Storing Gaskets, Shims, Circlips and O-Rings During an Engine Rebuild
The small parts inside an engine are the ones most easily lost or damaged. Gaskets crease, o-rings pick up dirt, shims get mixed and circlips vanish into workshop floors. A cleaner, more careful approach to storage makes a rebuild safer and faster, and it reduces the chance of a leak or a failure after you have finished.
Keep gaskets flat, keep o-rings clean, keep shims in order and label every bag with the engine, the assembly and the position.
Gaskets: keep them flat and clean
Store gaskets flat in a bag large enough that they do not need folding. Creased paper or composite gaskets can leak. If you are keeping an old gasket as a pattern for a new one, label it clearly as old, pattern only so it is not reused by mistake. For gaskets larger than our biggest bag, store them flat in a labelled folder or box.
O-rings and seals: keep them clean and separate
Dirt on an o-ring can cause a leak later. Keep new o-rings in their own bag until the moment they are fitted, and keep old ones separately and labelled in case you need to match sizes. Do not stretch o-rings or store them under tension.
Circlips and retaining rings
These small parts are easy to lose and easy to confuse. Bag circlips in a small bag per assembly and label them with the shaft or bore they came from, because sizes are often only a fraction of a millimetre apart. Note whether each is an internal or external clip.
Shims and washers
Keep shims in order and record the thickness on the label if you have measured them. Never mix shims from different assemblies in one bag, because their order and thickness often set clearances.
Good sizes for engine parts
| Part | Suggested size |
|---|---|
| Circlips, small o-rings and shims | 30 x 30mm to 50 x 50mm |
| Small gaskets and seal sets | 80 x 120mm to 100 x 100mm |
| Gasket sets and larger seals | 125 x 125mm to 150 x 150mm |
| Longer flat gaskets | 200 x 100mm, if it fits |
Measure a flat gasket before choosing a bag, as many head and cover gaskets are longer than our largest bag. For those, store them flat in a labelled box or folder.
A simple routine
- Clean the part and let it dry before bagging.
- Bag it straight away, before it is put down on the bench.
- Label the bag with engine, assembly, position and quantity.
- Keep the bag with the assembly it came from.
- Check the bag before reassembly and replace anything that is damaged.
Common mistakes
- Folding gaskets to fit a bag that is too small
- Mixing shims from different assemblies
- Reusing old gaskets and o-rings that have set or cracked
- Leaving small parts loose on a workbench
Frequently asked questions
Should I reuse old gaskets?
In most cases, fit new ones. Keep the old one only as a pattern.
Can oil damage the bag?
A little oil is fine, but wipe parts first. Excess oil can make labels peel and bags slippery.
How do I store a very long gasket?
Lay it flat in a labelled folder or box, with a piece of card to support it.
How many bags should I buy?
Buy a pack of 100 in your two or three most-used sizes. You will use them more quickly than you expect.
Related guides
See our guides on fasteners for car restorations, motorcycle rebuilds and a complete parts storage system.
Browse our grip seal bags in 16 sizes, or use the size guide if you are not sure which to choose. Need larger quantities? See our wholesale grip seal bags.