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Tech Tips 5



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Know you limitations   3/27/09

Each and every one of us has some things that we do very well and some that we would rather not talk about. It is just a fact of life. As I believe that you all know I am a big fan of the backyard builder and doing it yourself. I do feel that some projects are better left to the professional if you do not personally have the talent to properly perform the task. For me that talent is welding. Do not think for a moment that I will not touch a project involving welding. It is a case that I know my limitations and know when to ask for help. There is no fun in building a car and having a bad weld fail resulting in being stranded or worse yet causing loss of control and a crash. I make all my own parts carefully drill and shape the brackets and then assemble them before tack welding them together with a body shop mig welder.  I now take the part or frame to a qualified welder who puts the parts together for good.  I save big money as the time to make and fit the parts has been done by me and I sleep nights knowing the welds will not fail. Talk with other car guys and you likely will find a qualified welder who you can barter with for his services or a guy who works part time at a reduced rate on special projects like yours.



How to radius the rear wheelwells of your 1955 Chevy or other Gasser

 ...and get the tire centered in the wheel well. Mar. 15/09 

The first thing to do is to make sure that you have the rear end of the car in its final location. This means that the springs have been rebuilt or replaced and the rear suspension is completed. Even if you are using the stock leaf springs now is your chance to move the rear end forward or backwards. Many 1930’s cars have (in my opinion) the rear end too far forward. By removing the U bolts from rear end you can drill a new locating hole in the spring pad about an inch forward of the original hole. Make sure that you drill the hole in the second pad in the same place. By placing the spring center bolt in the new holes you will have moved the rearend rearward by the amount you moved the holes.Now on to laying out the radius on the wheel well. Support the rear end on jack stands and remove the wheels. You will need a piece of flatbar about 30” long. Drill two holes in one end of the flatbar to bolt it to your brake drum using two of the studs. Bolt the flatbar to the wheel studs and bend an offset in the bar so that it will clear the fender as you rotate the axle. Drill a hole in the flatbar at the point where you want the radius to be. Rotating the flatbar by turning the brake drum makes sure that the cutout is exactly centered around your tire. You can use this method to mark the fender or you can mount a rotary grinder to the flatbar to perform the cut for you.




4 bar  vs.. 4 link rear Suspension Feb 3/09

The topic of 4 bar vs. 4 link is one that comes up almost weekly. A lot of people think that a 4 Bar setup is the same as a 4 Link and by definition they are correct. They both are a method of locating the rear end of a car by using four pieces of pipe as the locating means. This is where the similarity ends.  I use the terms “Street” and “Drag race” to describe the applications for which each type is best suited. Drag race 4 link use spherical rod ends (high maintenance & noisy) while the street 4 bar use polyurethane bushings. Drag race 4 link bars are extremely adjustable while the street 4 bar angle is normally not adjustable and the bars are mounted parallel to each other. The drag race 4 link bars form an open ended triangle to permit you to change what is called the cars "instant center" (theoretical point that the tires push) to get the best possible traction.  The Drag race 4 link requires major frame modifications to install while the street 4 bar only requires a couple of mounting brackets be added. Drag Race 4 link is much more expensive than the street 4 bar even if the cost of the required frame modifications are not considered. Quality rod ends required for the 4 link cost many times more than the polyurethane bushings of the 4 bar and have a short service life. My recommendation is to use a  Drag race 4 link on a car only if it will see drag strip use and you expect to be turning times faster than 9.9 seconds in the quarter.  If you are building a street car stick with the street 4 Bar setup. The ease of installation, reduced maintenance and improved ride and handling make the 4 bar the correct selection for street driven cars. For street / strip cars ladder bars are often a very good solution. They are easy to install and tune and provide a reasonable ride and handling for cars that will see some track time and are expected to run 10 seconds or slower in the quarter.



Tips for Handling Telemarketers
Three Little Words That Work!!
'Hold On, Please...'
Saying this, while putting down your phone and walking off (instead of hanging-up immediately) would make each telemarketing call so much more time-consuming that boiler room sales would grind to a halt.  Then when you eventually hear the phone company's 'beep-beep-beep' tone, you know it's time to go back and hang up your handset, which has efficiently completed its task.
These three little words will help eliminate telephone soliciting.



Pinion Angle

Pinion angle simply refers to the angle of the differential’s pinion in relation to the driveshaft. The goal is to create a straight line from the back of the crankshaft through the transmission, driveshaft, and the pinion of the differential—under load. Due to the tendency of the pinion to rise under load, some angle must be present at rest. How well the rear suspension controls the position of the rearend is the most critical issue that determines how much pinion angle will be needed. Some types of rear suspensions offer more control than others and require different angles. A ladder-bar suspension normally requires ½ degree of pinion angle, a four-link requires 1-2½ degrees, and a leaf-spring suspension requires up to 6 to 7 degrees. In all examples, we’re talking about negative pinion angle, i.e., the pinion is nose-down in relation to the driveshaft. A straight driveline delivers the most power to the rear wheels. Always strive for 2 degrees of pinion angle on a street car regardless of the type of rear suspension being used.



 Setting Pinion Angle

Sometimes corrections need to be made at the front of the vehicle to ensure that the engine and trans are sitting in the proper location. The average car builder should strive for between 1 and 3 degrees between the tailshaft of the transmission and driveshaft, and 1 to 3 degrees between the driveshaft and pinion. Furthermore, the two angles should be nearly equal (between 1 and 3 degrees), but always opposite. On four-link–equipped automobiles, adjustable upper control arms are required to change the pinion angle (although in some cases, mild adjustments can be made by shimming the transmission mount). In the case of a leaf spring–equipped car, pinion angle is changed with angled wedges (shims) that are placed between the leaf spring and the shock-absorber mount (see photo). These wedges effectively rotate the differential forward or backwards depending on which way the wedge is facing


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