Piston & Ring Replacement
Also called engine rings change
Piston rings seal the combustion chamber and scrape oil off the cylinder wall. When they wear or stick, the engine burns oil, smokes blue, loses compression and pressurises the crankcase. Replacing rings means removing the head and sump and taking the pistons out, so the bores are measured at the same time. If the bores are worn oval or tapered, rings alone will not seal and the block needs boring with oversize pistons, which we quote once measured.
Signs you need this
- Blue smoke from the exhaust, especially under acceleration
- Engine oil level dropping steadily with no external leak
- Low compression that improves when oil is added to the cylinder
- Fumes or pressure pushing out of the oil filler when the engine runs
- Loss of power and rough running with oily spark plugs
Not all of these have to be present, and one of them on its own can mean something else entirely. That is what the diagnosis is for.
What the job includes
- Compression and leakage testing recorded before the engine is opened
- Bore measurement for wear, taper and ovality before rings are ordered
- New rings, gapped correctly in each bore
- Bore glaze removed or honed so the new rings can bed in
- New gaskets, seals and big end bearings inspected while access allows
- Running-in instructions and an early oil change after rebuild
How we do it
Confirm with a wet test
Adding a little oil to a low cylinder and retesting shows whether the loss is past the rings or past the valves.
Open and measure
The head and sump come off, pistons are removed, and the bores are measured to see whether rings alone will seal.
Quote the real scope
If boring and oversize pistons are needed we tell you before ordering, rather than fitting rings that will not last.
Hone, ring and rebuild
Bores are honed to hold oil, ring gaps are set in each bore, and the engine is rebuilt with new gaskets and seals.
Bed in and recheck
The engine is run in as specified, then oil is changed early and compression rechecked to confirm the rings have seated.
How we work
The same on every job, which is why we can write it down.
Diagnosis before quote
We find the fault first. A price given over the phone for a noise nobody has heard is a guess.
The price is agreed first
You approve the work and the cost before a spanner is picked up. Extra work means another call.
Parts you can check
We tell you whether a part is genuine, OEM, aftermarket or used, and what each one costs.
Old parts returned
Ask and we will hand back whatever we replaced. It is the simplest proof that the job was done.
Book piston & ring replacement
Fill this in and a person will call you back to confirm the time and the price. Only your name and one way to reach you are required.
You send this
Takes a minute. No payment, no obligation.
We call you
To confirm the car, the time and the location.
Tell us the car and the symptom
We will arrange a mechanic at your location, or a slot at the nearest workshop. No payment until the price is agreed.