JAGazette Technical Editor

Normal lobe         zero clearance lobe

Borescopes On a related note, have you ever wished that you could look inside an engine without taking it apart? Sort of like doctors can do to you? Well, such a tool exists if you have the money. It won’t let you look inside while the motor is running like your doctor can, but it will do some pretty amazing things. This tool is known as a borescope, because it was originally designed to look down the bore of an engine through the spark plug hole. It’s based on fiber optics with a built-in light source, just like the scopes doctors use. With the proper attachments such as mirrors, fish-eye lenses and different eyepieces you can examine the valves, the timing chain, the cams, and the crankcase. You can even look under the dashboard for that elusive squeak or rattle. Cost? Basic scope about $1200. With all the bells and whistles, $4000.

Basic borescope

Planetary gears Sad to say that the last of our members who used a curved dash Olds for daily transportation left the club a few years ago so we can’t get any firsthand feedback on what it was like to operate a turn of the century planetary transmission, but many of use remember the Model T Ford and it’s planetary transmission operated by pedals. When Henry was forced to give up his brainchild in 1927 he also had to grudgingly go with the flow and use a conventional crashbox. Henry couldn’t understand why people wanted to go back to an inferior transmission, but that’s what the market demanded. Actually, planetary transmissions never left the automobile scene, as the Borg-Warner overdrive appeared in 1934 and the GM Hydramatic in 1939. Today, most transmissions are of the planetary type because most transmissions are automatic and virtually all automatic trans’ use planetary gears. Click here and you will get a view of a typical planetary gearset. This one happens to be from a GM Turbo 350, an ancient design. This gearset is able to reliably transmit 450 h.p. As you can see it’s only 6 inches in diameter. It weighs 8 lbs. The amazing thing is that it is capable of producing seven different gear ratios. Two of them are reverse, but since all transmissions have at least two gearsets, both reverse ratios are useable. In the past decade we have moved from transmissions with 3 forward ratios to ones with 5. Six speed automatics are just over the horizon. Why so many gears? Because torque converters are notoriously inefficient. Even with lockup clutches, variable pitch stators and all the latest tricks programmed into the PCM (power control module) converters waste 3 to 5 % of the engine’s power. We all know that the IC engine is a constant speed device. The more we can operate it in a very limited rpm range the better the fuel economy and the lower the emissions. So the future requires a transmission with lots of gear ratios. What about the CVT (continuously variable trans) you say? Well, it works fine for the Toyota Prius with its rip-roaring 70 h.p., but somewhere around 200 h.p. the CVT hits a greased wall. I love to make predictions, and I predict that we will see a true manu-matic in the near future. It will consist of a multi-plate clutch in front, replacing the torque converter completely, three to four planetary gearsets arranged in a series-parallel configuration behind the clutch and a rather elaborate electohydraulic arrangement of bands and multi-plate and one way clutches behind. For the enthusiast the front clutch will have nominal manual control with a pedal, i.e. you’ll be able to hold the pedal down, rev the engine and dump the clutch to induce wheelspin. Of course this will be computer controlled so you can’t waste the drivetrain completely and run the warranty costs out of sight, but it will return some of the fun to driving. For most driving you will let the computer make all the decisions, just like today’s automatics. There will be no loss of performance vs. a manual. Quite the contrary. Because of the multiplate design there will be much less clutch slip and planetary gearboxes have the beautiful feature that you can briefly engage two gear ratios at once, so shifts are truly instantaneous and there is no interruption of powerflow. Look for an 8 speed tranny behind the next generation XKR. You read it here first.

 More on access to late model tech info Last month I wrote about the difficulty individuals and independent repair shops have in getting the information necessary to work on late model cars, especially high end foreign cars like Jaguar. For your information it is the law that this information must be "readily available at a fair and reasonable price" if it in anyway effects the emissions performance of said vehicle. Since virtually everything on a car effects its emission performance the information should be available. This includes manuals, CD’s, DVD’s and even links to the factory database. If you’d like to read the entire regulation go to arbis.arb.ca.gov/msprog/obdprog/mo97_24.pdf . (There is an underscore between the 97 and the 24). It runs 45 pages, but the relevant text starts on page 36. Make a printout and show it to the dealer when you go in to buy your manuals.

The forthcoming F-Type As the day of the F-Type slowly approaches I can’t help but wonder. . . Ford has never delivered an affordable world class sportscar. Remember the 60’s as GM built the reputation of the Corvette as a true American sportscar and Ford teased us with countless show cars, but gave us the Thunderbird and the Mustang? If it hadn’t been for Carroll Shelby and his Cobras and GT 350’s Ford wouldn’t have even been a blip on the radar screen. The market is flooded today with affordable sportscars. Most miss the mark for one or several reasons. The Honda S2000 has limited appeal because of its size and ridiculously high-revving, no torque engine. The Toyota MR2 is too weird with its happy pig styling and poorly chosen gear ratios for American freeways. The BMW Z-3 is a fair package in its more powerful forms, but suffers from less than coherent styling and interior packaging, and so-so handling. The Porsche Boxster, which is a runaway best seller in my neighborhood, seems to be the most complete package, lacking only a decent headlight treatment and frontend profile to be a complete winner, assuming, of course, you are a fan of mid-engined cars and all their idiosyncrasies. Will the bean-counters at Ford give us the car we’ve been yearning for since the demise of the 6 cylinder E-Type? If they do it will be a first. Let’s start a letter and e-mail campaign to the powers that be at Ford and Jaguar. Production is at least 2 years away. Now is the time.

Vacuum leaks Many cases of rough and erratic running and poor performance can be traced to a vacuum leak. In the days of yore there were two vacuum hoses on a car, one for the vacuum advance and one for the windshield wipers. By the 1980’s some cars had 20 different vacuum hoses running over, under, around and "through" the engine. Increased engine heat played hell with these hoses. So did inexperienced mechanics who hooked them up wrong or left them disconnected. Even if all the hoses are in good shape and properly connected you can still have a vacuum leak in the internal circuits of a carburetor, a deteriorated vacuum advance diaphragm, a climate control, or extra air valve, and where an injector butts against the intake manifold or the manifold gasket itself. Spraying carburetor cleaner around all the possible connections and noting a rise in engine speed is one way to detect a vacuum leak. If you have variable venturi Stromberg carbs there’s a good chance that the rubber diaphragms have deteriorated from the new formula gasoline. Don’t neglect the crankcase ventilation system. Any leak on the way to the intake manifold will cause rough running and poor performance.