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The M28 series engines in the Porsche 928 are good engines that can produce a lot of power when built properly.  In addition to this, the M28 engine can offer an exceptionally long service life if well cared for.  The issue with timing belt and water pump failures is due to lack of maintenance and as unfortunate as it is, many $5,000.00 928s are $7,000.00 away from being brought to a state of being well kept.  The more the cars change hands, the worse this problem seems to be getting.

For a long time, there was much doubt about the power potential of the M28 engine, but with the recent advancements in forced induction technology for the 928, power levels exceeding 650 HP are easily possible.  Turbocharging is the clear winner in this regard and while the M28 was not designed to be turbocharged, it does take to manifold pressure very well.

To get the absolute most out of a M28 series engine, we have developed a tried and true method that allows full restoration of the cylinder walls, while also allowing lowering of the compression by using new pistons.  Our method has proven durable over the long haul.

As a result of this, we offer a M28 shortblock rebuilding service which consists of the following:

  • Nikasil plated and diamond honed engine block finish honed to match new pistons
  • New forged pistons in 2618 or 4032 alloy, with compression ratio set to your specifications
  • Re-balanced rotating assembly to within 1 gram
  • New OEM main and rod bearings
  • New seals and gaskets

Upon completion, these rebuilds make the engine block new in appearance and you get a cylinder wall surface that is as tough as nails and allows you to run any piston material you desire.  For the 16V engines headed to be pressure fed, we recommend an 8:1 compression ratio, and for the 32V engines we recommend 8.5:1 compression ratio.  These values, coupled with a strong piston are the pathway to yield great power results while keeping the engine safe for moderately high manifold pressure values.

The protocol is simple, just send us your short block and specifications and we will return your block, fully rebuilt and ready for all other components to be bolted on.  As always, special projects are always welcomed and are quoted on a case by case basis.