Building a 46mpg air-cooled engine

[MikeRG]

Author: Tom Chambers

From: "Building a 46mpg air-cooled engine."

Dune Buggies & Hot VWs magazine,

November 1980.

Method: A body in motion tends to stay in motion, etc.

The most popular story we've done in recent years turned out to be the series we di on our "project mileage motor". In it we tried to improve the intake and exhaust effiency of our 1971 bug's 1600cc engine to increase both gasoline mileage and performance. While we've still a ways to go before realising our goal of 40mpg, we are still working on the project and hope to bring you our final report sometime next spring. In the meantime we've received a number of letters and telephone calls from readers with projects of their own, some similar and others completely different from ours, yet still keeping the same goal in mind: better performance and gas mileage.

The most impressive of these was that of Jon Karcey, Makawao, Maui, Hawaii. Jon, who at one time built engines for some of the "name" Top Gas and Top Fuel racers on the West Coast, took a '68 Karmann Ghia, reworked the engine, improved its mileage from 27mpg to an astounding 46mpg. And if that's not enough, Jon feels that even 50mpg is very feasible with a little more work and experimentation. But the best part is that the project is not a mega-buck affair, and besides showing you readers most of the things he did to his engine right here on our pages, Jon also offers a detailed booklet showing exactly how to perform the modifications.

In Jon's own words, "After spending many years as a Top Gas and Top Fuel engine builder, I gained a lot of knowledge about the internal combustion engine. In later years I realised that the real race was who could stay away from the gas pump the longest." Jon started his engine project about four months before DB&HVWs project appeared, so he had a bit of a head start. Yet when he saw our story, it got his adrenalin flowing because the similarities were many and it was great to see that someone else was on the same path.

To get his project off the ground, Jon chose a '68 Ghia as his test vehicle - simply because it was available. Jon feels that a bug would be the ideal car, as it is lighter than a Ghia and there are so many fibreglass body parts available to lighten the car. Jon's theory was that if he built a "square" engine (square means that the bore and stroke are the same or very close) he could find the mileage he was after. Also, square engines put their power out at lower rpm, which is another plus when gas mileage is your goal. Using a tired 1600cc engine, Jon first replaced the crankshaft with a low-cost 76mm counter weighted unit. Since he wasn't going to "buzz" the engine, quality in the area of the crankshaft wasn't of prime importance. What was essential was high reciprocating weight, a body in motion tends to stay in motion, etc. The bore was then changed to 77mm (stock 1300). The crank and pistons were then enclosed in a Rimco clearanced case along with a heavy-duty oil pump and a reground Web Cam. Stock 1300 heads with some mild port work were also bolted on with a 0.120" fly-cut for a 9.0:1 compression ratio. The engine was then topped off with a pair of Solex Kadron carbs with homemade, smaller (25mm) venturis, a 009 distributor and a Bosch red coil. Everything else at this tie was stock and was designed to put out its power at low rpm. At 55mph, the engine delivered 38.485mpg with junk tyres and shocks. At this point Jon pulled the engine from the car and added a 12V 180mm flywheel, which was about 4lb heavier than the stock 200mm unit and, best of all, the weight was out on the end where he wanted it. Next came the 1962 Jaguar front engine pulley. After some machining and mounting a stock VW pulley hub, he ended up with another 10lb on the front of the engine. Total weight of the front pulley, crankshaft and flywheel came out to a 50-plus pounds of rotating mass. The last addition to the engine included the full range of Amsoil products for less friction, and afull set of Koni gas adjustable shocks on the Ghia. Now the Ghia really started to run, it had a lot more power than the stock 1600 and, best of all, at 55mph it delivered 44.101mpg.

After 2500 miles of driving, the engine was pulled to check it out and also because Jon had a few more things that he wished to try. All looked well, so all rotating parts were sent out to be balanced, the heads were subjected to some major reshaping, the stock rings were switched for a set of Total Seal units, and finally a Spearco water injection system was installed. After a bit of running the carbs were rejetted and ended up with #100 main jets! Yes, we said #100 - that's not a misprint. The final test on the engine at 55mph showed an improvement to 46.897mpg. With good plug colour, Jon still has a goal of 50mpg to reach, and feels that with a bit more refinement and a higher geared transaxle, it can be done.

Disclaimer: This article has been transcribed from a scan of a page of unknown source. If it infringes any copyrights, it will be removed from this website on production of proof of copyright.

http://www.southernvolksfolks.com/tech/46mpg.html

[alex_7]

Misto treaba si nici macar nu are injectie sau aprindere electronica si in

plus mai foloseste si un distribuitor centrifugal, tare rezultatul.

Trebuie studiat un pic sa vedem de ce a facut ce si cum si mai discutam.

Misto si site-ul are informatii bune.

Multumim lui MikeRG :)

Alex.