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Tech Q & A
PCA Tech Committee Database - click to enlargePCA Members, ask the National Technical Committee all your 912/912E questions, plus search all questions and answers, by visiting the PCA Tech Section webpage!

Following are sample 912/912E questions.  Watch for tech discussion in PCA's Panorama magazine as well. 

912 Speedometer Cable
912 Battery Problem
912 Fuel Pump
912 Oil Consumption
912 Carpet Care
912 Oil Cooler Replacement
912 Engine Gasket Set
912 Tire Size
912 Transmission
912 Karmann Bodies
912/912E Comfort/Maintenance
912E Shocks for Autocrossing
912E Engine Miss
912E Fuel Injection Hesitations

Questions related and relevant to the 912/912E

Fuel [containing ethanol]

Steering Rack
Touch up Paint
912 speedometer cable (July 2012 Pano):  How do you replace the speedometer cable in a 912?

David Seeland: If you are lucky, just the core of your speedometer cable is broken and you can just replace the core.  Check for a broken core by attempting to pull it out at the speedometer end.  If it is broken pull the other end out at the speedometer drive at the front of the transmission.  Insert the new core from the rear, reconnect and you are probably done.  If you need to replace the whole cable, access to the inside of the tunnel is needed: remove seats, rear tunnel cover, gearshift, handbrake but not handbrake cables, and front tunnel cover.  Open the clips holding the cable in the tunnel at the brake and shifter holes.  Remove the grommet where the cable enters the interior from the trunk and pull the cable out of the hole at the rear of the tunnel.  Put the boot from the rear of the tunnel onto the new cable from the speedometer end of the cable, then insert the cable at the rear of the tunnel after taping the knurled knob used at the back of the speedometer to the end of the cable.  Route through the metal clips and bend them back down.  Be careful so that the speedometer cable doesn't interfere with the shift rod or clutch cable in the tunnel.  Don't kink the cable while installing.  Reinstall all the stuff you removed.  While you are there check the white nylon bushings on the shifter and shift rod.

912 battery problem (April 2012 Pano):  I have a '66 912.  The battery does not get recharged when driving.  The car will run once jump started by rolling forward and popping the clutch.  However, after it is shut off, there is not enough juice in the battery to start it.  I have purchased several voltage regulators and replaced them.  I have also checked the generator and the brushes seem to be OK.  I have purchased a second ignition switch and that does not change the problem.  I checked the fuses and cleaned all of the corrosion seen.  I have also replaced the starter motor and insured all connections were clean.

David Seeland: It seems that your car either has a bad battery or a bad generator.  If you don't have one, purchase an accurate digital voltmeter.  In addition, I recommend a digital voltmeter that plugs into the cigarette lighter that allows you to monitor the charging system as you drive, I bought mine from GoWesty.  They are all precise, reading to tenths or hundredths of a volt, but not necessarily accurate.  A fully charged 12v battery, that has sat overnight so that the surface chare has dissipated, should read 12.6 volts.  If it reads 12.0 volts it is only 25 percent charged.  Have you tried to charge your battery with a battery charger?  Does your 912 start after charging the battery?  If you have been having this starting problem for a long time, then you car's battery many no longer be good as they don't like being deeply discharged for long periods of time.  Use a battery terminal cleaner on the terminals, on the inside of the ground strap terminal, and on the inside of the positive cable clamp.  Charge the battery and take it to a parts store and they will check it.  A 12v generator should put out nearly 14 volts, read across the battery terminals, at 2000-3000 rpm.  Try applying a little pressure to the brushes while the engine is running to see if the voltage increases.  If it does, the brushes may be too short and should be replaced.

1968 912 fuel pump (October 2011 Pano): I have tried several over-the-counter electric fuel pumps (bypassed the mechanical pump) with poor reliability.  I drive the car only on "sunny Sundays" and want to be able to get fuel to the carburetors without having to crank the engine a long time to operate the mechanical pump to fill the float bowls sot he engine will start.

David Seeland: Rather than using the electric pump full time, use the electric fuel pump to fill the carburetor float bowls and then run the engine using only the mechanical pump.  Filling empty float bowls will take less than 60 seconds.  The pumps will work fine in series.  Place the electrical pump close to the tank.  Pumps are better at pushing rather than pulling.  Zims Autotechnik has a momentary on/off/on switch for use with an electric pump and also sells a 12v Pierburg low-pressure pump that does not need a pressure regulator for full time use.  Zims also has a 5-8 PSI 6v pump that will need a pressure regulator to get the pressure down to 2-3 PSI.  I have had, and heard of, more problems with pressure regulators than with pumps.  I recommend a Holley pressure regulator that is available from Pegasus.  NLA has a 6-12v electric pump.   For those of you with 356s, there are electric pump installations available online at  This website has general and safety information that will be valuable to 912 owners too.  While you have the fuel system apart it would be a good time to add a large metal fuel filter available from Zims and others under the car, particularly if you have a plastic filter after the pump and in the engine compartment as many cars do.

1976 912E shocks (September 2011 Pano):  My car has the original Boge shocks and struts.  I had the car lowered by a Porsche mechanic for an occasional autocross.  He explained how he did it with the torsion bars.  The ride for the street has become very stiff, bone jarring in fact.   Do I need new shocks and struts, or do I need to raise the ride height back up a bit.  Right now the distance from the floor to the lowest part of the car at the front suspension is about three inches -- right under the gas tank.  OR a combination of both?  I also run a 50 series tire instead of the original 65 series.

David Seeland: I think you are right about raising the height because it appears that your shocks are bottoming out.  Racers use front struts with raised spindles to lower the front without bottoming out the shocks.  To avoid bottoming at the rear, shorter rear shocks would be necessary.  Stiffer torsion bars both front and rear (22 front and 29 rear) would help stiffen the suspension and keep the tires flat when autocrossing and paradoxically make the care more comfortable on the street because the suspension would bottom less, or not at all.  Anti-sway bars front and rear would also help.  Lowering the car by itself without any other suspension improvements slows the car while autocrossing (no suspension compliance at all when the shock is bottomed out) and makes it uncomfortable on the street.  If all these modifications sound expensive, they are, and the least expensive way to improved autocross times (after improving the driver) is to get some R-compound tires on a set of extra rims.

1969 912 cleaning carpet (July 2011 Pano):   How do I clean the charcoal/Perlon carpet in my 912?  There are no spots, just embedded soil.

John Paterek:   I washed my original 1952 America Roadster wool carpet with cold water Woolite.  The pieces were soaked in it then stretched out to dry in the sun.   The carpet is still in the car 29 years later.  I feel it will remove most of the soil you are concerned about without any harmful chemicals.

1969 912 oil consumption (June 2011 Pano):   I have a 912 with 120,000 miles since an engine rebuild at 83,000 by [the late] Harry Pellows.  There is no smoke but the engine either uses or loses one quart every 100 miles.  Factory specifications indicate one quart every 300 to 400 miles.  What do you recommend?

David Seeland:  I think Pellow used lots of NPR big bore kits and those do not last as long as stock Mahle pistons and cylinders so the NPRs could be worn out.  I once had a Corvair engine in a 23-windo VW bus that suddenly began consuming a quart every 100 miles and it didn't smoke either.  The air cleaner had slipped partially off while driving around the Four Corners area on dirt and gravel roads.  The carburetor throats were coated with red dust and the rings and cylinders were worn well beyond reasonable tolerances in only a week.  If the onset of your problem was sudden then you may have broken rings -- unless you have spent a week off road with mesh air filters.  Before you have somebody rebuild the engine, have leak down and compression checks done.  Look at the plugs for evidence of oil fouling.  Park on clean concrete or cardboard to check for drips.

912 oil cooler replacement (January 2011 Pano):  I rebuilt my 912 engine 19 years ago and have been vintage racing the car for some time.  The oil temperature seems too high to me.  Do you think one of the new, probably more efficient, aluminum coolers that replace the original cooler would help?

David Seeland: Yes, it should cool better than a stock cooler and be less likely to crack the case because of the lighter weight.  However, if you haven't cleaned the cooler by removing the fan shroud in 19 years, your engine's present oil cooler is almost certainly clogged with oily dirt.  Furthermore, the tops of your cylinder barrels probably have enough dirt to grow carrots (if carrots liked oily dirt).  I would remove the engine, the fan shroud and cylinder sheet metal and carefully clean the cooler and cylinders and reinstall the sheet metal.  After cleaning, the engine oil temperature should be substantially lower under similar circumstances.  If it still isn't cool enough, then try the aluminum cooler.  Try to eliminate as may oil leaks as possible, particularly pulley leaks that spray oil into the engine compartment air.  Otherwise the engine oil temperature will soon be back up again, because the oil cooler and cylinders will collect more oily dirt.  I have a mild 356 race engine with about 45 hours that had cracks in the bellows area of the pushrod tubes, so I removed the sheet metal and heads to replace the tubes.  I wouldn't have expected it, but the cooler on my engine was at least ten percent blocked by dirt although the cylinders were clean.  The engine still ran at less than 210F under race conditions in 96F ambient conditions, but it has a fairly large front cooler in addition to the stock cooler.  If 45 hours will partially clog a cooler, think what 1000+ hours will do.  Keep the cooling surfaces clean by minimizing oil leaks and by cleaning under the engine sheet metal every two or three years.

912 engine gasket set
(December 2010 Pano):   I am about to start putting my engine together.  I have a gasket set that is around 9-10 years old.  Is it wise to use that ld a gasket set or should I purchase a new one?  Are newer gasket sets for the 912 really new or have they been in the parts distribution system for a short or long time?

David Seeland:   I wouldn't worry too much about the age of the gasket set because most 356s [912s] on the road have gaskets that old in them and the gaskets have been heat cycled many times and still seal just fine.  Yours have led a cool plastic-wrapped existence and should be fine.  That said, buying new Viton crank and pulley seals would be a good thing as they are much better than the stock seals.  New gasket seals really do seem to be new as the packaging keeps changing.

Tire size for 1968 912 (February 2010 Pano): I have found two responses to tire questions that seem to be contradictory: I think a 195x60 tire would be closer to a stock 165x15 tire diameter and should feel better.  If you have a 5.5x15 or 6x15 wheels, I recommend 185/70 or 195/65x15 tires.  I have 6x15 original Fuchs wheels (part number is 901.361.012.06) and am thinking about 195/65/15 tires.  Should I go with the 60 as the middle number?  I was told by other sources that no modifications to my car (1968 912) need to be done and that the tires should have no clearance problems.

David Seeland:  I don't know what tire the 195/60 was being compared to.  If you want gearing to remain stock, then tire diameter should be stock, about 25.25 inches.  You might want smaller for more acceleration or you might want larger for better fuel economy.  The other parameter you should consider is rim width.  There is a range of tire widths that are acceptable for each tire size.  Your six-inch wheels are too wide for 165/80x15 stock tires so you must choose a wider tire to fit your six-inch rims.  I have recommended 195/60 because I like the improved acceleration and the visual relationship between the tire and the wheel well on the lowered car.  A 50-series tire on a stock height car looks strange.  The tire has to fit the rear wheel well without rubbing.  A 195/65 is closer to stock diameter and should fit.  Spacers and longer studs are sometimes necessary depending on the wheel offset.  Mounting one tire and trying it on the rear might be wise.  Compromises on size are sometimes necessary if a satisfactory tire is not available in the size you prefer.  The 15-inch tire is not as widely used as it once was and choices are fewer.

912 transmission (October 2003 Pano): Can you tell me which transmissions were used in a 1969 912?  Is it the 901?

David Seeland:  A 1969 912 uses a magnesium-case 902 transaxle, either a four-speed or a five-speed.  A 901 transaxle from a 911 will have the same gear rations and will fit a 912 without modification.  Magnesium-case transaxles have a bigger pinion bearing than the earlier aluminum case transaxles.

912/912E Comfort (July 2006 Pano): I guess I am old school at heart.  For the most part I subscribe to the idea that most of the great cars were pre 1972 when the smog regulations started in earnest.  Last week I drove a 1976 912E for the first time and was totally blown away by the difference in comfort level (from my '69).  The cabin feels much more spacious, seating is much lower and the elbow room with two aboard is much better.  Jake Raby calls the 912E the ultimate touring car and now I understand his infatuation.  These cars are no ready to become smog exempt here in California and seem to be modestly priced.  Are maintenance costs any better or worse than their older brothers when used as a daily driver?

David Seeland:  A I have heard of amazing long-lived 912E engines.  They were designed some 20 years later than the 356 engine of the original 912 and have improvements in many areas.  Full-flow oil filtration is a big improvement that preserves main and rod bearings.  The fuel injection is very reliable.  Hydraulic lifters could easily be installed without complete engine disassembly to eliminate valve adjustments.  Parts are less expensive and easier to find because it is a VW engine for the most part.

Karmann bodied 912 (Pano): On the driver side doorframe is an ID label.  This label is marked "Karmann."  What does this mean?  Are any marked "Porsche?"  On earlier 912s this plate had chassis serial number and paint code.  On 1969 models only the paint code appears, why?

David Seeland:  Karmann was a German body manufacturer that Porsche and VW (the Karmann-Ghia) used from time to time.  Karmann [almost] only built non-sunroof coupe bodies for the 912.  The remainder of the 912 coupes, Targas, and [almost] all sunroof coupes were built by Porsche who by 1965 owned [the former] Reutter [body factory], the source of the majority of 356 bodies.  My guess is that the ID plate did not say Porsche because that would be unnecessary.  In 1969 Karmann was still providing bodies so I don't know why Karmann wasn't on the ID plate unless you have only looked at Porsche-built cars and that is not on the ID plates as I have surmised.  I would appreciate a phone call from anybody that has "Porsche" on a 912 ID plate. [Commencing with 1969 model year vehicles sold in the USA, the chassis serial number/VIN was required to be visible under the windshield, lower corner drivers side.]

912E Engine Miss (July 2011 Pano):   I have replaced the air-flow meter, manifold intake hoses, the spark plugs and have replaced the points with electronic ignition.  The car still misses at around 3500 rpm.  Could you suggest what I should check next?

David Seeland:  There are still some ignition components that you haven't replaced: ignition cables and plug ends, coil, rotor, and distributor cap.  Check your battery voltage to be sure the charging system and battery are good.  Check the voltage after letting the car sit overnight.  The reading should be 12.6 volts for a fully charge battery.  Try to determine which cylinder is missing by disconnecting one plug wire at a time.  The miss will disappear when the missing cylinder is disconnected.  I suppose the miss could be a lean miss and unrelated to spark.  Buy another injector and replace the injector on the cylinder that was found to be the culprit.  If all this fails you might need to take it to a shop that has an ignition scope, and knows how to use it.

912E Fuel Injection Hesitations  I've got a problem with my [912E] fuel injection that can't be so unique or complicated that someone hasn't previously  diagnosed and solved it.  I'm experiencing intermittent gas starved hesitations, bucking, when accelerating (especially through the gears when reaching about 3200rpm) If I back off it smooths out.

Ed Mayo: A lot of "could be's" on this, the injection is basically the same as the 914 1.8 series. A good starting point (pun intended) is to absolutely verify that the ignition points are correctly gapped and not bouncing due to a weak spring or improper installation. The ignition points are the trigger for the injection vs. engine RPM. I have also seen this problem due to weak spark plugs. These can be difficult to track down, but you gotta start someplace, do the easy ones first!  Chris Powell: I agree with Ed, and would add that another common problem is faulty seals on the oil cap. Another easy place to look. After that, all tune-up specs should be verified, along with fuel pressure and delivery volume.

Related and Relevant Topics:

Fuel for 356B (March 2012 Pano): What type or grade of gasoline should I use on [a] 1961 356B Super?  All gasoline in my state is mandated to have 10 percent ethanol.  What precautions do I have to take, if any, in terms of the engine performance?  Someone suggested adding tetraethyl lead, but that is no longer available in this country.  Also what should be done about long term storage of gasoline/ethanol in the tank?  What could or should be done to prevent rust, etc?  I am not even sure if the carburetor parts or others in the fuel system of this old class are resistant to ethanol.

616 Engine Fuel Lines Parts ListDavid Seeland:  I expect you are not going to use this as a daily driver. I would buy unleaded race gas for any non-catalyst car that will likely be driven very little.  It costs about twice as much as premium but has no alcohol and does not go bad as rapidly as ordinary gas.  It wouldn't hurt to add Sta-bil to the gas.  Keep the tank full to avoid condensation.  The valve seats are hardened steel so lead is not necessary.  Replace all the cloth-covered rubber fuel line.  You don't want to soak the interior in gas or have an engine fire.  New German hose that looks exactly like the original is still available from most of the 356 parts suppliers.  Don't forget the three-inch section between the carbs behind the fan shroud.

Steering Rack (October 2012 Pano): I'm refreshing a 1971 911T that sat for 20 years.  I notice the steering rack has dirt accumulated around the areas adjacent to the boots.  Should I inspect this more carefully?  Do you recommend that I remove the unit and check inside the boots?  If it is leaking, does anybody rebuild it?  They are about $1000 from Performance Product, and that's a rebuilt unit.  I'd like to keep as many parts of the car original as possible.  It looks like I'm going to have to replace everything that's rubber.

David Seeland:  I'd say all you need to do is remove the rack and clean it with degreaser.  Then remove the spring clamps and pull back the boots.  It will probably still be clean inside; if so just replace the boots and spring clamps and you should be good to go.  So far I personally have yet to see one of those racks wear out.  Not saying it can't happen, I just haven't seen one yet.  What you more likely do need to replace is the rubber coupler between the rack and the steering shaft.  Those do wear out.

Touch up Paint (December 2012 Pano): I have a signal red 356SC.  It was repainted in '95 to a very high standard.  The color match with the original un-repainted panels is exceptional.  I know there isn't touch up paint available through Porsche for my car, but was wondering if there is color available that is a close match to signal.  Regardless of how careful I am, I get an occasional stone chip .

David Seeland:  Take a hinge cover to an automotive paint store and have them match the a pint in acrylic enamel.  It will be very expensive.  Red is one of the more expensive paints ($400/gallon).  Get a half pint or whatever minimum they allow.  There are websites that sell paint to code but I think your car is too nice for an almost match.

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Rick Becker, PCA 912/912E Advocate
Pacific Northwest Region

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