Club president Chuck Murray is putting together a tour to Geluna Gelato in Cary. The meet-up is this Saturday at 1:30pm, 111 E Chatham St in downtown Cary. Email Chuck to let him know you’re coming.

Most of us buy tubes the way we buy spark plugs. The 19 inch and 21 inch sizes are not something you find at a tire shop on a Saturday, so when a good source has them you buy two or four, and then they sit. Sometimes they sit for a decade. It is worth knowing what actually harms a stored tube before that happens, because the answer is not what most of us assume.

One note before going further. This article is about butyl tubes, which is what nearly all of us have. Butyl is a synthetic rubber invented in 1937, its first major use was inner tubes, and it is still the standard tube material. Snyder's, for one, says its Model A tubes are 100 percent butyl. If you have a genuine old stock tube from the Model A era, or one you know to be natural rubber, the rules are stricter, and there is a section for you at the end.

The advice you hear most often is to store tubes lightly inflated, so that a limp tube does not crease where it folds. But for a butyl tube in a box, there is no need. Goodyear's instruction is to keep tubes in their original cartons whenever possible, and otherwise to dust them with talc and wrap them in heavy paper.

Butyl stores well. It holds air far better than natural rubber, and it stands up to ozone, sunlight, and heat much better too. But butyl is not invulnerable.

The first concern is creases. A tube folded hard, or hung over something narrow, takes a sharp bend, and over the years the rubber cracks along it. Goodyear's aircraft tire manual, which covers tube storage in more detail than any automotive source we found, is blunt about it: "Under no circumstances should tubes be hung over nails, pegs or any object that might form a crease in the tube. Such a crease will eventually produce a crack in the rubber." A crease does the most harm next to the valve stem, where the rubber is bonded to the metal and where tubes tend to fail anyway.

The second is oil. Butyl resists petroleum no better than natural rubber does; Parker rates both as poor. Gear lube, motor oil, grease, and gasoline all attack it, so keep tubes well away from the shelf where the lubricants live.

The third is heat. Rubber ages faster warm than cool, and the difference between a Carolina attic in August and an interior closet is large. Goodyear recommends storing tires and tubes between 32 and 85 degrees Fahrenheit, which rules out most attics and a lot of garages in summer. I suppose if you have a garage fridge, you could store them in there, but that would leave less room for critical beer supplies.

Ozone and light come last for butyl, but they still count. Butyl resists ozone well without being immune to it, and the standing advice from both Goodyear and the US Army is to keep all tires and tubes away from equipment that produces ozone: battery chargers, electric motors, welders, and generators. Keeping the tube in a box takes care of light.

Humidity, at the levels a house or garage sees, does not do much to a butyl tube. It does matter for the brass and steel around the valve stem, and it will turn a talc-dusted tube into a paste-dusted tube, but it is not what makes rubber crack. Ensure that all tubes are stored with valve caps on.

Do not hang tubes. Goodyear's warning about nails and pegs applies to any narrow support. I’ve seen it recommended that tubes be stored inflated, on a dowel with a pool noodle wrapped around it. The main problem with this advice is that, over time, your tubes will go flat, and if you go a month or two without topping them up, the tube will start to crease at the top and bottom. The other problem with this advice is that many of us don’t have room in a climate-controlled space to hang tubes like this, so you would be exposing the tube to excess heat for minimal benefit.

Dust the tube with talc, or a talc-based tire powder, before it goes into storage, as Goodyear recommends. It keeps the rubber from sticking to itself where it touches, and it makes the tube much easier to work into a tire when the day comes. Cornstarch baby powder is a common substitute and works, though it is worth keeping dry. Do not use anything petroleum based.

Unfold it, inflate it enough to hold its shape, and look at it in good light. You are looking for fine surface crazing, for any hardness or loss of stretch compared with a new tube, and above all for cracking around the base of the valve stem, which is where age shows first. Run your fingers over the whole tube. Rubber that has gone off feels different, and you will know it.

Think twice about reusing a tube that has already been in service. Tubes stretch in use, and Goodyear recommends against reusing aircraft tubes at all, noting that they "can grow as much as 25% in service." A grown tube can fold over on itself inside the tire, and a fold in a running tire can pinch and fail.

Use the oldest tubes first. Goodyear and the Army both call for first-in, first-out rotation of tire stock, and the rule applies to a shelf of four tubes as well as to a warehouse.

Natural rubber is far more vulnerable to ozone, and for these tubes ozone becomes the main threat. Ozone breaks the carbon to carbon double bonds in the rubber molecule. Natural rubber has one in every unit of its chain, while butyl has very few, which is why butyl resists ozone so much better.

The useful fact here is that ozone cracks form only in rubber that is stretched. Below a small threshold of strain, rubber exposed to ozone develops a thin hardened surface but does not crack. A 2022 laboratory study showed this directly: natural rubber samples held in ozone with no load did not crack, while identical samples stretched 20 percent did. The threshold is small, so the stretch along the outside of a tight fold, or an inflated tube, can be enough.

So store a natural rubber tube with no air in it. The US Army gave the same instruction in 1942, before butyl tubes were in general use: tubes not in their packages "should be deflated and folded, then covered to protect them from air, moisture, grease, and oil". Fold it loosely, since a sharp fold stretches the rubber along its outer edge, and seal it in an opaque bag to limit how much air reaches it. Distance from the battery charger matters more for this tube than for any butyl one. When you inspect it before mounting, the fine crazing described above is what to look for, and a natural rubber tube that shows cracks should be retired.

Neil Kaminar, expert mechanic and prolific online commenter, is offering to let club members borrow his wheel balancing adapter. This allows a Model A wire wheel and tire to be dynamically balanced on a modern balancer machine, which you should be able to find at your neighborhood auto shop.

Opinions are mixed as to whether balancing helps with Model As. Many original wheels are too badly bent to be properly balanced, and many cars aren’t driven fast enough or far enough to notice the difference. However, if you’re building a daily driver or prepping for touring, it certainly can’t hurt.

Neil’s shop is up near Wilkesboro, so if you plan to get your wheels balanced, you might consider simply taking the wheels up with you and having them balanced at an outlet near his house, thus saving the return trip. Email Neil to make arrangements.

Rebuilding a Model A generator usually comes down to the commutator, the ring of copper bars the brushes ride against. Years of service leave it worn, grooved, or out of round, and the proper fix is to turn it true on a lathe and then undercut the mica insulation between the bars so it sits just below the copper. That is exactly what an armature lathe is built for, and it is not the sort of tool most of us keep on the bench.

Tad Petrie, a skilled Model A mechanic in Kenly, has one and has offered to lend it. The lathe was a gift from his father, and Tad would rather see it put to work than sit idle. Any member who wants to recondition a generator is welcome to borrow it.

Tad also has a growler to go with it, and that pairing is what makes his bench so useful. A growler tests an armature for the faults a lathe cannot fix. You set the armature in the growler's V-shaped cradle, switch it on, and hold a thin steel strip, an old hacksaw blade works, over each slot as you rotate the armature. Over a shorted winding the blade buzzes and dances, the "growl" the tool is named for. With a test lamp the same setup will find windings that are grounded to the shaft or open. Turn and undercut the commutator on the lathe, confirm the windings are sound on the growler, and you have checked the whole armature before it goes back together. The growler works for starter armatures as well as generators.

Email Tad to make arrangements.

Here is one to watch for anyone who wishes their Model A pulled a little longer between shifts. Classic Cars Frohburg, a Model A parts house in Germany, has manufactured a limited run of a replacement main shaft and cluster gear set for the stock Model A transmission. The new gear set makes first and second gear "taller," lowering those ratios so each gear carries the car further up the speed range before you shift. The payoff is mostly in second, which loses less engine speed on the shift up to third. Top speed is unchanged, and the stock case, shift tower, and clutch all stay put.

That makes it an interesting middle path between living with the stock gearbox and the bigger surgery of a Mitchell overdrive or a full transmission swap: original appearance, original driving ritual, just better-spaced ratios. The set is made in Germany and sells for $2,100, with a demonstration of the design and a back-to-back driving comparison in the maker's two YouTube videos.

The catch, for now, is that the shop ships only within the EU and the UK, so there is no straightforward way to land a set in North Carolina yet. Keep an eye on it. If the product succeeds, a US vendor may well pick it up, and it would be worth a look before committing to a more complex transmission modification.

Model A legend Ken Ehrenhofer is taking orders now for the front, jump, and third seat backs for the ‘29-’31 wagon body style. Writes Ken, “I asked people if they needed any and started to take orders. Well, this past week we started to deliver 7 of them, with at least 4 more to go as soon as they are finished. Very soon we will be doing the jump seat backs, as we have a orders for 16 of them right now, and then we will do the third seat brackets. We are planning on doing the wood for all the seats if you need that. If you need the legs, contact Jeff Yeagle as he is reproducing those.” You can email Ken to place an order or call him at 630-697-3906.

Jerry Bingaman, a PA-based rebuilder of carbs and distributors, announced recently that he is fabricating new Model A toolboxes that mount between the front bumper brackets. This toolbox design was available for a number of years but has been hard to find recently. Mr. Bingaman posted the following price list:

He says these prices will hold until his current supply of sheet metal runs out.

All boxes come equipped with internal weather-stripping and a lockset. Shipping costs are extra and include insurance. Payment is by check or money order; a 50% deposit is required to place an order. Get your orders in now before they’re gone (again).

Have you bought a distributor cam lately? If you look closely, you may notice that the cam you buy is not the original-style cam, but rather the style designed for the Model B in 1932. Bert's says their cam is "ground to B Specs to give a longer duration." Mike's says the B cam gives a "hotter spark, longer plug life." These accolades got me wondering: are they true?

If the B cam is so much better, why didn't Ford use that profile on the Model A? The design was within their capabilities to make. To find out the truth, I reached out to Mike Keating, an engineer and race engine builder for many years. Here's what Mike told me:

The Model A Restorers Club has opened a digital archive to its members: a searchable library covering every past issue of Model A News, the first thirteen editions of Technically Speaking, and the last thirty-one issues of John LaVoy's Model A Times, with the first thirty-three of those promised soon.

The archive appears to work by searching two repositories:

In my experience searching other publications this way, this will not be a silver bullet for finding what you want. The problem is that these magazines cover the same topics over and over again, so keyword searches tend to pick up dozens of hits that you still need to sift through manually. However, being able to access the articles online is a big improvement over the old method of first looking through the index and then pulling the magazine off the shelf to find it.

If you have a MARC membership, check it out.

Want another look at this year’s event? Click here to watch the video.

Every time we run an ad for S&J Parts, I call them up and ask whether there’s any new parts or sales they want us to feature. And every time they say no. Which means I need to trawl through their catalog looking for something unusual. Today’s find: a rebuild service for Zenith B carburetors.

For those who don’t know, the Model B Zenith carburetor provides greater airflow than the Model A Zenith and has a “Power Jet” design to increase fuel flow to the engine when accelerating. However, to benefit from these advances, you must use a bored-out intake manifold (sold by several vendors, or you can DIY it).

I don’t think any of the other major vendors rebuild B carbs. Mike’s will sell you a rebuilt B carb without a core for $650. The S&J rebuild service is half that price, so if you have a B carb core that (let’s be honest) you’re never going to get around to rebuilding, treat yourself and let S&J do it.

The following club member birthdays and anniversaries were accidentally omitted from our last issue. Happy birthday and happy anniversary!