Hot VWs - May 2007 - Project Mileage Motor - Part 6
Our 1745cc powerplant finds a home
BY BRUCE SIMURDA
We've had more than a few calls from concerned readers regarding the absence of the Project Mileage Motor series in our April issue. Well, that was not because we ended the project, rather, it was because we were searching for the perfect candidate to install it into. That search ended when we came upon a very clean 1972 Super Beetle, in near stock condition with almost every component in working condition. This Super was maintained so well that it still had the original carb, air filter, distributor, even its charcoal evaporative canister was in its place and hooked up. Rest assured, all stock components will be retained in the event we choose to return this car to its original condition.
But for now, it was time to rip out the 1600 and install our freshly dynoed 1745cc Mileage Motor. Before pulling the old engine we did spend some time behind the wheel to get a good idea of what kind of mileage it was currently getting, but the tired mill could only muster up around 20.2 miles-per-gallon in a combination of about 60% highway and 40% city driving. So it wasn't long after purchasing the Super that it was driven into the back room, the car raides up on stands, battery disconnected, engine pulled and neatly stored away in preperation for the Mileage Motor.
At this point the engine compartment was cleaned and checked for any wear and/or damage. Besides a little grease and dirt, we were happy to find most things in proper working order. One area that did need attention was the rubber engine-to-body seal, which was brittle and cracked, and badly in need of replacement. It is importance that this seal be in good condition, to prevent the cooling fan from sucking in hot air it just blew out the bottom of the engine. Without the seal, air simply circulated around the engine, getting hotter and hotter as it does. We're often amazed at the number of "daily drivers" we see at shows that have this critical part missing, no doubt wondering why their cars run so hot. We also inspected the throw-out bearing and greased the (late model) support shaft it rides on, checked engine/trans mounts, and added fresh pan-to-engine fuel line and filter. With the engine out, we also took the opportunity to install a 6-wire harness from the trunk to the engine compartment, to handle gauges we plan to add in the future.
Before attempting to install the new engine, we pulled the dual carbs, muffler, distributor cap and wire, and fan belt to ease the process. We then hooked up the car's original metal fuel line, and made sure that throttle able tube was in the fan housing. Since ours is a later trans, the throw-out bearing "pad" on the pressure plate had to be removed from the Kennedy 1700. This was easily accomplished by pulling the pressure plate from the flywheel, then removing the spiral ring on the inside and then the pad from the outside. With that procedure done, the clutch was reinstalled, using a dummy input shaft to ensure the disc was aligned with the gland nut. The last thing we did before installation was cover the fresh air and preheat hose holes in the engine breast plate with sheet aluminum to keep the hot air under the car out of the engine compartment. Tin snips and a few pop-rivets, and we were ready to go!
With the engine ready to go in, we quickly discovered that the oil filter bracket we used for the dyno session was not going to fit in the '72 sedan, so it was removed. After that, it was your standard lift, push wiggle, curse... and eventually everything lined up. With that, the trans and engine cases met for the first time, and the four mounting bolts were tightened. At that point, you could definately hear one loud sigh of relief.
With the engine in, it was time to hook everything up. The first thing in was the carbs, which was perhaps the toughest part of the entire installation process. Unless you have hands the size of chicken feet, getting the 8mm nuts on those two front studs is one tough job! It does take perseverance, but be sure to have a telescoping magnet on hand to retrieve the nut or two you will drop down the spark plug opening. Once you manage to get a thread or two started, a long extension and perhaps a "wobbly" socket makes the rest of the job a cinch. And once the carbs were in place, the rest of the components - linkage, fuel lines, throttle cable, plug wires, electrical, fan belt, sheet metal, and muffler - went on without a hitch. For the oil filter we used a new Bugpack bracket that attached to the bumper bracket bolts and locates the filter just behind the left rear tire, although longer hoses had to be made.
Everyone was getting excited, as we prepped to fire it for the first time since it came off Jack Sacchette's dyno. With one last inspection to ensure that all fuel lines were tight, and all the electricals were in their proper location, the battery was connected, and the key turned. It took a bit before fuel reached the carbs, but once it did, the engine barked to life without hesitation.
Immediately, we again checked for any fuel leaks, and watched the engine mounted VDO gauge for signs of oil pressure - it was right in there at 55 psi. After a quick check of the timing we were ready for our first road test. With Dean Kirsten riding shotgun, we pulled onto Airway Avenue, and stabbed the throttle. Mileage motor?? Heck, with 92 horses this thing pulled like a performance motor! But it wasn't a top-end rush type of power like most hi-po VW engines provide, this was a strong, smooth, low rpm "torquey" type of pull that seemed to taper off rather quickly after 5,000 rpm. And right away we saw a problem - how are we going to produce good mileage figures when stomping on the throttle was so much fun?
With a deadline looming we tooke it out to get as many miles on it as possible. Luckily, all the tuning that Sacchette and crew had done a few months prior was unchanged, and the engine idled perfect, and throttle response was awesome. But it quickly became obvious on the freeway that the straight-cut gears might not be the choice for someone doing a lot of highway driving (noisy), and we could definately use some taller gearing. The engine was pulling approximately 3,200 rpm at 65 miles-per-hour with the '72 trans' 4.125 ring and pinion and 0.88:1 4th gear, which felt way too much for an engine with so much bottom-end torque. A gearbox with 3.88 R&P would certainly be better suited for this engine's power curve (57.5 horsepower and 120 ft.-lbs. torque at only 2,500 rpm). But for now, the combination of 50/50 highway/city driving netted us a neat 28mpg - not the 40 that's our ultimate goal, but not bad for a couple of heavy-footers having a lot of fun with their new engine. Besides, we still have a lot of testing and adjusting to go, with things like timing, carb jetting, different distributors, lubrication, tires, gear ratios, and ultimately fuel injection (system currently being tested is said to be "very promising"). There are also a few unique new products we'll be trying, which the manufacturers say will amaze us. Sounds good, but for the next coupld of days were going to see just how strong this '72 gear-box really is.