know how this size came about? The closest fractional spanner is 21/64, or 0.328. 11/32 is 0.345... A better fit and I have an open-end wrench about five inches long.
By the way, I just finished watching Inspector Morse episodes. Oxford is a beautiful place.

 

Thanks for the information, Jagboi64. Thanks to Peter's reply it looks like getting the air intake removed is routine with only the two outside carb bolts to come off. I will stick to the stock air intake. Regards, Morgan

 

The SU carbs are all BA or BSF/Whitworth sized fasteners. They are not sized in "across flats" measurement, like SAE inch sized bolts. This also applies to the Dunlop brakes, and the nut for the upper timing chain adjuster, which is 7/16" BSF.

The float chamber lid is probably 1/8 Whitworth or 3/16 BSF.

Some conversion tables are here: https://www.baconsdozen.co.uk/tools/...n%20charts.htm

 

The conversion tables you sent are now saved, and very much appreciated!

 

Now you'll need to get yourself a set of British wrenches and sockets. If you're feeling wealthy, Snap-On makes them, and more economical wrenches are made by King Dick https://www.kingdicktools.co.uk/index.asp

 

King Dick are (or were) ace quality. I bought an old adjustable from an antique market. It's the nicest shifting wrench that I've ever used, well made with very little free play. I've read that several F1 teams use King Dick.

 

What you need is one of these. Made for the American market as one end is Imperial and the other end is Metric.

 

I was one of the first ones to see your post, I found it confusing so I waited for others to answer and let them sort it out.
You talked about page 21 (page 21 ???? in a manual or some post somewhere ???).
Then you went on about a gas leak in your carbs, probably the enrichment choke and the air box on the fire wall, one has nothing to do with the other.
I'm not even sure what you're asking here as later in the post you say that the problem is solved so it assumes that you installed some new float valves and the problem is fixed ???

The vent in the fuel tank is quite small, I opened mine up and that went a long way to relive the pressure from the gas fumes that build up on a very hot day.
Too much pressure in the tank from the gas fumes build up on a very hot day and force fuel into the carbs and starting carburetor.
The vent at the top of the filler inlet is too small _ some have it in the lid, that can get plugged.
Check that the vent is free if it's in the fuel filler tube.

The size that fits the long nut on the float lids is 5/16 BSF or BS or 1/4W (the "W" is short for Whitworth). Jagboi didn't get that quite right.
There are very few sizes in BSW/Whitworth, just 5 will fit an entire car that use it, like my 51 Bentley, there are larger sizes, but they are few and far between.
Smaller ones are BA sizes, they are used on British motorcycles and such and are different from BSF and Whitworth as the thread goes by pitch and not TPI.
Some sizes can be made into Metric by re-cutting the threads as they are very close.

Look for "Britool" brand name for the BSW/Whitworth sizes when buying spanners and sockets.
Take note that you can't really use any matric wrench sizes, they will either be too tight or too loose, you need the proper BSF/W sized wrenches and sockets.
If you try, the brass nut on the float lid will be rounded off if it's very tight, or you may damage the nut if you force it on.

I am OCD about having the right tool for the job, the 1/2 standard wrench in the photo has been ground down to fit on the nuts that hold the plenum chamber on _ it goes on easily.
The British seem to like machining things where there is pretty much to room to get a wrench on, on the Bentley, some things are machined to the extreme where the corners of the nuts are even coming in contact with a given casting.
The Britool box end wrenches are made very thin, and in comparison to North American tools, the American tools are so thick they look like cheap Chinese knock-offs.
There are other odd-ball things there too, like that "spring" loaded 3/8 nut driver, the foot long 3/8 extension.
I find the 1/4 inch driver adapters and such get into tight places where other larger things simply don't fit _ they do get abused though, but they have held up.
The 3 sockets are 3 of the five BSF/W and the 1/4 inch torque bar comes in very handy to get into tight areas.

As for air box, I used the 1/4 inch to 3/8 adapter with the 7/16 - 1/4 inch nut driver socket.
That was on the end of the 1 foot extension, I also used the "spring" 3/8 nut driver.
I also took the hood off.

 

I apologize for confusing you JeffR1... Thanks helping. Page 21 refers to this forum. I saw another post about taking the air intake off of the carbs when I first started reading this forum, but I did not copy it then. The mention of the enrichment carb was part of the history of how the fuel smell happened. The leak only happens after a hot restart, not after enrichment. With the history in my initial post, the hope was that the boffins in this forum would be helpful. I am thankful for all of the comments. The original post "there was a post about a modified wrench to get at the airbox attachment at the firewall. Suggestions as to how to remove the airbox will be appreciated". Airbox = air intake in Brit speak. Perhaps you thought I meant heater box. Regards, Morgan

 

Oiled K&N air filters are crap. I have a whole test program on them vs about 20 other makes. They came bottom of the pile. They are nothing but rock & bolt catchers. Their only decent filters are their blown polyester "fleece" oil filters that Mann + Hummel make for them in Germany & rebrand. They are made for Mercedes.

Benz & Mann did a joint development program for extended drain. You may as well buy the genuine article from your Benz dealership. They are cheaper.

 

How did Wix come out? I've always though of them as quality filters.

 

Right in the middle of the group. They passed marginally over half of the dirt/debris that a K&N does. This is proprietary info. I'm not publishing the Data. I would rate them Average/Reasonable ~ Nothing special like a Donaldson or Mann. There is a reason that people like Caterpillar only use Donaldson with their branding on it. Man are Cat fussy. We make about half their global offtake right here at the Donaldson plant in Cape Town. If the Cat Pantone colour yellow is not perfect they will reject a batch. Donaldson owns a Paper Mill in the US so that they can control their media. Their nominal vs absolute measurements are amazing with a loose wrap around the pleating to drop initial debris in the canister. They control max hole size extremely well as do Mann.


Here is a K&N oil filter (fleece ~ spun polyester.) made by Mann for them.






Here is the Genuine Mercedes Benz article made by Mann

 

So for typical Jaguar application, then your recommendation is to use a Mann if available? Or the OEM Jaguar filters? I'm not aware of a Donaldson being available for either the later XK or V12 engines is there? For my X Type I have been using Ford Motorcraft oil filters. I figure the lower end of the engine is a Ford engine, a Ford filter can't be that bad.

The company I used to work for packaged Cat engines (amongst others), they were always great to work with. They had extensive technical publications which made the job of an engine packager much easier.

 

Yes ~ use Mann or the genuine Jaguar filter. That's what's in my car. (Mann + Hummel) The genuine Green & Yellow packaging generally just says Mann Filter today.

No OEM filter is going to be bad. It's not in their interests.

Donaldson is more into the big stuff although they do Toyota 4X4 filtration with snorkel. They are also the kings of hydraulic filtration both single & multi-pass along with Pall UK.