Scirocco Engine Swap - Audi 3A 2.0L 8V Block / JH Head
So, you're looking for more power?  As the old saying goes, "there's no replacement for displacement."

Here we are going to cover the basics of swapping the stock 1.8L 8V block (JH) for the 2.0L 8V block (3A) found in the 1988 to 1990 Audi 80 (possibly also 1991/1992) and some Audi 90's (years unknown).  This is a very straight forward engine swap that will be unnoticable in appearance to most people. Basically, you take a stripped 3A block and bolt all your stock parts to it.  Simple, eh?

Specifications for the stock Audi 3A motor:

Audi 3A / JH Swap

121.0 cu. in. (1983 cc)
3.25 in. (82.5 mm) bore
3.65 in. (92.8 mm) stroke
10.5:1 compression ratio
108 hp @ 5300 RPM
121 ft. lbs.@ 3200 RPM
Piston oil squirters

When planning this swap, several questions arose:
  1. What head do I use with the block?
  2. What head gasket do I use?
  3. What do I do about the breather assembly on the front of the block?
  4. What oil pan/pump do I use?
  5. What pulleys do I use?
  6. What clutch do I use?
  7. What exhaust manifold and downpipe do I use?
  8. What distributor do I use?
  9. Do I need a knock sensor since this has a higher compression ratio?

While answers varied, I was looking for the most straight forward swap.  This meant retaining as many stock parts as possible, maintaining stock appearance, using factory fuel injection, and being very reliable.

I also questioned myself about how far to take this project, and was left with two choices: (1) keep cost to a bare minimum without sacrificing reliability and enjoy a substantial power increase, and (2) ignore all common sense, drain the bank account and build an expensive turbo motor.  Since the motor only had 95,000 and was very clean, I chose to simply "drop it in" and feed the appetite for power, without going overboard.

This was an easy decision.  My head was recently refreshed and had a G-grind cam installed. I also wanted to keep the stock fuel injection.  The head was removed with the manifolds attached and set aside. If you haven't done any headwork, now is the time.  A valve job, valve seals, cam, and porting are all recommended.

It is possible to use the Audi 80 head, but for simplicity, stick with the stock JH head.

Head Gasket
Use the Audi 80 2.0L head gasket. 3aheadgaskets.jpg (22041 bytes)
Breather Assembly
The Audi breather assembly was removed, which left two holes to fill.  The round hole was easily filled using a freeze plug. The remaining hole was covered with a plate that was drilled and tapped to allow mounting of the warm up regulator in its factory location.



Blockoff kit available from GAK Motorsports

3abreather1s.jpg (18217 bytes)

3abreather2s.jpg (16610 bytes)

3abreather3s.jpg (16439 bytes)

Oil Pan/Oil Pump
Due to the fact the Audi 80 engine was mounted longitudally instead of transversely like the Scirocco, the Audi oil pan and pump must be removed and the original Scirocco parts used.  Also, the Audi oil pump was designed for a hydraulic head, and not the solid lifter head. 3apan1s.jpg (13019 bytes)
Audi 80 2.0L oil pump 3aoilpump3s.jpg (18804 bytes)
VW 1.8L oil pump

Note: If you buy a new oil pump, casting flaws in the oil pump housing may require filing to allow the oil pan to fit.
Click for picture of modified housing

3aoilpump1s.jpg (19973 bytes)
The timing belt sprockets (crankshaft and intermediate shaft) are the same as the Scirocco, so you do not need to change them unless they are damaged. You will need to use the Scirocco crankshaft pulley, and waterpump and pulley.

Audi pulley shown to right

3apulley1s.jpg (17416 bytes)
Scirocco pulley shown to right.

Tip: When removing socket head cap screws, a bit of valve grinding compound gives extra grip to help avoid stripping the head.

3apulley2s.jpg (17482 bytes)
Be sure to replace the seals while prepping the block. The rear main seal is especially important because oil leaks can damage the clutch. 3aseals.jpg (16893 bytes)
The stock VW 210mm clutch will work fine. Upgrades are available which should be considered especially if your clutch needs replaced. clutch1s.jpg (16850 bytes)
clutch2s.jpg (17398 bytes)
Exhaust Manifold/Downpipe
The 3a block is the same height as the JH block, so your original exhaust manifold and downpipe will work fine.
Distributor / Knock Sensor
You have two choices when considering what distributor to use: (1)  a modified Scirocco distributor or (2) an Audi 80 distributor with the addition of a factory knock sensor. 3adists.jpg (14286 bytes)
(1) A modified 1.8L Scirocco distributor:  This requires swapping the gear at the bottom to a 3A gear and the use of an adapter plate.  You CAN NOT use a knock sensor with this distributor.  You will need to use high octane gas and conservative timing to avoid engine damaging knock.

With high octane gas and conservative timing, this setup has been used successfully. Personally, I prefer option 2 below due to the added safety of the knock sensor. Option 2 will require additional effort and expense.

(2) An Audi 80 distributor with the addition of a factory knock sensor:  This distributor will drop straight in to the block with no modifications. You will need the rotor that is made for this distributor.   The factory wire connector will plug in and the engine will run, BUT without the addition of a knock sensor, you will have no timing advance (and a lot of missing power!). You MUST add a factory knock sensor when using this distributor. The knock sensor will control timing advance and retard when dangerous engine knock occurs.

Click here for Knock Sensor Installation information.

I felt using the 3A distributor would be most reliable and chose this route. The factory harness plugged directly into the distributor and the engine ran well with out a knock sensor (11 degrees advance and 93 octane gas).  BUT, there was a noticable lack of power and torque, especially at higher RPMs. Discussions revealed that this was due to the lack of any timing advance with this distributor.  The addition of a knock sensor became a necessity.

Fuel Mixture Adjustment
Just when you thought you were finished, there is one more important thing to do - adjust the fuel mixture.

Click here for CIS Fuel Mixture Adjustment information.

I quickly noticed that the engine was running hot - hot enough that I once turned on the heater in 95 F weather!  The oil temperature was running 125 to 130, with the water temperature gauge in the dash cluster nearly pegged.  After adjusting the fuel mixture, oil temperature dropped to 115 to 120 and the water temperature gauge needle resting just on top of the LED.

Miscellaneous Observations
  • The water pump housing is the same on the 3A and JH engine, but water pump and pulley are not the same.
  • The bracket next to intermediate shaft that the A/C compressor bracket attaches to is same on the 3A and JH blocks.
Tips aka "Leasons Learned"
  • Have two floor jacks to make engine removal and installation easier.
  • Do not drop block/tranny on your only floor jack at 1:00am!
  • Have duplicate tools - the one you need will always be under something or across the room.
  • Twist engine at an angle when dropping (passenger side forward)
  • Put the dust shield on BEFORE mounting the clutch pressure plate!
  • Buy lots of brake cleaner for cleaning.
  • Allow plenty of time to clean and paint parts.
  • Check firewall behind engine for heat damage/rust. PICTURE
  • When trying to reattach inner CV joints, make sure tranny is out of gear - the flanges turn much easier that way!
  • A cover rubbing a pulley sure makes a lot of noise!
  • Have lots of patience!
Cost Overview
Below is a list of costs incurred while doing this swap.  This meant simply as an example to help you plan your project. Your prices will vary. The oil pump and water pump were replaced because they had 200,000 miles on them. The fuel injector was replaced because the end pulled off during removal.



Audi 3A Engine - 95,000 miles


Blockoff kit for breather holes (GAK Motorsports)



Front Seals (Cam, Crank, Intermediate shaft)


Rear main seal


Head bolts (10)


Motor mount (passenger side)


Intermediate shaft oring


Oil cooler seal


Oil filter mount block gasket


Head Gasket


Oil Pump


Water pump


Distributor Rotor


Distributor Cap


Fuel injector orings ( four large ones)




Audi 3A distributor


Fuel Injector


3-way oil cooler hose




Fuel injector orings (three small ones - one on new injector)


Hose clamps (3)



Sales Tax



Labor to press in new passenger side engine mount



Misc expenses (brake cleaner, paint)


Misc expenses (brake cleaner, straps, torque wrench, wire ties)


Misc expenses (brake cleaner, oil, filter, paint)


Misc expenses (brake cleaner, hand cleaner, anti-freeze)



Total Expenses



Swap stock Scirocco JH 1.8L block for Audi 80 3A 2.0L
  • Use Audi 80 3A 2.0L block
  • Use stock JH head
  • Use Audi 80 3A 2.0L headgasket
  • Use stock exhuast manifold/downpipe.
  • Freeze plug needed to fill breather hole
  • Plate needed to fill breather hole
  • Use Audi 3A distributor and rotor
  • Use Scirocco oil pump
  • Use Scirocco oil pan
  • Use Scirocco waterpump/pulley
  • Use Scirocco crankshaft pulley
  • Use Scirocco clutch
  • Audi crank and intermediate shaft timing belt sprockets are the same as Scirocco
  • Add knock sensor setup

Specifications on the Audi 80 can be found in the AudiWorld Model Guide.

3ablocks.jpg (19102 bytes)


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