Automotive Paints

This month’s question comes from Wendell Nobel:

Dave, I would love to read a little dissertation on automotive paints. I recall a day when GM cars were all painted with acrylic lacquer and Fords were acrylic enamel. Now we have polyurethane base coat with clear coat, single stage urethane and even some water based stuff. What is an antique car guy to make of it all? Should we use what was on the car when new or get up to date? Will environmental laws make the question moot?

Let me first briefly explain the history of automotive paints. The early autos were painted with the same paint people had been painting carriages with for years. There was no “automotive” paint. Not paint in the traditional sense we think of when we talk about paint today. Early paint was basically linseed oil and a binder, with pigment, or crude shellac. This paint was applied with a brush and took a long time to dry. These paints were not very durable, often literally falling off the metal in a year or two. These finishes offered very little U/V protection and broke down quickly.

The biggest challenge with producing the Model T Ford and other early cars was the time and space needed to paint cars. The parts were laid out on the floor and took days to dry. This bottle neck in the production was a huge problem.

Nitrocellulose Lacquer paint was developed to alleviate the time/space problem. Nitrocellulose Lacquer paint is made from the nitration of cellulose plants (boiling down plant fibers and mixing with nitric acid). This is also how celluloid film was made. The solvents evaporate from the paint, leaving a glossy durable paint finish. These paints need to be “rubbed out” to produce a shine. This paint does not “cure” and will return to a liquid state when solvents are applied. A popular early nitrocellulose lacquer paint was DuPont “Duco” paint.

Nitrocellulose Lacquer dominated the automotive paint market from the early 1920s well in to the 1950’s when it was displaced by Acrylic Lacquer, a synthetic polymer acrylic resin based lacquer. Acrylic Lacquer dried quickly, however, still needed to be buffed to a high gloss.

Enamel paints used enamel resins. This type of paint takes much longer to dry than lacquer and actually dries in two steps. First, the enamel reducer evaporates and the paint becomes solid. Next, the resin oxidizes when it reacts to the air. This is why the new finish cannot be waxed for 30 days after application. The enamel paints dry to a hard, glossy finish and do not need the rubbing out as lacquer needs. The drying of enamel paints could be accelerated by the use of a baking oven.

Enamel paints required the need for clean spray booths. The paint took so much longer to dry than lacquer paints; the finish was much more susceptible to damage from debris before it dried.

Lacquer and enamel paints were much more durable than the paint they replaced, but still offered minimal protection against U/V light and corrosion.

Lacquer and enamel paints are very unstable, and begin a color shift almost immediately. This fact makes them very hard to color match. People go to great lengths to match original colors. Unfortunately, the reality is the “original” color was so unstable there really is no true original color. Two cars painted the same color at the same time would not match each other after a few years time.

Today’s urethane paints offer much more protection than the lacquer and enamel paints they replaced. Urethane paint cures in three steps: evaporation of the reducer, oxidation of the resin and an irreversible chemical reaction between the resin and the isocyanate catalyst. Urethane paints began to be widely used in the late 1980s.

Base/clear paints offer even more protection. The color coat is completely buried under a protective clear coat. The clear coat provides the gloss in the paint.

Modern catalyzed urethane primers and paints offer a finish that can easily last the life of the car. I have found bare metal painted with epoxy primer and top coated with urethane paint offered very effective protection against corrosion.

So, what is an old car person to do?

Nitrocellulose Lacquer is almost impossible to find today. It also cracks easily, and will return to a liquid when exposed to solvents. Lacquer requires sanding and buffing to get a good gloss. Enamel paints are harder to paint, do not have stable color pigments, and oxidize quickly.

An authentic restoration would require the use of the original type of paint. Modern urethane paints do not have the same gloss and color hue; however, they are much more stable. Enamel paints are still available, although somewhat hard to get. Given the time and expense involved in a proper paint job, you have to consider the service life of the paint. Do you want to paint it again in 10 or 15 years?

Modern urethane paints are very forgiving to paint, and last a long time. Modern urethane finishes have a fantastic shine, and require minimal maintenance.

If you want to exactly duplicate an original car, you may want to consider a period correct paint. If you want the best shine, great corrosion protection and minimal maintenance you probably want a modern catalyzed urethane paint. I guess it is ultimately up to the user to decide which way to go.

Just to complicate things, there are new paints being used now which are replacing urethane paints. Waterborne paints are now on the market. Waterborne paints do not have the Volatile Organic Compound exposure of urethane paints. Use of waterborne paint, is being mandated slowly, due to environmental concerns.

Your Car Engine on an Oscilloscope

Guest mechanic this month started with an article from Ken Barber and finished by Wheel Tracks

0818 engine oscilloscopeWhen an oscilloscope is used by a mechanic to tune your engine, the picture to the left is what one good cylinder looks like during one firing cycle.

An oscilloscope allows you to see the voltage pattern of anything that uses voltage. They were first developed in 1932 and can be great for tuning your old car, even if your car is a 1901 vehicle.

The pattern to the left tells you how well your equipment is working, that produces the spark that explodes the fuel in your cylinders, that gives you car the power to drive down the road.

A…. Indicates the level of voltage the coil produces to make the spark at your plug. That little flat part just below and to the left of ’A’ is the moment your points close.

B…. Is called the “Spark Line” where if working properly as in this picture, should decrease in a smooth action to zero. The little wiggles to the right of ’B’ is the final remnants of the spark being absorbed by your condenser. When this does not happen, people radios and tvs get lots of interference, plus your engine can not be properly ready to begin its next firing cycle.

D… This show when the points close to allow voltage back to your coil and be ready to make the next 25,000 volt spark. That little oscillation between D and C is normal and show the voltage settling down while your coil initially starts it’s recharge.

The distance between D and E is called Dwell and is simply the time adjustment for your points to be closed allowing voltage to your coil.

The distance between A and E is simply a time period that one cylinder needs during one cycle. During that one cycle, four things happen.

  1. The gas and air mixture explodes from the spark at the plug.
  2. The exhaust is pushed out the exhaust pipe.
  3. The next mixture of gas and air is pulled into the cylinder.
  4. Then it is all compressed to be ready for the next big spark.

8 cylinder engine oscilloscopeThe picture on the left shows an 8 cylinder engine, all cylinders doing what they are supposed to be doing with the spark plugs firing with 14,000 volts. If a mechanic sees the 3rd vertical lines at, say, 5,000 volts, then he might pull the spark plug from #3 cylinder to see if it is defective.

If the little condenser oscillation is not there like we can see between B and D above, the mechanic can suspect a bad condenser.

On the right is a normal set-up for connecting a scope to your engine.

Scopes are inexpensive these days and you should not let yourself get duped into thinking this is complicated… it is not. The more you use it and the more you see the patterns, the easier it is to find problems and make your engine run as smooth as possible.

A scope can even be used in one-lungers, so hit Napas and ask some questions.

connecting oscilloscope to engine

 

Z Car Update

1972 datsun 240z wheel arch restorationAbsent any questions this month, I will give a brief Z car update. The car is a 1972 Datsun 240Z receiving a total restoration. The car had significant rust in the lower body panels and floor. The left side was much worse than the right side.

Work on the left quarter panel is progressing. The rusty inner wheel well was totally replaced. This involved drilling out the spot welds and removing the old panel. Fortunately, well made replacements are available. The new part was an exact fit. With the new inner wheel well in place, the repair of the outer quarter panel could proceed.

1972 datsun 240z wheel arch restorationWe obtained a Tabco rust repair panel. This panel is made of nice thick steel, but the fit is poor. I like to keep as much of the original car as possible. We went just above the rust, cutting the metal out, just above the rust area. We only cut out the rusty part of the quarter panel, and will weld in the replacement panel.

When fitting a weld repair, I do not like straight lines or sharp angles. I find it easier and stronger to have the weld seam a series of curved lines.

The repair panel was carefully trimmed to fit, and will be welded shortly. It will be spot welded along the wheel well, as original. I may also use two part panel epoxy, this will produce a much stronger, more weather tight bond than it had at the factory.

1972 datsun 240z

Editor’s notes….David and son, Sean, will have the Datsun 240Z at the Shelburne Show on Father’s Day weekend. A beauty of a car, as witnessed in the file picture to the left, is outstanding. Hiratsuka, Kanagawa in Japan is where they were built from 1970 to 1973. The 240Z was meant to compete head to head with the MGB-GT and won the race with its great de-sign and relatively low price.

Time is Money

My Chrysler minivan got a little rusty over the winter. This vehicle is too old to be worth much, but still practical and useful. It is a great vehicle to make the weekly dump run, go to Home Depot and to run errands with. It is also fantastic in the snow with the all-wheel drive system. With these duties, and with two teenage boys in the house it makes sense to keep it, and I can’t justify replacing it.

The lift gate is really too rusty to feasibly repair. A new lift gate is unjustifiably expensive. At the salvage yard I was told a decent used lift gate would be $275, and unless I got lucky and found a silver one, I would still have to paint it.

I found a van with a totally rust free lift gate, but it had a large dent in it. I asked how much they wanted for this one and was given a price of $50.

I had to buy paint to fix the rocker panels, one quarter panel and the front fender anyway. With a couple hours of work, the dent was removed and the lift gate is ready for paint. A couple hours of work saved me over $200.

Above,

Sounds Good – A Bright Idea

led headlightsOne of the headlights recently burned out on one of my Saabs. No big deal, this happens every so often. A set of premium brighter bulbs costs almost fifty bucks, and I have noticed they do not last as long as the regular bulbs. A pair of LED bulbs is only fifteen dollars more, and these will outlast the car. I decided to order the LED bulbs and try them. They are a direct fit replacement for the standard halogen bulb. Unlike many LED bulbs on the market, these bulbs are an engineered replacement for the incandescent bulbs.

On some vehicles, like my Chrysler minivan, the headlight needs to be removed to replace the bulb. This requires removing five bolts and takes time.

In addition to lasting much longer, the LED bulbs do not generate heat, takes far less energy, and you can actually touch the bulb without destroying the bulb. Interestingly, I noticed both old headlight bulb pigtails were partially melted when I installed the LED bulbs.

I will drive with these bulbs for a few weeks to make sure they work, at least, as well as the incandescent bulbs.

I bought these bulbs from superbrightleds.com. I am very impressed with their quality, selection service and price. They list replacement LED bulbs for virtually every bulb in the car.

Sounds Good

sounds goodI recently lost the radio in my every day Saab. I went to crutchfield.com to look at a replacement stereo. I wanted something inexpensive that would simply replace the radio in my car. I was surprised to see the many options and reasonable prices.

For less than 200 dollars, I can fit a replacement radio, with a CD/DVD player, Bluetooth, a video screen and a touchscreen. For a couple bucks more I can add a back up camera.

A unit with all of these features and GPS is roughly the same cost as a stand alone portable GPS unit. Of course, buying the unit from a place like Crutchfield includes plug and play wiring and all hardware needed to make the installation look factory original.

I am amazed at how many features these aftermarket stereos have, and at how much the cost has come down. Now, if I can figure out how to add side curtain air bags, collision avoidance and adaptive cruise control I would never need to buy a new car again.

EASY OIL SEAL INSTALLATION TOOL

easy oil installation toolAnyone who has replaced oil seals without removing the shaft that seals against the seal knows what a struggle the seal installation is. Think of replacing the front main crankshaft seal in place without removing the timing cover or the crank shaft. This job requires applying equal pressure around the circumference of the seal, or it will warp or bend.I have taken several pieces of scrap PVC Schedule 40 drain pipe and cut it in lengths of three inches or so. Interestingly, the diameter of many grease seals is the same diameter of PVC drain pipe. The thickness of the PVC pipe is the perfect thickness to use as an oil seal installation tool.

I have diameters of inch, inch and a half, two inches, two and a half inches, three inch, etc., sitting on my tool shelf, standing in the ready to use for seal installation.By placing the appropriate diameter pipe over the seal the seal can be easily tapped in to place with a mallet. For larger diameter seals, and pipe installation tools, I have a piece of 2 by 4 to place over the pipe before tapping with a hammer.

I Just Can’t Stop!

Let’s face it. Old cars have lousy brakes. Model T Fords only have brakes on the rear wheels, and even those do not work very well. To be fair, the Model T seldom goes over 30 miles an hour.

In the 1950’s and through the 1960’s, cars got bigger and much more powerful. As cars were getting heavier and faster, most still had single circuit drum brakes, many without power assist. Safety standards allowed single circuit brakes through the 1967 model year in the United States. If any brake line or hose ruptured, you had no brakes. If you have an older car with questionable brakes, and you enjoy driving it, you may want to consider upgrading the brakes.

lousy brakesThere are many aftermarket suppliers offering kits to upgrade brakes. Often, the parts were manufactured for later models of similar vehicles, and the parts easily bolt on earlier vehicles.

I believe if you actually drive and enjoy your car, simply upgrading to a dual circuit brake system is an important upgrade. This usually requires simply changing the master cylinder and adding a hard line or two. You may have to also add a proportioning valve. Often, this modification can also include adding power brakes by adding a vacuum booster servo.

Adding front disk brakes is another upgrade to consider. This can also be done after upgrading the master cylinder to a duel circuit system. Adding front disk brakes may involve changing the spindles. There are many kits available with all of the hardware needed for an out of the box bolt on installation.

I recently purchased a new, duel circuit master cylinder kit for the 1959 Corvette. This car is fun to drive, but just can’t stop. This kit is designed to also work with a front disk conversion kit, if I ever decide to go that route.

If you are considering improving the brakes on your car, check parts suppliers catalogues and on line forums to see what is available for improving your brakes.

Engine Management Upgrade

1987 saab 900The distributer in my 1987 Saab 900 Turbo recently broke. Even though it is a Bosch distributer, it is no longer manufactured and parts are not available. This distributer was only used on model years 1986 and 1987. I was able to find a used one; however, several people suggested I upgrade the engine to the later fuel in-jection and ignition system.

The fuel injection and engine management electronics on this car were state of the art, in 1987. Engine management technology improved significantly since.

Saab continued to use this same basic engine right up to the end, and the engine was updated to coil on plug ignition and an improved fuel injection/engine manage-ment system. By upgrading the engine, the engine performance was significantly improved, as was engine efficiency. I have been told to expect an extra 6 miles to the gallon, and an extra 40 horse power with the change to the later components. Another benefit is OBD 2 engine management. Diagnosis and repair of problems is easily handled with a universal OBD 2 code scanner, no more dependence on a Saab Tech II code scanner.

To make the change, I can either take the components off a newer Saab, or buy a conversion kit. The process involves removing the distributer, coil, electronic control module, and the various electrical components and installing the newer components with some extra sensors. Many cars from the 1960’s through the early 1990’s have engines that continued in production through the evolution of modern engine management. Upgrading these engines to modern engine management could be a fun project, with great rewards.

What does “FG” Mean?

Dave is taking a brake this month – An email exchange with our VAE expert on Vermont number plates.

fg series vt license plateVAE member, John Sandvil, recently purchased a Vermont number plate with # FG81. John bought it because it was different but did not know the reason for its odd number.

1950s vermont license plate prefixesTo the rescue….Gary Irish. This is part of his reply: Yes, I can tell you what it is, and will probably tell you more than you want to know! It is a plate for a state owned vehicle, and more particularly for the Fish & Game department. State vehicles were first issued special plates in 1922, and through 1925 had “STATE” written out on the bottom of the plate, similar to truck and repairer plates of that era. From 1926 to about 1950, they had an “ST” prefix, and at least from 1951, only an “S” prefix (I know 1948 had ST and 1951 had S, but don’t know about 1949 and 1950). This went through 1960, and in 1961, they issued permanent plates to state vehicles with a two letter prefix designating the department to which the vehicle was issued. These plates did not have a painted border, but somewhere around 1970, new plates were issued, essentially similar except these had a painted border. These were used until the mid-’80’s, when they transitioned over to the plates in use today. I’ve attached a few pictures to give you an idea of what they looked like. The F&G plate is probably similar to the one you are asking about. The similar one without the border is Forest & Parks. I also added a sheet that gives the meaning of the letters on the 1961 version. And by the way, the picture of the 1925 state plate may look a little odd – it is a replacement plate. These were used to replace lost plates, and were embossed with only the non-unique parts of the plate. The motor vehicle department, at that time housed in a house which once stood where the state office building is on State Street in Montpelier, had a supply of these, and when a request came in for a replacement plate, they took the appropriate blank (in this case STATE, (pictured left) but they also had them for passenger, truck, etc.) and hand painted the number on the plate in a workshop in the basement of the house and sent it out.

1925 vt license plateAfter answering your note about the license plate, I got to thinking that maybe you can answer a question for me, or at least you might know someone who can. I recently got a copy of a picture, which shows a man named Clinton Abbott in the middle of what is now Route 15 in front of the park in Underhill Flats. He was the Underhill station agent for the Burlington & Lamoille Railroad. The car has a 1911 dealer plate on it, and I was told by the person who gave me the picture that Mr. Abbott, at one time, was a dealer for Reo automobiles. From anything I can find online, this doesn’t look like a Reo, and I am wondering if you or someone might be able to tell me what make of car it is. From looking at pictures online, the closest thing seems to be a Maxwell, which has a similar shaped hood, but other details of any I could find didn’t look right, such as the cowl.

Wheel Tracks was unable to reproduce the picture that Gary Irish is referring to, but….does have a beautiful picture that can be emailed to you. There is a gentleman driving the car and two youngsters around age 10 as passengers. The Underhill church can be seen beyond the green. Please ask and I will email the photo to you. email…gafiske@gmail.com

It’s in the Bag

When doing engine work or restoration work, organization is key to success. I recently overhauled an engine in my shop, and I was greatly aided by a careful and thoughtful organization when I took the engine apart.

I carefully catalogued the nuts, bolts, hardware and parts in zip lock bags, carefully labeled with a sharpie marker. The valve cover bolts were placed in a sandwich sized bag, labeled valve cover bolts, Left. The head bolts and miscellaneous hardware were placed in quart sized bags and labeled. These bags were then placed, in a gallon sized bag, labeled and Left.

This method continued through the engine disassembly. The oil pump bolts were bagged, and placed in the bag with the oil pump. All of the bags of parts were placed in a box with all the other parts.

When I reassembled the engine, all of the nuts, bolts and miscellaneous hardware were easily located, and the order of opening and unbagging the parts, easily gave me what I needed without wasting time searching, and minimizing the risk of placing the wrong hardware in the wrong location. When installing the left cylinder head, I grabbed the bag labeled Left, and all of the hardware was clearly labeled. When I was done, all the hardware was accounted for. There was nothing missing, and nothing left over.

I also use this strategy when I take a car apart for major work or restoration. There is nothing more maddening than not being able to find a part when needed.

Zip Lock freezer bags have an extra strong zipper, and provide a white rectangle for labeling. The next time you are in the grocery store, I would suggest buying a few boxes of sandwich, quart and gallon sized zip lock freezer bags for your shop.