/Engine ProductsOpen to everyone

The flywheel seal that kills engines

Replacement seals for both the flywheel and the crankshaft pulley now ship as double lip seals. The crankshaft pulley can run one without trouble, but on the flywheel a double lip seal is dangerous. The flywheel end is machined with a radius, and that radius rides on the dry outer dust lip until it fails. Heat and debris then take out the inner sealing lip and the engine dumps all its oil at once. One customer’s freshly rebuilt engine spun its rod bearings on the highway when the green oil light came on, by which point the oil was already gone.

Crankshaft pulley seal and pulley install

The crankshaft pulley has no radius, so the extra dust lip on a double lip seal touches nothing and does no harm. A double lip seal on the crankshaft pulley is fine to run. There is no VW aftermarket shortcut here anyway, because VW uses a reverse thread and offers no crankshaft pulley seal.

Installing the pulley: set the OT mark (TDC) on the crankshaft pulley to 3 o’clock, which puts the keyway straight up at 12 where you can watch it seat. If the key wants to walk, lock it to the crank with a drop of super glue. Install with the RTV bead still wet, hold the pulley with a proper tool, and torque the nut to 47 foot pounds, not the several hundred people assume. Never hold the pulley with an extension jammed through a crankshaft pulley hole. You will break the cover. One owner broke off enough that the gears were visible from outside the running engine.

RTV stays out of engine assembly with one exception: a thin 360-degree bead inside the pulley bore where the crank stops, plus a smear in the keyway, to seal seepage between the pulley bore and the crank that is not the seal’s fault.

Stopping oil and steering leaks

A leak at the flywheel end is often not the seal at all. It is the dowel pins, where tiny clearances open up from reusing existing parts. Before the engine runs, apply Permatex 290 to the dowel pins. It wicks into the gaps and cures where it is deprived of air, and it does not make fasteners hard to remove later. Tim treats it as a belt-and-suspenders step and uses it the same way on case seams after assembly, at the acorn nuts, on through bolts, and anywhere oil might start to weep.

For the steering box, Tim adds Lucas Heavy Duty Oil Stabilizer to slow or stop leaks. The same product works in gear boxes. This is his recommendation rather than a factory or Registry spec.

Fuel system: smell, hot starts, and flow

Gas smell in the garage and hard hot starts

Reformulated fuel reacts to heat worse than what these cars were built for. Shut the engine off and the carburetors and manifolds heat sink, the fuel in the float bowls rises, and it dribbles out the ejector nozzles into open bowls with breathers. Two fixes: set the float level to the minimum of factory spec, and on a 356 shut the fuel off 30 to 40 seconds before you kill the engine to drop the bowl level. Lower bowls also make the hot restart easier instead of flooding the motor.

Fuel line permeation

By Gates’ own numbers, two feet of conventional rubber fuel line passes about four liters of hydrocarbon vapor a year, and a 356 runs four feet or more from the bulkhead under the jump seats around through the tinware above the gearbox. Replace it with Gates Barricade, a multi-layer line that is essentially impervious to alcohol fuel. You can buy it by the foot at a parts store. Replace the forgotten line ahead of the fan shroud while you are there, since it cracks like a dry twig, and reattach with fuel injection style full circle clamps that do not deform the rubber.

The factory “filters” are strainers

The tank mesh, the petcock screen, and the plastic strainer at the pump are strainers, not filters. Ethanol scours the tank and lines and makes more debris than those catch. Add a metal-bodied fuel filter on the output side of the pump and hang magnets on it. The ferrous powder that collects, talcum fine, gets thrown into an idle jet when you corner hard.

Ignition and engine-bay wiring

Bosch quality has fallen off, with plugs from former Iron Curtain plants and points and condensers from Turkey. The condensers in particular are unreliable.

• Condenser: for a cast iron distributor, buy a GB125 at a regular auto parts store. It fits the factory holder and lasts. Trim the slightly long wire and add a ring terminal with shrink.
• Distributor cap: use Wolfsburg West for the cast iron distributors. Correct fit, color, and contacts, and cheap. Avoid the brown caps from some vendors that use aluminum contacts against the brass connectors on the plug wires, since the dissimilar metals corrode.
• Wiring: use marine-grade adhesive-lined shrink. The glue inside waterproofs the joint and adds mechanical strength. An assortment is available at Harbor Freight and is actually good.

Cylinder heads and compression

New CNC cylinder heads (available about two years) are the fix for worn originals. Worn heads lose material from valve jobs and from fly cutting the sealing surface where the cylinder meets the head, since there is no head gasket and that face wears. Some machinists take two or three thou, others arbitrarily ten, and cutting inside forces a matching cut on the outside to keep the dimension between the top fin and the head.

The factory ran chambers at the big end of the range to leave room for future fly cutting, which bites you on a rebuild. With JE Shasta-design pistons (nominal 9.25) you can pour the chambers and land near 8.8 to 1, lower than most want for the street. The fix without machining is below.

Measure deck height with solder. On fly-cut heads, also measure valve-to-piston clearance and the exhaust valve pocket, since the head has moved in. For fine shim adjustment, CB Performance VW 1500/1600 cylinder shims fit the 356 and 912, and their loose quality control means a pack marked .010" actually runs .008" to .012", which you can sort to balance one head against the other.

Case and measuring tools

Bearing crush should be about .003", meaning the assembled bore is .003" under the bearing outside diameter. Large or oval bores lose that crush and you start with low oil pressure. A dial indicator rarely repeats. Two tools from Precision Matters (Ron LaDow) make it repeatable:

• Case measuring mandrel: cut exactly .003" under nominal bore. Plastigage four spots per bore, torque, and read. About $250. Tim’s tip is to treat it as tool rental and resell it on the 356 or 912 bulletin board, where it sells in a day.
• Top-end CC kit (82.5mm to 90mm): a plexiglass plate fills the chamber conically at 12 o’clock with no trapped air, unlike CCing through the plug hole at a 45-degree tilt that leaves a fat cc you cannot see.

For case machining he points to Competition Engineering (Walt Watson), founded by Ray Litz in Pasadena in the 1960s.

Oil cooler

Aftermarket aluminum coolers are lighter, so a full cooler vibrates the case less and cracks it less. Two cautions: with a stock bypass filter, a failed engine turns the cooler into a debris trap, and you cannot trust a cooler by its stamps. Tim has pulled coolers covered in “good to go” markings, both rebuilt and brand new, that leaked from a dozen pinholes.

• Pressure test every time. Build a tester for about $20 from a dune buggy oil cooler adapter ($10 used, $20 new on eBay): plug one port, fit an airline on the other, and test at 60 psi.
• Paint the raw aluminum. New coolers come mill finish, not anodized, and pollutants attack the bare metal. Mask the latticework and shoot VHT high-temperature wrinkle paint, good to 350. The wrinkle adds a little cooling surface.
• Install the seals in the cooler, then lower it onto the case while eyeballing the case ports. Aluminum coolers have sharp machined holes with no self-aligning radius, and the seal is only about .012" smaller than the hole, so the factory drop-on method usually nicks a seal.

Full-flow oil filter

With only the stock bypass filter, Tim claims none of your oil passes through the filter on a drive under 200 miles. His recommendation is the Precision Matters CNC oil pump cover with an internal elbow that routes oil out to a filter and back through the normal path, so the bypass and pressure relief valves still work.

It has to go in with the engine out, both because of the swarf from removing internal material on the third piece of the case that the cover needs to work, and because the factory set the cover’s dowel pins after assembly to a found sweet spot. Trial fit on the bench in a padded vise and tap it around until the gears spin a full 360 freely, then install the timing cover with the oil pump gears as a unit, lining the cam slot to the driven gear tang.

Gaskets: measure them

Universal Renz sets ship wrong parts. The oil pump gasket spec is .008" compressing to .006", and sets have arrived at .015", which reduces oil pressure measurably. Measure every gasket that has a spec.

• Order from Wrightwood Racing (carried by Stoddard and Competition Engineering) by exact year and engine, so you get correct parts and none of the filler: the three sump gaskets only a recalled Super 90 thimble setup needed, or wrong-thickness valve cover gaskets.
• Throw away the distorted clear plastic cooler seals from the Renz kits. Once they take a set out of the shrink wrap, no mandrel, boiling water, or sun cycling makes them round again. Buy the correct red or brown seals.

Sump plate, rocker arms, pushrods

Sump plate

Stamped steel plates distort and leak where the riveted magnet loosens from overtightening. The Precision Matters aluminum plate cannot distort and puts the drain at the lowest point, so you draw off the worst sludge. Add a hard cad-plated hardware-store magnet, not the dark gray pressed type, which is essentially compressed magnetic dirt and has no business sitting in hot oil. The one weakness is the stock bolt hangs below the plate and is exposed; one customer scraped it in a pothole and it wept. Swap to a flush McMaster-Carr plug of the same thread, Allen drive, with the magnet on the inside end.

Rocker arms

The Willhoit kit is $1,000 against roughly $4,500 buying the pieces. It includes shafts, rockers, springs, spacers, top hats, the center bearing block, and all the hardware, everything but the carrier. Factory replacement rockers at $400 each are decades-old stock and measure out of spec, with the intake-to-exhaust ratio (should be 1.3 to 1) all over the place. Willhoit’s check out, and the adjusters have an Allen socket in the stem so you can hold the setting while you torque the lock nut.

Pushrods and the wood inserts

Late A normal engines have wooden inserts inside the pushrods, with pickle-fork ends so they do not block the oil hole. If a plug shifts and caps the oil hole, the whole valvetrain starves and chews up rockers and shafts, and cleaned out they will not even rattle. Match pushrod material to cylinder material (the barrel): steel pushrods with cast iron cylinders, aluminum with aluminum, or valve clearance goes wrong and you burn valves or it clatters. The 912 uses stainless pushrods with steel tips, the ones Tim finds bent most, and a mechanic who substitutes plain steel pushrods may not know they are full of wood.

Tires

Tires die by age, not tread. The session opened with a 356C on a perfect-looking tire that was failing from age.

• Read the four-digit DOT code: week, then year. DOT says six years maximum, which is argued.
• Buying mail order is the trap. Ask the seller their date-code policy before ordering. Costco will not sell a tire over one year old.
• Heat cycling in transit and ozone age the rubber whether you drive the car or not, so a listing that implies correct storage may not mean climate-controlled storage.

Tools and small fixes

• Synchrometer: the butterfly counterweight can drop out and get sucked into a running engine, which Tim watched destroy a fresh motor in seconds. It happens on the genuine German unit, not just the clones. Put a $1.49 piece of plastic window screen in the basket so it cannot escape.
• Grease coupler: a LockNLube coupler locks onto the Zerk and frees a hand. About $25, or $34 with spare seals.
• Fuel-contact gaskets: seal them with Permatex Gasket Dressing, the clone of British Hylomar. It is fuel proof and resinous, so apply a thin coat, let the carrier flash off, and install so none migrates into a carburetor passage and blocks it.
• Magnets: drop them in the petcock strainer cup and on the metal fuel filter to catch ferrous grit before it reaches the carburetors.

Parts and sources Tim named

Wrightwood Racing sells through dealers (Stoddard, Competition Engineering, Pelican Parts) rather than direct.

Disclaimer