Starting a new thread for this rather than have it scattered through the "what have you been doing...."

So, after 10 years in hibernation the Bantam has a nice clean Tillotson carb. The tillotson has an adjustable main jet which was leaking through its tiny little stuffing box at the bottom. I made a new gland for this out of a cork from a Ewarts fuel tap, and it worked perfectly.

Bantam retained the plain clutch plate right through to the end in 1941. I read somewhere that it was a good idea, rather than rivet the lining to the flywheel, to just place the lining in loose. Well, after a very small mileage, I can say that it is definitely NOT a good idea, as the lining is breaking up at the rivet holes.

More later. Anyone else got a Bantam?

Ivan

Location: Wellington NZ

I don't know much about Bantum's but could it be that because they did not rivet there friction linings to the flywheel there were no holes in them. Hence a longer working life.

John Mason.

Location: Nottinghamshire

Yes it may work with an un-drilled lining, However, my present plan is to locate a Borg and Beck style plate that will fit. The splined hole looks to be a standard size so I am hopeful. Bantam used an adaptation of a 3-speed Spicer gearbox originally for Studebaker, and the input shaft is spigoted into the back end of the crankshaft in the usual manner.

I'll put up a picture or two when I find out how!

Location: Wellington, NZ

A 1938 Bantam roadster, in what looks to be restored condition, sold for US$44,000 at the Gooding's Scottsdale Arizona February auction.

Tony.

Location: Malvern, Melbourne, Australia.

I would be really happy with that for my one, but not much chance in NZ. Goodings sold another one a couple of years ago for $US90,200. From what I hear, the bidding on that occasion reached about 50,000, then two women both decided that they really really wanted it!

Just put the crankshaft back in (2-mains, plain whitemetal, counterbalanced, big-ends with scoop and trough lubrication) Should have it running again soon.

Ivan

Location: Wellington NZ

Hi Ivan, I have a friend up here in Auckland who has a Bantam, he is in the process of rebuilding the engine at present. I can put you in touch if you would be interested, the two of you may like to compare notes

Location: Auckland NZ

Job is still progressing. I had a Bantam camshaft re-ground with what is known here as the "Hec Green" profile. (Hec Green was an early NZ racing driver). Anyway, I replaced the block and head complete with pistons and rods, using the "legs all dangling down" method. All fine until I discovered that, because of the re-grind, the tops of the tappets were slightly below their guides, and the lock-nuts fouled them. So, the head had to come off after all, to remove valves, to replace the lock nuts with some that I have adapted specially. (Bantam has plain lock nuts, not split tapered). All good fun.

Location: Wellington NZ

Another complication caused by the re-ground camshaft - the valves now hit the head!
I propose to relieve the valve pockets in the head till there is no contact with the head fitted without gasket. Does anyone have any ideas regarding minimum clearance between head and valve?

Ivan

Location: Wellington NZ

Relieving the valve pockets was quite easy as (fortunately) mine is a very early Bantam with an aluminium cylinder head. I just used a router with tungsten carbide tipped cutter, and cleaned up the rough bits with a small burr in a Dremel tool. Most Bantams have an iron head with integral outlet in the form of a full length riser.

Location: Wellington NZ

Hi Ivan

Quite a few Sevens remain as true examples and unmodified, and it would have been interesting to compare a stock Bantam.
Whilst not ideal for motorway cruising regardless of economy, the original Seven valve timing is not as staid as many maintain, gives smooth operation at the speeds intended, and can achieve 50 mpg. ( See A7 Crankshaft and Camshaft Gear Timing Marking post Sept 2014) You mention “a" Bantam camshaft so presume you have another rare original. Anything more than a very moderate regrind of an Austin penetrates the hardening (and tends to go beyond street timing. No hardening is not what the makers intended, although some claim surprisingly little wear with present use).
Hopefully, the alloy head is not too corroded internally, unlike most of the kind.

Valve to head clearance only has to allow for valve heat expansion and gasket settling. Perhaps .015 above newly compressed gasket. It was customary to check with plasticene. Make your own assessment based on likely extra turns of nuts.

Seem to often hear of Bantams. Even a work colleague had one long ago. Just how many are in NZ?

Bob Culver

Location: Auckland

Yes Bob, I do have another camshaft. It is not a straight swap with an A7 cam but I think it could be done if necessary, using the A7 cam gear as well. The reground cam appears to have been hardened after grinding - hope so anyway. Another interesting snippet is that the profile of the cam followers has a bigger radius than A7. Of supposedly 20 Bantams originally imported, there are 2 roadsters, one van and one "coupe" as they call it. I also have some parts including chassis from a pickup truck. The head looks fine, and I have used it on the car before without trouble.

Ivan

Location: Welington NZ

I have the Bantam engine running, but still needs some fine tuning. Having trouble getting a good idle, although it sounds OK at over about 1000rpm. Was the Hec Green camshaft a mistake? I'll persevere with it for a while.
What gives an Austin 7 its distinctive grumbly sound? It can't be the roller main as the Bantam has white metal bearings and still sounds the same. Any comments welcome.
Ivan

Location: Wellington NZ

Sorry, I have come very late to this thread. There is a Facebook group called 'The Austin Bantam Society' which is relatively active. Might be worth you checking that out for some more specific advice...

cheers...

Location: Cambridge

Thanks Hugh. I am a member of the Austin Bantam Society, and have had one reply so far. A bit more fiddling with the engine has improved matters and I think it is now just a case of getting the carb set up correctly. Even most of the grumble has gone and now it is mainly just valve clatter. I have to fit a decent oil seal for the rear main as Bantam's slinger thing is hopeless.

On the basis that any comments really are welcome, not always the case on this Forum....

How close fitted are the main bearings? Maybe the Seven style engine with its nominal rubber mounts and light crankcase is especially sensitive to main bearing clearance whatever the bearings.
Engines should be run with the minimum advance practicable; with a stock crank even to the extent of a slight power trade off. Squish type heads are not noted for smooth combustion. Excessive advance and c.r trigger vibrations of the crank and case. Advance curves are often far from original. It is often quite simple to arrange some sort of manual override, using a mower control, bicycle gear cable etc. with the distributor spring loaded against a stop. Low advance at low revs certainly asists idle.

It is unfortunate that cams intended for racing get into road cars. Much of the pleasure of an open car is tootling along smoothly at lowish speed in top enjoying the closeness with the passing scenery. (The perfect car for the miles of Wellington city coastline on a fine Sunday!) A lumpy cam spoils things. .050” off the base circle (and thru the hardening) does not hugely increase durations and overlap provided tangents are retained, but many regrinds are more as the Williams book which can give big increase in overlap for very small lift at the extremes. This may assist with a resonant system at wide throttle and high revs but not so desirable otherwise.

Depending how much patience you have, if convinced the cam is the problem, a brief trial at wide clearance, say .020 or more, may prove.

Bantams may have fared better, but Austin alloy heads attracted the pursuit of cr which is often excessive. Overboring adds considerably to the normal cr.

Oil slingers cann be surprisingly effrective. On another car I fitted one to supplement the modern seal which used to go hard and lose effectiveness. The modern seal was so starved of oil, it promptly burned out!

I am sure Forum users will be interested in anything you learn from other sources.

Bob Culver

Location: Auckland

Have the engine idling nicely now. No noises apart from normal Austin Seven ones. The problem was just a blocked carburettor jet - thought I had cleaned them all but missed the one that feeds the two progression holes.

Other Bantam owners in the US have fitted 9oil seals to the rear main. I don't thing the seal will suffer oil starvation because the bearing, being a pressure-fed plain one, oozes its oil both forwards and backwards. Seems to be plenty of oil there.

Ivan

After quite a lot of distractions here I am back on the Bantam. After getting it all back together there was still a sharp "power rattle". As I suspected either the clutch fingers or the gearbox bearings I removed both (engine out and back again) after which the power rattle has gone. Hooray! However, I now notice another, different rattle - it is a kind of tocka tocka tocka noise when idling, which appears to come from the back of the engine. Confession time now - when I put the plug back over the top of the oil pump skew gear, I noticed that there was a fair bit of side-play in the oil pump shaft. I thought "does it really matter?" Told myself "No", stuck the plug back in and re-fitted the block. Wrong decision! Reporting this as Bantam is identical to A7 in this area so some of you could be interested. So looks like another engine strip to check this, and I'll also look closely at camshaft bearings. Such a pity as this engine does not leak oil or water - dry as a bone everywhere.

Location: Wellington NZ