FS: 928 16v Hybrid Engine

[ideola]

Project History
I acquired a 1980 euro-spec 928 back in Feb 2005, with the 4.5L motor. I have been driving it in bone stock form since that time. In mid 2005, I connected with David Lloyd, president of the 928 Owner's Club, and principle in Musante Motorsports out in CT. After much discussion about my plans for the 928, I began developing a high performance replacement motor (details below). In 2006 I went thru a divorce which pretty much killed all of my projects for a couple of years (I own four other water-cooled Porsches: a 924 NA, two 931s, and a 924S).

Two years later, my 931 ultra-wide-body race car project is finally moving again, and the other cars (including the Shark) are all road-worthy and well-sorted. However, the engine replacement project for the Shark is on the back burner for the foreseeable future. While I hate to let go of this motor, my goals and priorities have shifted since I first started down the path in 2005. The 928 runs just fine with its stock 4.5L, and I am at least a year or two a way from being able to tackle the replacement.

Details of the Motor
The short block is a 1985 5.0L acquired in 2005 from 928 International. The top end is a 1980 4.7L euro-spec acquired from a 924board.org member (Colin Jensen) in the Vancouver area, also in 2005. I had the short block and top end shipped to Musante Motorsports. David Lloyd helped me spec out the details. Musante subsequently reconditioned the block, fly cut the pistons for valve clearance, and performed a complete reconditioning of the heads. I have full receipts and documentation from Musante.

This is the exact same configuration that David is running in his track 928. In David's car, the CR is 11:1, which requires high octane + octane booster (or full blown race fuel), and produces in the neighborhood of 350 BHP. It essentially amounts to a 4.7L euro-spec stroker. The best part of this motor is that it is a direct bolt-in to an early chassis. There is no wiring harness conversion required, and the 5.0 block mounts directly into the early chassis. Easy-peasy. This is a complete, ready-to-build, fully-prepped motor, suitable for spirited street driving or a dedicated track car. The only things required to finish the motor are:
- seal & gasket kits for short-block and top-end
- typical tune up components (i.e. plugs, wires, filters, etc.)
- flywheel
- oil pan
- CIS

After consulting with Dave, I opted for the hybrid-stroker approach because it was less expensive and more bolt-in than any of the available supercharger alternatives for the 16v engines. In other words, the biggest bang for the buck without requiring a complete engine+CIS+wiring swap. I planned to re-use the existing CIS setup in my '80 4.5L, so there was no need to source a complete CIS setup. I was also planning to reuse the same flywheel. So for anyone with an early chassis, the only thing required would be the seal kits, tune-up parts, and an oil pan (last I checked, 928 International had pans listed for $100). The engine has been in storage in my climate-controlled garage since 2005, wrapped in plastic sitting in the same crate it was shipped to me in from Musante. It can be shipped since it's still in the original crate; however, it cost me nearly $700 to have it shipped from CT, so I would obviously prefer a local sale.

Ballpark Cost
I have invested ~$6K in acquiring the components and all of the prep work, not including the shipping. The exact figure can be provided and documented to serious inquiries. If anyone is interested, or knows of anyone who might be, please drop me an email (dan DOT beckett AT ideola DOT com) or call my cell phone: 734.679.1310. The crate is in my garage in Plymouth MI, so I can arrange for in-person viewing of the bits for serious inquiries.

[Danglerb]

How was the stroke changed?

What was done to the heads?

[ideola]

Technically, the stroke wasn't changed on the 5.0L short block.

The heads were completely reconditioned: tear down, inspect guides (Musante determined that the guides were sufficient and did not need replacing), three angle complete valve job, and the heads were milled to increase compression to 11.0:1

On the short block, it was disassembled, hot-tanked, mains were checked and determined that align-honing was not required, cylinders were finish honed, and the pistons had valve reliefs cut to accommodate the 4.7L heads noted above. In addition, the complete rotating assembly has been balanced.

As noted above, I have receipts from Musante documenting the work completed.

[ideola]

Bump. Asking $5K.

[Danglerb]

Did you need to change the pistons after honing (how was it honed?) to a larger size?

Is this a complete engine with all the intake and related Euro S injection parts?

PM as much of detail as you can so I can pass the info on to another person.

Thanks