JowettTalk

Barry - a couple of thoughts on the exhaust.

Roy Bradock used to insert about 6 to 9 inches of flexible exhaust in the offside pipe to accommodate any minor discrepencies in alignment. Maybe welding in a length of flexi could be used to to enable it to clear the cross member/

The 8 hp models used cast iron stubs bolted to the cylinders and these provided a more or less right angle bend facing down. the stubs of the Y pipes were just a push fit in the iron castings. The use of two of these would perhaps facilitate taking the exhaust straight down ( and then under the crossmember.

I think it is highly unlikely that any standard Jowett Y pipe will work with the combination of 1934 engine and vintage chassis. The best way of dealing with the problem could be to make up a pattern of the required shape using stout wire and then bend pipes accordingly, perhaps using some flexi to allow for any small discrepencies in bending.

george

Firstly, Happy New Year to everyone!!

With the holidays out of the way, I have made a proper start on with the post shake down to do list. I have a nice piece of flexible exhaust with proper collars waiting to form the kink over the cross member. JCS are having wheel studs made and I already have the correct nuts and washers from them.


Given the wear on the spindle, it seemed pointless trying to sort the jetting without giving the carb a proper overhaul. I managed to order a rebuild kit along with spindle and bushes from the Carburettor Hospital. I also have the carb from JCS which is in quite a sorry state and has obviously spent some time out in the elements, the strangler flaps having rusted completely off. After a bit of a struggle, I did manage to liberate the jets and the body looks salvageable, so I maybe able to rebuild it as a spare at a later date.
Given the specialist job in hand, I obviously called in an expert and he now has the original carb stripped down ready for our trip to his Uncle Ian's workshop and the ultrasonic cleaner, Removing the worst of the Red Hermetite revealed the choke size is 25, which does at least seem to be correct.
I have passed on my top tip for carburettor and gearbox rebuilds, which involves using a 2 quid roll of heavy duty lining paper to provide 50 ft of clean bench. I'm not sure if it went in, but hopefully my warning about screwdrivers slipping on very tight screws, just before stabbing myself through the hand will have taught him something.
One thing I have learned reading up on these carbs is that they never had a float bowl gasket, so my concerns this was contributing to the poor running were unfounded.

Another problem to sort post test drive is leaking rear axle oil. When I originally stripped the rear brakes, the drums were packed (and I mean packed!) with solidified oil. I cleaned everything up and fitted new felt seals from JCS. When the team took the drums off to measure up for replacement wheel studs, it was clear that oil is once again finding its way out of the axle. Given we'd probably only been a couple of miles at 15 mph, this doesn't bode well. The filler plug on the diff is positioned so it can't be overfilled and I have used Morris Oils SAE 140 gear oil, so it's pretty thick. Is this a know issue, or am I missing parts? My only thought is if it's going to be an ongoing problem, could I fit modern sealed bearings?

Barry wrote:...and fitted new felt seals from JCS. When the team took the drums off, it was clear that oil is once again finding its way out of the axle, even using 140 gear oil, so it's pretty thick.

Hello Barry.
I use Castrol Hypo 90s in the rear axle, and haven't had any problems, so I can't see why your oil's leaking into the brakes.
Perhaps George can give us some reasons why this is happening.
I have used felt seals which I made from a sheet of some very dense felt bought many moons ago from a mill somewhere in Yorkshire.
I've posted 4 circles of this off to you this afternoon, (2nd class), which you will have to shape etc. with a pair of scissors, then try again and see what evolves.
Perhaps only one thickness will be necessary, but 'belt and braces' doesn't go amiss.
The centre hole is made by the largest cork-borer I have, but it might just give you a start with a pair of sharp scissors.
Regards, and a Happy New Year to you and the 'Team'.
Tony.

Thanks Tony, that's very kind. Hopefully I can make it to Tewksbury and buy you a beer as payment!

I have to admit, I didn't take much notice of the setup when I replaced the original seals. They were completely hardened and had shrunk, so I just replaced them with the JCS ones while I was cleaning everything and put it back together, assuming I'd solved the problem. Now I think about it, I don't remember anything holding them in place, so I assume they are just crushed slightly between the hub and bearing, but this would mean the whole seal would turn with the wheel, rather than the shaft turning in the seal and that' doesn't seem right to me.

Hello again Barry.

I've had a chat with a very knowledgeable 'Pre-war' friend about your problem.
I wondered if there was some sort of small hole in the diff. casing to allow pressure out, but have never seen one, and he agreed there wasn't such a device.
He mentioned two things you might try. These are only suggestions, and you'll have to make-up you own mind about following them.

The first is the easy one: It's not necessary to fill the axle until the oil drips from the lower plugged hole. Because the crown-wheel runs so close to the inside face of the diff case, the wheel needs to be only just dipping into the reservoir of oil for it to throw the oil all around the inside. This means that you only need the amount of oil to allow this to happen. A way of measuring the depth of oil is by using a plastic electrical tie as a dip stick through the filler hole.

The second method is one you have touched on in a recent post, and that's the fitting of sealed bearings. This could be the method of choice, and if the old bearings come out easily, then you're ok, but if they're difficult to remove, you'll have a job on your hands.

I posted a piece about this when Marcel in Germany was asking a similar question - see Pre-war section topic 1936 Jowett in Germany Restore Tuesday November 11th 2014.

When you have removed the bearing and are replacing it with a sealed type, I'm told that it is important to use 'bearing seal' around the outside circumference as the bearing is being fitted. This should prevent oil flowing past the bearing into the brake area.

Perhaps using the new JCS felt washers will give a belt and braces approach.

My contact has often used bearings from SPEN BEARINGS in Yorkshire, and has always had good service.

Hope this helps.

Tony.

Or use a modern lip seal. Rich

Yep. I used a modern lip seal at one end of the gearbox on my Long Four. I sealed it in place with a silicone sealant - no trace of a leak since (Yet anyway!).

Just shows how behind the times I am.
I wondered if Richard was having a joke and suffering from chapped lips, then Ian came up with the same solution, so I Googled lip seal: http://www.skf.com/uk/products/seals/in ... index.html is one such source.
It all looks rather complicated, so how would you use this type of seal in the pre-war back axle instead of a bit of felt and keep the original bearings in place?
Over to you.
Tony.

The SKF seals you linked to are used on the post war Jowetts on the timing cover, crankshaft rear, front wheels and can also be used in place of the felt ones on the diff pinion and rear axle.

I'm bowing out of this discussion, but will look forward to seeing how the seals are fitted to stop the oil seepage.
Hopefully someone will provide an 'idiot's guide' that we all can follow step by step.
When it's all sorted, I might even consider such advanced technology for 'Mary Ellen' and 'Sarah Jane' if it's ever needed.
Tony.
Barry I have sent a PM.

Tony: -

Lip seals are not a universal solution, but where they fit - or can be made to fit - they work!

When replacing an earlier type of seal there are a few basic considerations: -

The moving surface should be circular and flat (parallel) although slight scoring is not usually a problem.

The fixed surface should also be circular and be wide (long / thick?) enough to take the body of the seal. Different thicknesses / widths MAY be available.

THEN select a seal of the appropriate outside and inside diameters. There are usually at least two different IDs for a given OD. The flexible lip can accommodate a surprising variation in 'tightness' on the moving element.

Fit the seal the right way round (gaiter spring or 'open' side towards the fluid). The seals usually have a 'soft' outer surface which ensures a fluid-tight seal, but if necessary seal the OD with a silicon sealant. A SMALL slackness MAY be overcome with a LITTLE more sealant, or try a shim.

Reassemble as usual thereafter.

Has anyone had any problems with this arrangement - apart from, on reflection, unsuitable applications ?

Thanks for all the suggestions. I'm afraid I haven't investigated the seals any further as it's been a bit too cold to push it out and start jacking it up! I getting near to another road test and I'd like to change the wheel studs, so this will be a good chance to measure up and see if lipped seals will fit in place of the felts.

We have made some progress, despite the weather. I cut a section out of the nearside exhaust and with the aid of a friend with industrial pipe benders, tweaked the manifold pipe up to clear the cross member. A complete success, other than the off side, now being free to sit flat on the cylinder, dropped down and hit the cross member instead. Solved by cutting a section out and bending that side too, so I now have flexible both sides, which I am happy about as it does mean there's no stress at all due to the chassis flexing as the silencer, is completely isolated from the front section.
In other news, the carb spindle is now rebushed. The bushes supplied were a bit oversize, but it's all been tweaked and reamed to size. Matthew has put all the bits through the ultrasonic cleaner at a friends workshop, but afterwards he confided in me that he has no idea where all the bits go which is a bit of a worry. Better news is that the jets in the old carb from JCS should see us nearer original spec and as the rebuild kit contains pretty much everything including float needle valve and even a new slow running screw and it's spring, at least if I have to play with jet sizes, I'm not trying to correct wear and tear.

One thing I have been pondering is my rather free flowing exhaust system. The new Y piece is probably 1/2" larger diameter and the impressively large silencer, pretty much straight through. I've notice the one pre war Jowett I have seen and most other cars of the era have very narrow bore pipes. Is there any reason or theory for this? I can't think back pressure would be an issue given it's a slow revving, low performance engine?

The carburettor is now hopefully restored to near new condition ready for another test run over the Bank Holiday. I've paid a fiver to take part in the local Cottenham Yesteryear Road Run end of next month, so the pressures on, even though the start line is only about 4 miles from the house, so not too ambitious.

While it's the correct model carb for the engine, I'm becoming more suspicious it could have come from something different. Once everything was cleaned and I could see the markings, I noticed the capacity tube was wrong, as well as the slow running and compensator jets. Again, the scrap carb from JCS yielded the correct size. I can understand someone changing one jet, but it seems a bit unlikely to start swapping 3 around. All the jets and capacity tube now match the sizes in the Jowett Club spec and also the spec given by Zenith I managed to find. There is a good description of how the Zentih Carb works on one of the Austin 7 sites, so at least I now understand what all the 5 jets do, which might give me a fighting chance if it's not right.

I read with interest the comments in this month's Jowetteer on getting younger people involved with the cars. Well here in Cambridge, the world famous seat of learning, we're very keen on the three Rs - reading, writing and rebuilding carburettors. Here we see the student carefully seating the tiny and delicate progression jet
And proudly showing the finished project ready for testing
The Mark 2 exhaust system is all ready for road test too and I have I hope sorted the clutch adjustment. Just the brake light switch and a couple of bits and bobs and we should be good to go