Reconditioned cylinder heads
Cylinder head reconditioning in Sydney is one of the main jobs in our machine shop. The cylinder head sits on top of the engine block. It holds the valves, and on many engines the camshaft. When a head cracks, leaks or warps, the engine cannot seal properly.
Reconditioned cylinder heads: the process
- Strip and clean. The head is taken apart and every part is cleaned. The parts are kept in order.
- Test. The head is pressure tested, crack tested, or both. Pressure testing seals the water passages and pumps in air to find leaks. Crack testing finds cracks you cannot see. See crack testing.
- Measure. Both faces and the manifold faces are checked for straightness. The camshaft tunnels, water jackets, valves, valve guides and valve seats are checked too.
- Machine. Parts that are out of spec are machined or replaced. A warped face is resurfaced so it sits flat again. Valves can be refaced and valve seats machined.
- Assemble and test. The head is put back together and the clearances are set to the maker's figures.
Read the full reconditioned cylinder heads guide
What is cylinder head reconditioning?
It is a full service of the head, done in steps.
- Strip and clean. The head is taken apart and every part is cleaned. The parts are kept in order.
- Test. The head is pressure tested, crack tested, or both. Pressure testing seals the water passages and pumps in air to find leaks. Crack testing finds cracks you cannot see. See crack testing.
- Measure. Both faces and the manifold faces are checked for straightness. The camshaft tunnels, water jackets, valves, valve guides and valve seats are checked too.
- Machine. Parts that are out of spec are machined or replaced. A warped face is resurfaced so it sits flat again. Valves can be refaced and valve seats machined.
- Assemble and test. The head is put back together and the clearances are set to the maker's figures.
A head must be flat for the head gasket to seal. The surface finish matters too. Gasket makers say faces that are out of spec must be refinished.
When do you need it?
- After overheating. A head that has run hot should be checked for warping and cracks before it goes back on.
- A failed head gasket. Signs include white exhaust smoke and the engine running hot. The head should be checked before a new gasket goes on.
- A cracked head, or coolant loss with no outside leak.
- During a full rebuild. The head is reconditioned as part of engine reconditioning.
How we do it at Reco
The test method depends on the metal. Magnetic particle testing works on cast iron heads. It does not work on aluminium.
What it costs
The price depends on the head and how much work it needs.
Questions
Can a warped cylinder head be fixed?
Often, yes. A warped head can be machined flat again if it stays within the maker's limits. We measure it first and tell you what we find.
Should a head be tested before a new head gasket goes on?
Yes. A new gasket needs a flat, sound face to seal against. Testing and measuring the head first tells you if it can be reused.
What is a valve grind?
A valve grind is the valve part of a head job. The valve faces are refaced and the valve seats are machined, so each valve seals when it closes. The valve stem height is then checked. Worn valve guides are checked at the same time.
Related services
More answers are on our FAQs page. To get a head looked at, send an enquiry.
Who it is for
- After overheating. A head that has run hot should be checked for warping and cracks before it goes back on.
- A failed head gasket. Signs include white exhaust smoke and the engine running hot. The head should be checked before a new gasket goes on.
- A cracked head, or coolant loss with no outside leak.
- During a full rebuild. The head is reconditioned as part of engine reconditioning.
Price guide
The price depends on the head and how much work it needs.
Reconditioned cylinder heads FAQs
Can a warped cylinder head be fixed?
Often, yes. A warped head can be machined flat again if it stays within the maker's limits. We measure it first and tell you what we find.
Should a head be tested before a new head gasket goes on?
Yes. A new gasket needs a flat, sound face to seal against. Testing and measuring the head first tells you if it can be reused.
What is a valve grind?
A valve grind is the valve part of a head job. The valve faces are refaced and the valve seats are machined, so each valve seals when it closes. The valve stem height is then checked. Worn valve guides are checked at the same time.
Everything done under one roof
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