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Why Should I Care About Compression Ratio?

December 1, 2010 | Troubleshooting & Repair | 0 Comments
By Ron LaDow If you are not contemplating or in the midst of an engine rebuild, you probably don't care about compression ratio. If you are, there are certain facts which should figure in your thinking. Engine life is inversely related to engine RPM. The 'power' an engine makes is largely irrelevant to engine longevity. An engine that makes 100HP at 5,000 RPM, and limited to that speed, will far outlast an engine that makes 75HP at 6,000RPM, and regularly run to that speed. Loads increase linearly with power and geometrically with speed. Engine speeds above 5,000 RPM are where almost all horsepower is quoted since it’s easier to make big horsepower numbers there. It's just not easy to make them at the RPMs commonly used; those big numbers are swapped for power elsewhere in the engine speed range. It's also easy to make noise, and this is entirely too often confused with power. There are four ways of increasing power in the range between 2,000 and 5,000 RPM,...

356 C Shift Linkage Refurbishment

November 17, 2010 | Troubleshooting & Repair | 6 Comments
By Ron LaDowShifter action in a 356 will never equal a car with has the lever sticking right out of the transmission, but it should be crisp and accurate in its selections. If your shifter seems vague, there are plastic bushings in three locations subject to wear which can make a great deal of difference in feel and accuracy. They are not expensive, a standard wrench set pretty much covers the tools required, but you should devote a weekend to the project if you've never done it before.PartsCup Bushing - (1) - Stoddard's part # 911.424.139 (for B/C cars, original # was 695.424.110.00). This is a plastic cup at the base of the leverRing Bushing - (1) - 695.424.211.01 A plastic ring bushing just aft of the cup bushingCoupler Bushings - (2) - no separate part numbers; ask by name These are two plastic bushings in an aluminum coupling, similar to a u-joint mechanism, just forward of the transmission noseInner Boot - (1) - 695.424.922.00Outer Boot - (1) - 695.424.921.03Buy the bushings f...

Changing the Oil

September 28, 2010 | Troubleshooting & Repair | 0 Comments
 By Jerry Wells, photos by Barry Lee Brisco   I have two basic procedures: Easy, Change Oil Only The Full Monty Easy Recently I have been changing oil that is fairly warm, that is, full engine temperature then cooled for approximately 40-50 minutes. All you need is: a jack jack stands an oil draining reservoir (large plastic container from any FLAPS [friendly local auto part supplier]) 19mm socket and handle 4 1/2 quarts of new oil Proceed as follows: I like to put the rear on jack stands then raise the front with the jack so it's level for maximum oil drainage. Not sure how to safely jack up your car? Read how.   Position the oil draining resevoir under the engine and remove the 19mm bolt from the bottom of the engine case. Use care as this is a pipe thread and is easily stripped. The oil will drain into the resevoir for recycling at your local auto parts store.   Remove the lid of the oil filter container (save gaske...

Valve Adjustment

September 28, 2010 | Troubleshooting & Repair | 2 Comments
By Ron LaDow Precision Matters Adjusting Valves: The First Step in Tuning Up a 356 Because of the interaction of the various engine systems, a tune-up on a 356 (and other engines of similar vintage) must be done in a certain order: Set valve clearances Tune the ignition system Tune the carbs Each prior portion of the tune-up contributes to the later. At the later-stage tuning of the carbs, there is a certain 'circularity' to the adjustments, but you have to draw the line somewhere. Contributions here will cover most 356s from 1955 and some 912s. You should have at least the Owners Manual, or Elfrink's tome to identify some of the parts referenced. Except for the carburetor adjustments, no special tools are required. If you are performing a tune up for the first time, allow a weekend. Order the parts first; there are few things that discourage fiddling with old cars like having to wait a week for a miserable piece of cork...

Ignition Tuning Procedure

September 28, 2010 | Troubleshooting & Repair | 6 Comments
By Ron LaDow Precision Matters Copyright Ron LaDow, September, 2004   Parts Required spark plugs points rotor (and get a condenser just in case) distributor O-ring plug wires (possibly) distributor cap (possibly) What Any internal combusion (IC) engine needs ignition of the combustible mixture in a particular cylinder at the proper time within a very small margin of error. The ignition system on engines of our vintage are electro-mechanical systems. The 'electro' part tends to be very reliable; it's the mechanical part that needs the most attention. Wear on the various parts can cause very large margins of error. Order the parts first. As noted above, you'll need a set of plugs, points and a rotor. Condensers are commonly replaced at a tune up, but commonly don't need to be, ditto distributor caps. Maybe the rotor falls into this category; you choose. Plug wires are good for at least 50,000 miles, but if you are uncertain, it may be worth...

Tuning Zenith 32mm NDIX Carburetors

September 28, 2010 | Troubleshooting & Repair | 3 Comments
Text and photos by Ron LaDow, Precision Matters   INTRODUCTION With very few exceptions, Zeniths tolerate all sorts of strange jetting and adjustments and still work OK. They work far better than OK if you spend some time to tune and optimize them. To tune them, you'll need: A good tool set A synchronizing tool Some method of measuring the accelerator pump volume (more later) Gasket kits Base/manifold gaskets (if you want to remove them for work) 32NDIX carb data reference (factory or aftermarket manual) Buy three gasket kits for two carbs; when one washer goes missing, you won't need to wait until next weekend to complete the job, and spares will come in handy one day or another. For similar reasons, do not throw out any sealing/crush washers you remove while working on the carbs. For good reason, carb tuning is the last task in a standard tune-up. It is impossible to tune carburetors if any other portion of the engine is damaged or out of t...

Tuning Solex 40PII-4 Carburetors

September 28, 2010 | Troubleshooting & Repair | 0 Comments
By Harry Bieker     Introduction & Requirements Solex's are easy to adjust when compared to other Porsche induction systems. But they are much harder to adjust than American two barrel carburetors. It takes a certain feel. Before attempting to adjust the carbs, the following must be correct: the engine must have correct cam and ignition timing the valves must be adjusted properly the points, plugs, distributor cap and ignition wires should be in like new condition the distributor must be mechanical advance the compression difference between cylinders should not exceed 20 PSI an engine compartment fuel filter should be in place Definitions   Note: Red type denotes components most commonly used in adjusting carbs 1 - Retaining screw 2 - Passage where high speed mixture enters air stream 3 - Needle & seat (after market shown, original has a spring loaded ball end) 4 - Fuel inlet banjo bolt (hollow bolt) 5 - Cover 7 - Injection...

Weber 40s and The Magic Combination of Jets & Tubes

September 28, 2010 | Troubleshooting & Repair | 2 Comments
By Jeff Stevens   I have been messing with these carbs on my car for about 2 years now. I probably would have been happy if I were most other people, but being an engineer, I had to fool with them to get better results. I have tried many combinations of venturis (28 and 32), jets (115-145), idle jets (50-65) emulsion tubes (F11, F7, F3) and air correctors (165-225). My car is a 62 S90 with a 86A webcam (290 duration), Crane HI-6 ignition and pertronix ignit0r in an .050 dist. The following are some of my observations. Dump the F11 tubes. No matter how many times I went back to them or with the combinations I tried them with, the car always felt like the brakes were partially on. The F3's are identical to the F11's except the body diameter is smaller. I believe they are just not a good choice for the application. They also tended to shift the mixture very rich. The F7's are the way to go. As one other list member...

Fabricating Weber Fuel Lines

September 28, 2010 | Troubleshooting & Repair | 0 Comments
Text and photos by Ken Daugherty My method eliminates the floppy rubber hoses, ugly clamps and twist ties I often see with Weber carburetor installations. I use NAPA steel tubing, pn 813-1235 (5/16" x 60"), forming one piece to fit behind and up under the lip on the fan housing (photos #1, #2, #3 below). I braze it in place. Note how the ends are positioned so the rubber hose will follow neatly around to the carburetor fittings. If you don't want to braze the tube to the fan housing, you can fabricate clips, braze the clips to the tubing and then mount the clips to the fan housing with pop rivets. The photos below show the brazed crossover installation. Next I fabricate a new line from the fuel pump to the carburetor fitting (photo #4). On the driver side carburetor you will need to add an extra 'fuel inlet pipe' from Pierce Manifolds, pn 10525.023, phone (408) 842-6673 (photo #5). The fuel hose I use is the common cloth wrapped 356 hose available from our vendors ...

Full-Flow Oil Filtration and the 356 Lubrication System

September 27, 2010 | Troubleshooting & Repair | 0 Comments
By Ron LaDow First published 356 Registry Magazine, Vol. 28, No. 6 Available in PDF format at Clean oil helps engines live a long and enjoyable (for us) life. Most all of us want our engines to last as long as possible. As pointed out in the article Stock Oil Filtration Effectiveness (Vol 28-4, Nov/Dec 2004), in stock form, "92% of the pump output, oil and dirt, go right to the various engine bearing surfaces". The stock 356 oil filtration system was very good in the 1950s, but engine life can be greatly improved without ruining your car's originality by fitting a full-flow oil filter. There are various designs and methods available which will provide full oil filtration to your engine, and they all have advantages and disadvantages. As a 356 owner, you probably have more options than any other vintage car owner. Breaking the Circuit Figure 1 – The bypass oil system. The plunger (A) would cover the main oil galley (3) during warm operation. ...