Audi S4 B6 B7 4.2L 40V BHF BBK Engine Rebuild Program

Regular price $11,999.95

The original and most trusted 4.2L 40V Chain Driven engine rebuild on the market. With nearly 100 successful rebuilds as of late 2023, we can confidently say we are a master at our craft! All of our rebuilds come with a final build sheet and many pictures of the process to keep for your records. 

All stage engine builds include a sleeved engine block due to out of roundness of factory bores. 

Customers must establish contact prior to shipping and purchase the desired engine rebuild stage in full before work begins. Shipping to or from our facility is not included. Local drop off and pick-up is available free of charge. Never shipped an engine? Let us help guide you through the process! We typically see shipping rates between $175-$500 one way within the continental United States. We do offer a 3% discount on all stage build options if customers desire to pay by check or bank-bank transfer options.

Long blocks are to be delivered to us without accessories. Accessories include: Oil Filter Housing, Water Pump & Pump Shaft, Power Steering Pump, A/C Compressor, Alternator & Bracket, Oil Cooler, Exhaust Manifolds, Engine Mounts, Knock Sensors, Intake Manifold, Coil Packs, and Cam Sensors. Spark plugs can be left in the engine, but rebuilds will not include spark plugs.

We offer a 24 month warranty for any of our stage engine builds not used with an aftermarket forced induction system. We cannot warranty engines on forced induction as there are too many issues that can arise from custom tuning which are out of our control. Please ensure you are using new fuel injectors on all engine rebuilds as we do not cover fuel injection related failures. Our warranty does not cover any labor or parts to install/remove the engine from the vehicle. All warranty work is only available at our facility. 

Engines must be shipped directly to our facility at the following address. Purchase and tracking needs to be completed and sent to AMTuned prior to engine arrival.


541 S Flagler Ave. Unit # A-West

Pompano Beach, FL 33060

AMTuned Engine STAGE 0 SLEEVED: Refreshed BHF / BBK 4.2L Long Block with 20k mile warranty on Stage 0 engine option only. TURN AROUND TIME IS ABOUT 8-12 WEEKS AFTER PASSED INSPECTION. 

  • Complete timing service utilizing the AMTuned ultimate timing kit.
  • Hydraulic roller rocket tappets are fully disassembled to free seized tappets, cleaned, and reassembled.  
  • Cylinder head refresh including cleaning and inspection. Replacement items include new guides, upgraded valve guide seals, and gaskets. Cylinder head mating surface will be skimmed to ensure optimal sealing during install. Valve seats will be cut, and assembled heads are pressure tested. 
  • Engine block refresh including cleaning & cylinder bore sleeving. Replacement items include main bearings, connecting rod bearings, piston rings, lower engine o-rings, valley pan gasket, valley pan check valves and cylinder head gaskets. 
  • Engine is a fully assembled, timed, and sealed long block. 


AMTuned Engine STAGE 1 SLEEVED: Rated for up to 600whp & 7200 rpm. Turn around time is about 5 - 6 weeks. Turn around time is about 8-12 weeks after inspection. All items in Stage 0 Sleeved package with the addition of:

  • AMTuned 4340 forged H-Beam with tapered end connecting rod package.
  • AMTuned HD Valve Spring Package


AMTuned Engine STAGE 2 SLEEVED: Rated for 1000+whp & 8000rpm. Turn around time is about 10-14 weeks. All items in Stage 0 package with the addition of:

  • Sleeved engine block
  • Balanced rotating assembly
  • AMTuned design JE Pistons w/93 series pins
  • AMTuned 4340 Saenz Performance Connecting Rods
  • Supertech 1mm Oversize Upgraded Valves
  • Supertech valve spring kit with titanium retainers.
  • ARP 2000 head Bolts

We are the only company in the world utilizing our proprietary block prep service. This in-house developed process allows us to run a factory bore size and not cheat by using a smaller OD sleeve and a tiny piston. This results in engines that are more powerful with factory displacement over the competition. Our service removes the risk of the vapor ports between the bores cracking behind the sleeves and leaking coolant down into the crankcase. Below is a picture of a block that did not have our block prep service. We removed the sleeves to find cracked coolant passages between the bores and visible signs of coolant entering the crankcase.