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01204 302 809
Mon–Thu 07:15–17:45, option 1 for engines

The rebuild process

Each stage of the work is documented to create a 12-page internal record. This is the sequence an engine follows from arrival to handover, and why the price is agreed part-way through rather than at the start.

The engine room bench with a strip-down laid out on a mat: timing chains, sprockets, bolts and gaskets, with tool chests behind.
The engine room bench during a strip-down.

  1. Cosmetic check and first assessment

    After an initial cosmetic check of the car we carry out a first assessment to satisfy ourselves that there is an internal engine fault and that a rebuild is necessary. Over the years several cars have arrived for rebuilds where we found early on that the fault lay elsewhere, saving the customer considerable unnecessary expense. The assessment may include oil analysis, cylinder bore imaging, DME analysis and a combustion gas test.

    A technician under a Porsche on a lift, studying a borescope screen, with the Hartech name painted on the workshop wall behind.
    Bore inspection by borescope, before anything is stripped.

  2. Engine and gearbox out

    Once satisfied, we remove the engine and gearbox as one unit, then remove the ancillaries, which are stored on pallets in our internal storage facility.

    An engine and gearbox removed from the car and sitting on a trolley.
    Engine and gearbox out as one unit.

  3. Strip and assess

    The long motor is transferred to the engine team, who strip and fully assess it. One stripped engine takes up two bays of racking; the strip-down room can hold seven.

    One engine fully stripped and laid out across two bays of steel racking, every component labelled.
    One engine, stripped, takes two bays of racking.

  4. Essential repair and options

    An internal meeting establishes the essential repair: the minimum work needed to return the engine to a serviceable condition, covering the initial fault and anything needing imminent attention. We then look at the other weak spots and identify optional work to strengthen the engine, typically a new intermediate shaft bearing, cylinder strengthening, new crank bearings, timing chains, cylinder head overhauls and pistons, and anything easier to address with the engine out that will reduce long-term running costs.

    A crankshaft on a blue stand on the engine room bench with its bearing shells laid out beside it.
    Crankshaft and bearings laid out for measuring.

  5. Pricing and the conversation

    We price the options on a spreadsheet and speak to you about what we have found and how to proceed. We can explain the engine at whatever technical level suits you, so that owners with no mechanical knowledge can still make an informed decision for their budget and plans for the car.

    Connecting-rod bearing caps arranged in two neat rows on the bench.
    Rod caps kept in order.

  6. Cleaning and machining

    Components go through three separate cleaning processes, including water blasting, and any necessary reworking in our precision in-house machine shop: four mills including 3-axis CNC, two lathes, a diamond skimmer and a diamond multi-axis honing machine.

    The in-house machine shop with mills and a lathe.
    The machine shop: four mills including 3-axis CNC, two lathes, diamond skimmer and multi-axis honing machine.

  7. Assembly in the clean room

    The engine is reassembled in one of two plastic-lined clean rooms, deliberately away from the main workshop and engineering areas to avoid the dirt, metal cuttings, noise and distraction of a typical workshop.

    Crankcase half on an engine stand with a new head gasket laid on, the workshop lights out of focus behind.
    Head gasket on, ready for the cylinder head.

  8. Refit and test

    The assembled long motor goes back to the workshop, where the ancillaries are checked and refitted and the engine and gearbox assembly is fitted to the car. Once running, a thorough test programme follows with at least five test drives and subsequent checks. Each stage of the work is documented to create a 12-page internal record.

    A complete M96 engine with intake manifold, alternator and exhaust headers, on a red engine stand in the workshop.
    A rebuilt engine ready to go back into the car.

After the rebuild

The oil filter is changed after the first 50 to 100 miles; for cars we fit the engine to, that is done before you collect. A running-in period of around 100 hours, typically 2,000 to 3,000 miles, follows, and we will talk you through it. Once complete, the engine moves to Millers Nanodrive CFS 10w50 NT+ oil.

Parts and labour are guaranteed for 24 months or 24,000 miles. The full terms set out what is covered and the running-in guidance.

Many rebuild customers then join the Lifetime Maintenance Plan, which spreads future servicing, the annual MOT and most repair labour into a monthly payment.

A wooden shipping crate strapped to a pallet in the workshop, stencilled Do Not Stack.
An engine crated for shipping.
A Porsche airbox in the workshop with a Hartech 4.1 plaque fitted.
A 4.1 conversion, badged.

Start with an assessment

Ring or write with what the car is doing. If it sounds like an internal fault we book a first assessment, and nothing is stripped until that confirms it.

01204 302 809
Option 1 for engines, option 2 for servicing and the workshop

Open
Mon–Thu 07:15–17:45
Closed
Fri, Sat, Sun, bank holidays
Drop-off
Before 17:00; locking up starts 16:45
Address
Firwood Industrial Estate, Off Thicketford Road, Bolton BL2 3TR

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Symptoms, noises, any diagnosis you have already had, and mileage if you know it.

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Preview build: this form is not connected to Hartech yet, so nothing is sent. Ring 01204 302 809 instead.