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Twin Plug Ignition in the 356 Engine

September 27, 2010 | Troubleshooting & Repair | 2 Comments
By Ron LaDow I wish I could credit this properly: I'm sure it was in a Henry Manny F1 review in Road and Track: "If you need two plugs, there's something wrong with your chamber". It related to a Maserati, and is suitably snotty, but there's a point there. 356 engines improve with the addition of a second spark plug in each cylinder. They improve in overall efficiency, both power and economy. And since the application does not effect engine breathing (with the resultant compromises), it improves matters at just about every RPM which has been tested. Improved overall efficiency means a 356 runs stronger, cooler and with less fuel. Firing Later, and More Evenly, Maximizes the "Rod Angle" The reason has to do with the fact that the mixture in the chamber must burn at a given rate, not explode. The burning causes the pressure to rise in the chamber, and that's what pushes the piston down that hole, connected by the rod, thereby rotating the crank. Ideally, the pressur...

Calculating Compression Ratios

September 27, 2010 | Troubleshooting & Repair | 0 Comments
Text by Richard Peattie and Ron LaDow [Editor] Richard Peattie and Ron LaDow have both developed Excel spreadsheets that enable you to calculate compression ratios when building up an engine. Ron LaDow [First download Ron's spreadsheet (Excel file) for calculating compression ratios]  The spreadsheet will only calculate the compression ratio; the measurements are up to you. Enter values in rows with italicized captions, as follows in the upper section: "Cylinder Bore" is entered once in cell B-5. "Arbitrary", "Net" and "Head Chamber" volumes are entered in columns E, F, G and H for each cylinder. "Add or Subtract Gaskets" entered in columns C and D; each changes both cylinders on a bank as thatís whatís required. In the lower section, enter: "Head Chamber" and "Piston Dome" volumes plus "Deck Height" are entered in columns E, F, G, and H for each cylinder Add or Subtract Gaskets" entered in columns C and D; each changes both cylinders on a bank as thatís w...

Starting an Engine after Extended Storage

September 27, 2010 | Safety & Driving | 0 Comments
By Alan Klingen How to handle an engine that has been sitting for years First see if you can turn over the motor easily, if not then you need to dismantle the motor to play it safe. If you can turn it over then remove all the oil, sump screen and oil filter, then refill with new oil of your choice. Do a regular tune with points, valve adjust and plugs but leave the plugs out for the time being. You can squirt a small amount of oil into the cylinders if it make you feel better but only a very small amount! Just a couple of drops only! Note on the dip stick where the oil level is exactly. Crank the motor with the ignition off by grounding the point wire to the coil, this is marked #1 on the coil. You don't want to just leave the cap off because it will be sparking inside and if you have a fuel leak and you are not there to see it, well you know what could happen. Crank for a few seconds and then recheck the dipstick and see if oil is being drawn, if it is crank some ...

Big Bore Pistons: Torque vs. Horsepower

September 27, 2010 | Troubleshooting & Repair | 0 Comments
By Alan Klinger and John Wilhoit [Editor] Dave Brenny asked a question on 356Talk wondering if rebuilding a 356 engine using big bore pistons produce more low-end torque at the expense of horsepower at high RPMs. Two 356 engine veterans responded: Alan Klingen, The Stable: No single item will make a motor"scream": it is a function of all of its parts. You can make a 1200cc motor feel real good to 10,000 rpm and you can make a 2000cc motor be a very good low RPM motor. The basic items that make a motor rev freely are the design of the cam, the compression ratio, and porting. There are a few others that come into play like timing ignition curve, fuel management, etc. I have found the biggest limit to a 356 to make good horsepower is the design of the heads: they are in a word, bad. A 911 can deliver 100HP/liter quite easily and be drivable, but to get a 356 engine over 75hp/liter takes some serious effort (and expense). Of all the dyno testing I have done it seems th...

Proper Engine Warmup Procedures

September 27, 2010 | Safety & Driving | 0 Comments
By Bud Osbourne The reason that engineers recommended the "drive away" warm-up, as opposed to allowing the engine to warm up at idle was that the faster the warm-up, the lower the build up of harmful condensation within the engine and exhaust systems. So, if you are only going to drive a short distance, you (your car's engine, actually) are better off just driving away after a very brief (30 seconds or so) warm-up, thereby allowing the engine to warm up quickly, and minimize the amount of harmful or corrosive condensation build-up, before shutting down. The majority of the engine wear occurs immediately upon start-up, no matter whether you drive right away or sit and warm it up. Your engine will incur less frictional wear if you let it warm up at idle (at as low an rpm as it will run at) than if you just drive away. However, if you slowly warm it up at idle and then drive only a short distance before shutting down, the condensation formed in the crankcase (which di...

Replacing Zenith Carb Top Cover Gasket

September 27, 2010 | Troubleshooting & Repair | 2 Comments
A Newbie Pulls a Carb — and a few other things By Steve Dempsey, with a lot of help from Ron LaDow and Tom Farnam I live in south central Missouri where 356 expertise basically doesn't exist. The nearest shop recommended by fellow 356ers is in St. Louis, about 160 miles away. Recently I discovered the top cover gasket on my driver side Zenith 32NDIX carburetor leaking. Since I couldn't just drive over to a shop and drop the car off, I sent an e-mail to 356Talk to find out if I could replace this gasket without removing the carburetor, something I really wasn't confident in my ability to complete successfully. Although I was assured by several on the list that this indeed could be done, the consensus was that the job was easier if I removed the carburetor. I decided to give it a shot, and as it turns out, this job is really something anyone with basic skills (and a little muscle) can handle. No magic! Tools Needed "Wide" screwdriver or 14 mm socket and lon...

Zenith Carburetor Bases: Making Them Flat!

September 27, 2010 | Troubleshooting & Repair | 2 Comments
By Bruce Tews I do not like leaks of any kind, whether they be engine oil, transaxle oil, or gas, and maybe, especially gas. So, my Zenith carbs leaked, and I was not going to tolerate the leaks. Mine no longer leak, and this is how I fixed them. First, get yourself a mirror. Mirrors are extremely flat. A one foot by one foot mirror panel from Home Depot or Lowe's is perfect. Also get some JB Weld and liquid teflon in a tube. (More on these later). Tape the edges of the mirror to a flat place, maybe the countertop next to your kitchen sink because you need water for the emery cloth which you will use. Then, if you are up to it, take your Zenith sections apart and do what Ron and others suggest, which is, tape a piece of 300 to 400 grit emery cloth on the mirror and resurface the flat sections of the carbs. Second, follow their other instructions regarding float levels, etc, including not removing the screw within a screw under the middle carb section. Thir...

Making Your Own Fuel Lines

September 27, 2010 | Troubleshooting & Repair | 0 Comments
By David Jones Provided by Phil Planck: Dimensioned drawing of the short fuel line between the filter and pump on 356 pushrod engines prior to late 1955. It will correctly locate the fuel filter so that it can be disassembled on the car, and properly match up to the fuel line. The fittings and ferrules were available at VW dealers when he made his circa 1990. Print size image Printable PDF file. Ken Daugherty gets his steel tubing from NAPA, PN 813-1235 (5/16" x 60"). See his article on Fabricating Weber Fuel Lines   I decided that as most folks do not know how to bend tubing, that instead of doing it the hillbilly way by bending the tubing around various diameters of pipe I would buy some cheap benders and test them out. The red handled benders were from Advance Auto and cost $10. The longer chrome plated ones are professional tube benders designed for bending stainless steel which is malleable only once: if you don't get it right the tubing is jun...

Identifying a Solex Split Shaft Carburetor

September 27, 2010 | Research & Identification | 0 Comments
Text and photos by Nick Warinner, scans courtesy of Ron Domkowski [Editor: For those seeking to distinguish between the Solex 40 PII and the split-shaft version, here are some very detailed photos with comments by Nick Warinner, and below that scans from the workshop manual, courtesy of Ron Domkowski.] Split-shaft on the left, solid shaft on the right. Photos below by Nick Warinner Scans below by Ron Domkowski

Solex Split Shaft Carburetor Conversion: Full Size Photos

September 27, 2010 | Troubleshooting & Repair | 0 Comments
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