By Butch Chaffer, with thanks to HMM’s Ray Bohacz for excerpts & ideas
I, as do most of us, do expect those who swing wrenches for a living to execute proper mechanical procedure and exhibit a level of basic automotive knowledge. And the same standard should apply to an enthusiast who works on his own car. The following is a list of major peeves (or big no-no’s) that have been noted over time while observing work by professionals and enthusiasts alike.

DIRTY CARBURETOR: When not clean and varnish-free, air bleeds, emulsion tubes and passages do not function as designed, and performance and engine drivability suffer. A gummy, dirty carb is commonly seen on beautifully detailed muscle cars that are driven. The pros aren’t immune either, as many times I’ve seen mechanics replace air filters and ignore the filthy carburetor underneath. Carb cleaner is still cheap and easy to use.

HANGING BRAKE CALIPER: Any mechanic worth his salt recognizes that a brake caliper is not meant to swing from a rubber brake line during repairs.  Use a wire, or rope, or bungee; anything to keep the strain off the hose. OK, some of you say “B.S., I’ve always done that with no problem”. Of course, the weakened crimp or slight hose stretch is never thought of when the hose fails a year later on a panic stop (musta’ been a rock or bad hose). But hey, you saved 2 minutes on the job.

HOISTING ENGINES: There are chains, straps, and steel cables meant to connect your prize to your hoist. OK, this is aimed mostly at the enthusiast, as most mechanics don’t want the liability. But using clothesline, fan belts, or romex house wire (yep, seen them all) to support a suspended engine really borders on gross stupidity. The obvious damage to the engine and/or vehicle when it breaks, and it will, is only surpassed by the potential injury to yourself or buddy (should one still be in the area). ‘Nuff said on that!!

WHEEL BEARINGS: Proper care is needed for long life of front wheel bearings; correct lubricant, adjusted to a specified pre-load, and kept in a clean environment when removed for brake service. Contamination by placing it on an old rag, inside a wheel cover, or around a dirty work area is a sure way to entice a future roadside replacement session, or worse. Wrap in a clean paper towel or virgin rag until ready for greasing and replacement.

TIMING LIGHTS: Unless you are working on a 1920’s, 30’s, or 40’s stocker, you have pretty much moved past mediocre ignition requirements on your ride. Modern automotive engines are amazingly efficient and powerful for their size. This is due in no small part to the precise spark control designed into these power plants. Long gone are the days of “timing by ear” for the best performance and drivability of your vehicle. Unless, of course, your expectations from that nice engine you installed is just “pretty close, good enough”. A decent timing light with a ‘dial-back’ feature is not expensive, is easy to use, and should be a part of every enthusiast’s tool box. Poor timing, even if not readily noticeable in your everyday driving, affects your exhaust emissions, gas mileage, plug life, oil life and even engine temp. Every decent mechanic and performance tech uses a timing light. It separates the winners from the losers. Even the experts aren’t that good at guessing.

DISTRIBUTOR CAM LUBE: Nothing wrong with that original classic that still uses points. In limited use of a few hundred miles a year they work fine. But a little maintenance knowledge is needed, especially for those who grew up with electronic ignitions and now have a classic with old school breaker points. The breaker arm on these points have, or should have, a felt pad that wipes the rotor cam ahead of the rubbing block. This pad contains lube that keeps the wear on the rubbing block to a minimum. Often this pad is missing or dry. It should be lightly coated with that grease in the little capsule that came with the points, as well as a thin film on the cam lobes, a must if the points have no pad. Point gap affects the timing and coil saturation, so maintaining proper gap over time is essential. The rubbing block can be worn away in a few hundred miles without proper lubrication. Lost that capsule? Auto stores such as NAPA have small tubes of distributor cam lube….a lifetime supply. Emergency alternative? Try a drop of engine oil off the dipstick onto your finger to apply a thin film in the cam lobe.

HAPPY MOTORING…..BE SAFE…..WORK SMART……HAVE FUN

Classic Cars and Modern Engine Oils – Myths & Facts

I’m sure you have heard the talk, seen some e-mails and read some articles or blogs about current engine oils and it’s use in your classic or pre-80’s vehicle. If not, it goes like this………..

ZDDP (zinc dialkyl dithio phosphate, which contains phosphorous, plus some zinc & manganese) has been reduced to levels in modern engine oils that will cause rapid premature wear, even failure, of flat-tappet camshafts. This also affects some distributor gears and non-roller cam chains. ZDDP, more commonly called ZDP (zinc dithiophosphate) by automotive engineers, has been used in engine oils for over 60 years; the main purpose being an anti-wear, anti-friction barrier between the lifter crown and the camshaft lobe. The phosphorous is poison to catalytic converters, so the new “Starburst/ API SM” engine oils have the ZDP levels reduced to eliminate early catalytic failure, which is “certain death” to non-roller cam motors. Use of ZDP additives or diesel engine oils, which have several times more ZDP and are perfectly compatible with non-emission controlled engines, are necessary for these older motors to survive. Running with the low ZDP levels in modern “starburst” oils is almost like running without oil in your beloved classic!!!

OK, boys and girls. Let’s put this BS where it belongs…..in your trash bin. Here is some sound engineering information from Bob Olree of the GM Powertrain Fuels and Lubricants Group, starting with a little history of ZDP use.

Read the rest of this entry »

Hi there, a little info on powder coating,

One of our generous sponsors for the Classics in Paradise Car Show is a local powder coating shop . So I thought some information on the powder coating process, advantages and disadvantages might be of interest.

What is powder coating?

Powder coating is by far the youngest of the surface finishing techniques in common use today. It was first used in Australia about 1967.

Powder coating is the technique of applying dry paint to a part. The final cured coating is the same as a 2-pack wet paint. In normal wet painting such as house paints, the solids are in suspension in a liquid carrier, which must evaporate before the solid paint coating is produced.

In powder coating, the powdered paint may be applied by either of two techniques.

• The item is lowered into a fluidised bed of the powder, which may or may not be electrostatically charged, or
• The powdered paint is electrostatically charged and sprayed onto the part.

The part is then placed in an oven and the powder particles melt and coalesce to form a continuous film.

There are two main types of powder available to the surface finisher:

• Thermoplastic powders that will remelt when heated, and
• Thermosetting powders that will not remelt upon reheating. During the curing process (in the oven) a chemical cross-linking reaction is triggered at the curing temperature and it is this chemical reaction which gives the powder coating many of its desirable properties.

General Description

Powder coating uses 100% resin in a dry, powdered form (MnTAP, p. 4). Powder coating works on the principle that opposite charges attract. The powder is pneumatically fed from a reservoir through a spray gun where the powder gains a low amperage, high-voltage positive charge. Parts to be painted are electrically grounded so that the positively charged powder particles are strongly attracted to the parts’ surfaces. The powder-coated part is then pulled through an oven where the powder melts and fuses into a smooth coating (IHWRICe). Substrates must generally be able to withstand temperatures of 260°F or higher (EPAd, p. 33).

Advantages and Disadvantages

Powder-coating materials can provide a high-quality, durable, corrosion-resistant coating. Powder coatings do not produce hazardous overspray wastes or wastewater sludges, and most do not release VOCs when cured (some powder coatings will release VOCs, such as caprolactam, a former HAP). With powder coating, users can collect the powder overspray and reuse it, resulting in transfer efficiencies of up to 99% (MnTAP, p. 4). However, powder coating systems require the complete conversion of a coating line, which can be costly. For more information on other advantages and disadvantages of powder coating, see table 23 at the end of this section.

Table 23. Advantages and Disadvantages of Powder Coatings (NCP2P, p. 3)

Types of Powder Coatings

Product manufacturers can specify the properties required in a finish (such as resistance to ultraviolet light, high durability, corrosion resistance and color) to a powder coating manufacturer who then formulates the appropriate powder (IHWRICe). Coating powders are frequently separated into decorative and functional grades; decorative grades generally have a finer particle size than functional grades. Powders are also divided between thermoset and thermoplastic resins (EPA, p. 163-164).

Thermoset resins crosslink to form a permanent film that withstands heat and cannot be remelted. They are used for decorative and protective coatings for architectural structures, on appliances and furniture, and elsewhere. Thermosetting resins are characterized by their excellent adhesion to metal; they are one-coat systems and do not require a primer (Farrell, p. 81). The five basic families of thermoset resins are epoxies, hybrids, urethane polyesters, acrylics and triglycidyl isocyanurate (TGIC) polyesters as described below:

• Epoxies are used for both functional and decorative coatings. Their functional properties include outstanding corrosion resistance and electrical insulation. Decorative epoxies offer attractive finishes that are flexible, tough, and have excellent corrosion resistance and high-impact strength. However, these coatings lack ultraviolet resistance and, therefore, are not recommended for outdoor use. In prolonged exposure to sunlight, they tend to chalk and discolor. Various types of hardeners are used with epoxy powder to optimize its properties.
• Epoxy polyester hybrid coatings are mainly used for decorative applications. They are more resistant to chalking and over-bake yellowing than pure epoxies, but have a lower surface hardness and are less resistant to solvents. They exhibit better transfer efficiency and a greater degree of penetration into recessed areas of a part than other resins.
• Urethane polyesters are formulated with polyester hydroxyl resin combined with blocked isocyanate hardeners. They exhibit outstanding thin film appearance and toughness as well as good weathering properties.
• Acrylic-urethane coatings are formulated with acrylic resins crosslinked with blocked isocyanates. They have excellent color, gloss, hardness, weatherability and chemical resistance, and have an excellent thin film appearance. However, they are less flexible than polyesters.
• TGIC polyesters contain a polyester resin crosslinked with TGIC as a curing agent. They offer very good mechanical properties, impact strength and weather resistance. They are resistant to chalking and are often used for outdoor parts, such as patio furniture, lawn mowers, as well as aluminum extrusions and panels for large commercial buildings. In Europe, reduced occupational-exposure limits were recommended for TGIC powders as a result of in vivo mutagenicity tests (EPAd, p. 28).

Thermoplastic resins form a coating, but do not undergo a change in molecular structure. These resins can be remelted after they have been applied. Thermoplastic powder coatings melt and flow when heat is applied, but retain the same chemical composition when they are cool and solidified (KSBEAP, p. 10). Although some thermoplastic materials provide adhesion to metal, most require a primer (Farrell, p. 81). Thermoplastic resins are mainly used in functional coatings, such as thick, protective coatings on dishwasher trays. Examples of thermoplastic resins used in powder coating are polyethylene, polypropylene, nylon, polyvinyl chloride (PVC), and thermoplastic polyester. These examples are described below:

• Polyethylene provides excellent chemical resistance and outstanding electrical insulation properties. These coatings are smooth, and have a medium gloss and good release properties that allow sticky materials to be cleaned from their surfaces. These are often used as coatings for laboratory equipment.
• Polypropylene produces a surface that is very inert and is often used in applications where the part that is powder coated might be exposed to chemicals.
• Nylon offers excellent abrasion, wear and impact resistance, and a low coefficient of friction. Nylon is commonly used as a mechanical coating for sliding and rotating bearing applications in appliances, farm equipment and textile machinery.
• PVC provides good durability as well as flexibility; dishwasher trays are an example of a product coated with PVC.
• Thermoplastic polyester offers good exterior durability and weatherability. The coating does not usually require a primer for good adhesion to most metals. These materials are often used on outdoor metal furniture (EPAd, p. 26 and PCI, p. 6-7).