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Velocity Stacks — For Looks, For Power, or Both?

September 26, 2010 | Troubleshooting & Repair | 0 Comments
By John Wilhoit We tested 6" vs. 2.25" velocity stacks mounted to Weber 44IDF carbs on one of our 1925cc single plug engines. There was a change in the torque curve and (interestingly) no significant change in the fuel curve. There was an improvement of about 3 ftlbs in peak torque but a loss in the upper range. I determined the improvement to be insignificant when considering the weird look of such a tall air cleaner. Incidently, we've tested with and without air cleaners and have consistently seen no improvement by eliminating the K&N air cleaners; on the other hand, the Porsche factory mesh cleaners do have more restriction compared to the K&N, so eliminating them or switching to K&Ns will bring an improvement in horsepower. Using a filtering screen over the top of velocity stacks instead of an air cleaner will seriously affect the flow and should be avoided. (Click here to view a larger image of the curves shown below) Reprinted by permission of Wil...

Developing the Flow in Zenith Carburetors

September 26, 2010 | Troubleshooting & Repair | 4 Comments
Text and photos by Gary Koehler [Editor] As Gary points out, while significant flow rate gains were achieved as the result of the extensive modifications he made to the Zenith 32NDIX carburetor, he has not yet done dyno testing of an engine with his modified carburetors and compared the results to the same engine with stock carburetors, so potential HP increases have not been measured. Also, he carefully notes that "Flow rate gains do not guarantee HP gains unless all other elements in the system are designed accordingly." I have finished the rebuild and modify phase of the Zenith carburetors for my big bore rebuild, realized some nice flow and velocity gains, and wanted to share what I did with Registry members who are interested. While I don't claim to be a carburetor expert, and with due respect to those who have done carburetor, flow bench and dyno testing, I could find no published flow data or guidance for modified Zeniths, so I decided to flow test the modifica...

Transmission Oil

September 26, 2010 | Troubleshooting & Repair | 0 Comments
 By Pat Tobin, John Jenkins, Harry Pellow. Question by Joe Babin   Q: After reading thru the tech page on gear oils at Redline's website, I'm trying to decide which one of their products to use. My transaxle is original with 115,000 miles on it. No problems, no leaks, shifts well and I want to keep it that way for as long as possible. Any suggestions? Other manufacturers that have superior gear oil? A: It is questionable whether any synthetic gear oil is best for manual transmissions--it may be too slick to allow the synchros to get a grip. There have been conflicting reports about this on the [356Talk] list - some say that a synthetic (not necessarily Red Line) works fine, others say no. In some of Red Line's lit I once saw a mention of some sort of friction modifier intended to allow use in manual transmissions. But the last time I read the bottle of Red Line gear oil, right on the bottle there was a caution ab...

Porsche 356 Transaxle Upgrades

September 26, 2010 | Troubleshooting & Repair | 2 Comments
Tunnel Case (Types 644,716,741) By Mike Robbins The factory did not always make revisions at the serial number specified in technical literature. Some of these upgrades are very beneficial; others are of lesser importance. The following table is a work in progress. If you have comments and/or additions, please email Barry Lee Brisco, Website Technical Editor, at barry.brisco@356registry.com . Abbreviations used: SB = Service Bulletin; SMS = Shop Manual Supplement; PC = Parts Catalog.   Beginning Serial # Up To Serial # Upgrade Documentation 11001 14053 Change from steel to bronze shift forks SB 14/57 11001 ? (644) Add cups for front mounts. Revise quantity and positioning of reinforcing plates. SB ? 11001 15960 Revised operating sleeve: lead angle changed. SB 31/57 11001 16744 Change intermediate plate & clamp plate: 4 bolt to 5 bolt. SB 27/57 11001 22425 Change to flanged axle nuts. - 11001 22996 Chang...

Clutch Alignment

September 26, 2010 | Troubleshooting & Repair | 0 Comments
Text and photo by Ab Tiedemann I have taken the clutch alignment task one step beyond the shortened input main shaft tool that some use. Below is a picture of my set-up which shows the extra two aids used to center a Kennedy pressure plate and the main shaft for the disc when installing the clutch cover on a 200 mm assembly. The "extra aids" are fashioned similar to the 911 tool, but have the interface for the 356. These aids are in production. Look for an announcement on 356Talk when they are ready. There is no "Factory tool" listed for this procedure. It is one of common sense or at least one that has logic for the mechanically apt. When the 911 was introduced, the clutch plate was initially centered with removable loose pins [referred to in the 911 Worshop Manual as "dowels"]. See illustration III.245 of Section 52E in the 911 Workshop Manual. [Click here for a PDF scan of that page in the manual] The Factory tool number for this task sequence is unknown to m...

Gearing Graphs

September 26, 2010 | Troubleshooting & Repair | 0 Comments
By Larry Coreth Download an Excel spreadsheet file to calculate and graph all possible gear combinations per the Spec Book (requires MS Excel or a spreadsheet program that can read .xls files). Scroll down this page to see charts for gearing in various 356 models. Graph showing all standard gears at once. Download printable PDF file of this graph. Graph showing standard Coupe gears. Download printable PDF file of this graph. Graph showing standard C Coupe and Roadster gears. Download printable PDF file of this graph. Graph showing standard Speedster gears. Download printable PDF file of this graph.

Tool Number One: Garage Lifts

September 26, 2010 | Troubleshooting & Repair | 0 Comments
By Gordon Maltby Reprinted from the 356 Registry magazine If you could name a single tool that would consistently make your garage life easier, it may well be a hydraulic lift. Under-the-car work is so much easier if you're not on your back, and a bonus feature is the ability to stack cars for optimum use of storage space. Assuming you're willing to adapt your garage to accomodate one and willing to spend the money, the only question remaining is, "Which lift?" Two or four posts Although there are scissors and hinge lifts, single post and in-ground hydraulic lifts available, we're going to focus on the two types most commonly used by a home hobbyist: two-post and four-post, above-ground lifts. Prices for these begin at around $1500 US. The same type of lift from another manufacturer could cost over twice that, however. As with many other products, the design, materials, construction and a myriad of related considerations determine the price of any one brand's produc...

Garage Lifts

September 26, 2010 | Troubleshooting & Repair | 0 Comments
By John Audette, Ken Daugherty, Rick Dill, Ned Hamlin, Lloyd D. Keigwin, David Jones, Dick Weiss, David Winstead John Audette: There's lot to research to do when thinking of installing a garage lift for your 356. TYPES Scissors Lift: For working on a car, not for storage. Single Post Side Lift: Primarily for stacking one car above another. Bend Pak makes a good looking one that the various auto enthusiasts boards online seem to like. Two Post List, Symmetric & Asymmetric: Two post lifts use arms for lifting, as opposed to drive-on ramps. There is more load on each post then with a four post lift and it's recommended that the concrete floor it's mounted on is at least 6" thick to support the load, or that steel plates are used to distribute the load. Ones with connector across the top typically need 12' of clearance: you can put connectors across the bottom but then need to drive over them. Pro's: — The arms free the wheels which facilitates working on the car. —...

Travel Kit List

September 26, 2010 | Safety & Driving | 2 Comments
By Lawrence Wilkinson This spares/tools list might be a bit over-the-top depending on what you're planning to do. The toolkit doesn't include the obvious spanners [wrenches], sockets, etc. Parts Complete distributor, with clamp, timed and ready to go (or points, condenser, rotor, cap) 2 generator bearings and brushes Generator pulley, hub, nut, shims, 2 woodruff keys, and 2 fan belts 1 inner and outer front wheel bearing and grease seal Several spark plugs and a couple of wires (or at least the longest one) + connectors Spare coil + coil lead Voltage regulator Fuel pump (and socket wrench to remove it) or fuel pump diaphragm [consider an electric fuel pump as a spare Fuel filter Some throttle linkage pieces Anti-vibration rubber connection in the throttle linkage (T6) Spare clutch cable with related nuts & fittings Fuses and bulbs Exhaust valve + spring + keepers Valve cover gaskets (2) Valve adjusting screw Sump gasket Oil drain plug Oil filter gasket ...

Building & Using 356 Support Boxes

September 26, 2010 | Troubleshooting & Repair | 0 Comments
By Rink Reinking Introduction I have found it useful to have four "boxes" to support my car while working under it performing various suspension measurements and maintenance work. I decided to construct them from ordinary 2x6 lumber and plywood. Here are detailed instructions for making these boxes. Constructing 356 Support Boxes Click here for diagrams (Requires Adobe Acrobat Reader> Cut 1/2" plywood* (or strandboard* or waffleboard*) into 4 pieces each 12" by 24". Cut 2x6 lumber into 8 pieces, each 24" long. Cut 2x6 lumber into 12 pieces, each 9" long. Obtain screws, construction adhesive and paint if desired. A power screwdriver with a cross-point bit is very useful. A coarse wood file, power sander or sanding drum mounted on a drill motor can help make finishing easier. Place two long and three short pieces of the cut 2x6 in the arrangement shown in the diagram. Hold together with bungie cord or clamps...