I just bought a '78 Super Beetle convertible.  Although this is my 71st car since 1984 I know NOTHING about Super Beetles.  This car had been extensively modified and I am trying to identify the engine size and year so I can buy the proper parts in the future.  The car itself is in outstanding condition.

The previous owner knew nothing about cars and he didn't build it.  So, here is what I have come up with so far.

1. There are NO identification numbers stamped on the front pad on the block as all manuals say the block should.  They have neither been machined off nor scraped.  The block looks like it has never had them on it.  One Beetle "expert" in Virginia Beach, VA said it's probably not an original factory block when he looked at it.  Another "expert" in Grand Rapids, MI said the same thing.  But neither one of them knew for sure.  They couldn't tell.

2. It has a 34 PICT instead of the original fuel injection. There are no vaccum lines to anything.  There used to be some box on the right side of the firewall that had large vacuum lines.  The box has a decorative billet aluminum top, but is now not connected to anything.

3.  It has dual port heads.

4. The distributor does not have any vacuum lines or any sort of vacuum mechanism on the outside.  It is a points distributor.

5.  The harmonic balancer has two barely distinguishable lines in it (maybe).  You can hardly tell.  And neither line corresponds to anything near TDC when you line it up.  I found this out the hard way when I moved the distributor to time it and then tried to move it back to it's original spot.  Now it's just wrong.

6. And most confusing to me, until recently this thing ran like a raped ape.  It blasts off on acceleration and can EASILY run 105~110 MPH on the highway.  It's not going to set any speed or acceleration records but it sure isn't a stock Beetle engine from what I can tell.

Can ANYONE please help me figure out how to ID this engine?  It just now started running rough and ticking hard, so I'm looking to start tuning it properly.  Thank you in advance!

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No way to tell without some surgery. It is possible to measure the displacement with something called a "P&G pump" after removing the plugs and rockers (a racing association or local track may have such a tool for tech inspections, but good luck getting anyone to loan one out). You can also make a crude approximation of displacement by seeing how much light oil it takes to fill a cylinder with the piston at BDC (and the engine tipped up on that side) but it'll only be as accurate as the assumption made for the compression ratio. The amount of cylinder head work (valve size/porting) has a lot to do with the power output too - but again you can't really tell what you have from the outside. Sometimes you can make out a number cast into the bottom of one of the cylinders where it plugs into the case - that'll give a clue as to the bore, but you still won't know the stroke. 
All original engine cases have numbers. Anyone who doesn't know that beyond a shadow of a doubt is no expert. On a Type I they're stamped below the gen/alt pedestal, on a Type III they're on top of the case and could be obscured by the sheetmetal if it's used to build a Type I. Your original F.I. case had no provision for mounting a mechanical fuel pump. The country of origin and the alloy (AS41 or AS21) should be cast into the sides of the sump underneath; the diameter of the head studs (8mm or 10mm) and whether they're screwed directly into the case or into steel inserts, and the number of oil pressure control valves (~1" diameter slotted screw-in plugs on the bottom of the case) will help to identify it; so will the absence/presence of horizontal ribs, like a little washboard, cast into the panel above the dipstick. Even with all of this information it probably won't be possible to positively identify the case, though, since things can be changed over 30 years. But the largest displacement stock engine ever put in a Beetle was 1585cc - larger motors are all built using aftermarket parts so ID'ing the case is of no use in determining the size.

Look for a number on the distributor body. Most likely it's 0 231 178 009, a popular replacement centrifugal-advance-only distributor. Timing on this one is set at 30-32°BTDC TOTAL with the engine running ~3000RPM and you take what you get at idle. ACVWs don't have a harmonic balancer, just a steel pulley, and the meaning of the notches on it varies depending upon what year engine it left the factory on. If there's a small dimple on the rear (rear is rear, that's toward the bumper) side of the pulley it's TDC. If in doubt, probe #1 or #3 piston with a soda straw while you rock the engine back & forth and you can feel where TDC is within a degree or two. Or remove the bolt and observe the position of the woodruff key - it'll be at 9:00 at TDC on #1 or #3.

It's quite hard for me to believe that ANY engine would be able to attain 110MPH breathing through a single 34PICT-3....100MPH, maybe - given enough road. You may want to check that speedometer for accuracy.

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Thank you for all the great info!  Here are a couple of added bits on this Engine ID thread. 
1) The unidentified engine does actually have a mechanical fuel pump so now I clearly see this engine is not the original (which we suspected anyway). But still no markings even in the locations entioned, and they don't look like they've been removed.  It just looks like they've never been there.  Very strange.
2) The speedometer does actually read between 105~110 MPH at top speed.  Although it does take a good piece of road to get there it's not as much as I would expect.  This bug gets there pretty quickly.  I'll bet as you mentioned the speedometer needs calibration.  I will do tire height measurements and gear ratio checks in the spring when I get the car out.
3) Last thing, does your advice on the timing apply to the Fuel Injected motor or an earlier model?  Because as we have now determined my engine has a mech pump so it's not a FI motor.
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Musturd wrote:
...does your advice on the timing apply to the Fuel Injected motor or an earlier model?  Because as we have now determined my engine has a mech pump so it's not a FI motor.

It applies to any motor equipped with the 0 231 178 009 distributor. Their curve varies a bit from one to the next so you can't trust that any particular initial setting is going to yield the same total advance, they must be set so as not to exceed the maximum safe advance under the worst-case condition when you accelerate hard at ~2500RPM where all of the advance is in - that's about 30-32°. The engine can actually tolerate about 10° more under high-speed/light-load conditions but a centrifugal advance distributor can't sense load so this compromise setting must be used (nobody has the self-control needed to always go light on the throttle below ~3500RPM).
The best distributor for you would be a 0 231 170 034 as used on 49-state 1974 4-speed cars; it has both a centrifugal and a vacuum advance mechanism so it can react to throttle position - set at 7.5°BTDC initial it'll yield around 42.5° at light cruise, which improves highway fuel economy and gives cooler running. It also is less likely to suffer from a hesitation on acceleration as is often present with an 009 on a dualport....but the 009 will work, no need to rush out and find a replacement if the car runs well enough.

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