Peugeot 504 Coupé in front of a greenhouse

Projects

Engines. Stories. Projects.

Particular attention to detail, to meet the specific needs of each project, whether it comes from a private owner or a professional. Three of them, told in the order in which we work: what arrived, what had to be decided, and what came of it.

Private owners & professionals Measured, checked, documented

Project 01

Peugeot 504 Coupé XN2 — engine rebuild and preparation

Vehicle Peugeot 504 Coupé

Engine2.0 L XN2 injection

Use Road, long journeys

Scope Top and bottom end

Client Private owner

The engine at final assembly

On arrival

The engine arrived seized, with a valve stuck in its guide after several years standing still. When an engine sits for a long time, the lack of oil circulation and the moisture can encourage corrosion in the guides, on the valve seating faces or in the bores. That kind of condition cannot be judged from the outside: it had to be opened, checked and measured before the work could be defined.

The brief

The owner wanted to use the car for long journeys. That use set the level of intervention. An engine expected to cover several hundred kilometres regularly has to keep clearances, lubrication and thermal stability suited to that use. Simply getting it running again would not have met the reliability sought.

Work carried out

We therefore chose a full overhaul of the top and bottom end, together with the fitting of electronic ignition. Up top, the guides were replaced and the seats then recut with reference to the new guides. The valves and their seating faces were checked to validate the quality of contact and the sealing. Down below, the bores were measured at several heights and on different axes before being brought back to the appropriate size. The rotating assembly was checked, then assembled with the functional clearances measured at every stage. Electronic ignition removes the wear associated with mechanical contacts and keeps a stable, repeatable advance curve, while preserving the outward appearance of the engine. All the main dimensions, recorded before the work and achieved after machining, were written down and handed to the owner. They will serve as the reference for the next overhaul, perhaps twenty years from now.

Project 02

Porsche 911 — cylinder head overhaul

Cylinder head Naturally aspirated and turbo

Scope Partial overhaul

Parts New guides and valves

Client Professional

Cylinder head set after seat regrinding — Porsche 911

Set of heads after the seats were reground

Approach

Full overhaul of the heads after checking the components and identifying the parts to replace. Guides, valves and seats are examined and measured before the necessary operations are defined, because wear can vary noticeably from one head to another. On turbocharged engines, the exhaust area receives particular attention because of the temperatures it is subjected to.

What was kept

Some seats could be kept where their condition and the scope for recutting allowed. Replacement is not automatic: when an original seat remains technically usable, keeping it avoids a further operation on the head. When it is too worn, damaged or no longer able to give a compliant seating face, it is replaced.

Work carried out

The heads are assembled with a new set of guides and new valves. The order matters: guides first, then the seats, recut concentric to the new guides and to the angle of the valves that will sit on them. Each valve is finally lapped onto its seat to check the actual contact, face by face. Depending on the customer's needs, this kind of work can also come with a dimensional survey or an inspection report.

Project 03

Renault 8 Gordini — cracked cylinder head repair

Vehicle René Bonnet Djet coupé

Head R8 Gordini

Subject Casting crack

Scope Full overhaul

Client Team

The cylinder head after fitting new guides — Renault 8 Gordini

The cylinder head after the new guides were fitted

Problem

This head, although new, carried a casting crack. A new part is not always free of defects: a discontinuity in the material can stay invisible before revealing itself under the first thermal cycles. On an R8 Gordini head, replacing it meant going back to search for a part that has become rare, with no guarantee of finding one in better condition.

Repair

We chose to repair the head by welding rather than replace it. The crack was first opened out until sound material was reached, so as not to simply close the defect at the surface. The part was then prepared, preheated, welded and cooled under control to limit residual stresses. This is where mastering welding and machining in the same workshop makes all the difference: after the repair, the geometry of the part is checked and the surfaces that need it can be brought back to size.

Work carried out

The head then received its valve guides and seats. After checking and restoring flatness, the guides were fitted and the seats machined with reference to their new axis, to recover concentricity and the quality of the seating face. The head then went back to its engine, and the car back on the road, which remains the best way to conclude this repair.

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