Grinding Valves in Antique Cars (exotic cars)
No commentsBy Peter Salmonford
Owing to the fact that the inlet valve is not subjected to the temperatures which the exhaust valve reaches, it is very rarely necessary to grind it in. The period at which valve grinding becomes necessary varies with different engines and the care of driving, etc. Roughly, with a water-cooled engine, the exhaust valve should be ground in after 3,000 miles and the inlet after 6,000. No harm can be done by grinding in a valve, so that if an engine loses power before it has run this distance it is well to examine the valves and give them a slight grinding. After the valve is replaced the cotter should be readjusted, and locked by means of the nut.
If a valve is badly burnt examination will show whether it is better to fit a new valve rather than grind in the old one. Very often a badly burnt valve can be recut and trued, and to replace the whole process of valve grinding, a process of valve truing and an apparatus for carrying it out has been evolved by the Southern Automobiles, Ltd. The apparatus consists of a pair of cutters, one of which recuts the valve face after it has been removed, whilst the other has the same effect on the valve seating. Into the respective merits of the two processes it is not proposed to enter, but valve grinding is the more common practice, and it can be applied not only to the main engine valves, but to other valves when the need arises. Thus a petrol or water tap sometimes leaks slightly, when it should be removed and the removable part ground in with some fine emery powder.
It will have been gathered that grinding-in of valves is done to restore loss of compression, but this weakness is sometimes due to other causes. For instance, any one of the cylinder joints may be leaking. The sparking plug washer and that upon the valve cap which screws into the opening sometimes leak, and to ascertain if this is the case some paraffin should be squirted round these washers and the engine turned round just to come on to the compression stroke. When pulled slowly over the compression stroke the presence of bubbles will indicate if there is any leakage at these points. If there is leakage new washers must be used. On no account should any adhesive mixture, such as boiled oil or gold size, be put on the screw threads. This is sometimes done to obtain good compression, but it is inadvisable, on account of the extreme difficulty in separating the parts later.
Peter Salmonford is a keen fan of cars, and likes to write about antique and modern vehcles. Take a look at his other articles on hydrogen conversion, the benefits of an electric car kit and using browns gas in your own car.
Handling Wear and Tear in Antique Car Engines
By Peter Salmonford
Loss of compression is also due to wear set up between the piston and cylinder. In engines that have done a considerable amount of running the cylinders may have worn slightly oval, and they should be carefully examined to see if this is the case, and if so, should be rebored. The trouble is usually, however, confined to the piston rings, and new rings are generally required on a water-cooled engine after 10,000 to 20,000 miles.
In good engines carefully looked after perhaps they will not be necessary until 30,000 miles have been run. To fit new rings is, though not a difficult matter, one that requires a certain amount of care. It is very easy to put a ring into the top slot, but to get it into one of the middle ones is not so easy. To do so the adjacent grooves should be temporarily filled up with some packing or, what is better, some strips of sheet metal or whalebone should be employed and the ring slid over these until the proper groove is reached. These strips will prevent the ring from fouling the adjacent groove.
Each ring after being in use must be bright the whole way round ; if this is not the case it shows that contact is not made throughout the whole length of the ring, and a new ring should be fitted. Piston rings should fit comparatively tightly in the grooves, and when compressed so as to lie nearly flush with the piston the slots should be closed.
The weak point in piston rings, as regards holding compression, is the slot, as a slight leakage is bound to take place along it. Consequently when two or more rings are fitted the slots should be arranged alternately on opposite sides of the piston, so that as long a path as possible is made for the escaping gas and leakage reduced. Thus when the cylinders are removed care should be taken to turn the piston rings into this position. In some cases the piston rings are pegged to prevent their taking up wrong positions.
After a water-cooled engine has run a considerable distance, say anything from 5,000 to 10,000 miles, it may be found that power is falling off, in spite of the compression being good, that when going up a hill with the throttle wide open the engine knocks and does not seem to run so well as when new, or that the engine preignites or continues to run when switched off. These are definite signs that the inside of the cylinders and the piston heads require cleaning.
Peter Salmonford is a keen fan of cars, and likes to write about antique and modern vehcles. Take a look at his other articles on hydrogen conversion, the benefits of an electric car kit and using browns gas in your own car.
What Styles Of Car Lifts Are There To Choose From?
By Christine OKelly
Automotive lifts have been designed with a variety of uses in mind. Some car lifts are smaller and intended for smaller vehicles, making them ideal for small repairs and storage in home garages. Larger units designed for heavy-duty repairs have been created for professional garages and other applications where they are constantly in use. Here are a few models that you may be considering.
Post Model Car Lifts
Most commonly found in private shops, two-post automotive lifts deal with vehicles of several sizes and weights and only require a small amount of space. This version comes in two styles. An asymmetrical version has centered posts to provide access to the interior of the vehicle and is better for vehicles with heavier rear ends. Symmetrical two-post models stand opposite of each other and have stabilizer bars in the opposite direction. The vehicle’s weight is centered on the equipment.
Commonly found in showrooms and car shows, the four-post version is a better fit for heavy vehicles and storage. The additional posts on this style of lift add stability to the equipment. This style allows vehicles to be driven up onto it, which makes them very convenient to use in comparison to two-post styles.
Parallelogram Styles
Parallelogram or scissor automotive lifts are best known for their ability to make space under a vehicle in private workshops. They are also better suited for large framed vehicles like buses and delivery trucks. These benefits do come with a price, however. First, these models cost considerably more than four-post car lifts. They also require a large amount of space to use and are not recommended for storing vehicles.
Hydraulic Systems
This style is a favorite of many professional mechanics for the effort it takes out of the job. The hydraulics involves a series of liquids put under pressure by a set of pumps and cylinders. This version has increased security combined with the added convenience of use.
Most of these car lifts use a combination of electricity and hydraulics and are one of the most common lifts seen in auto shops because the power is used to run hydraulics. They are quick to raise and lower and have the power and stability needed for storage. Professional vehicle storage companies as well as mechanics use these systems on a constant basis.
In-Ground Styles And Mechanical Automotive Lists
Systems set in-ground are a favorite of big auto repair shops and other professionals who need space while working with these systems. Cars can stay on the lifts overnight if need be, and with the lift at ground level, it frees up as much space as possible. Commercial businesses also use these systems because they prevent having vehicles damaged due to of a lack of space. Unfortunately, this style of car lift also comes with a significant price tag to match.
Mechanical car lifts look very similar to the hydraulic style previously discussed minus the hydraulic systems. Instead of liquids, pumps, and cylinders, mechanical systems use screws, locks, bolts, and wrenches to suspend a vehicle. Because these units do not cost a whole lot more than hydraulic versions, these are a rare find in the automotive industry.
Auto Lifts For Specific Uses
Smaller shops that need to store more than one vehicle often utilize space saving automotive lifts. These will store one vehicle on the top and allow a second vehicle underneath with mere inches to spare. Since show floors and high-end car shows are all about looks, showcase lifts have a high aesthetic value. They are sturdy enough for storing vehicles, but have finishes and features that compliment the top end of the automotive market. Large commercial and showcasing units come in different styles to meet the needs of the event. Most commonly, these automotive lifts are seen at big auto dealers and professional car shows.
These are just some of the automotive lifts available to consumers. Certain versions have been designed specifically for storage while others were created with industrial work in mind. The smaller garages and automotive enthusiasts were not left out either. Car lifts have a variety of sizes, shapes, and mechanical actions to suit every purpose.
Christine O’Kelly writes for the automotive lifts manufacturer and distributor, SVI International. They carry a complete line of car lifts and lifts for heavy-duty equipment.
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Monday, September 29th, 2008 at 9:05 am and is filed under automotive. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.
