Engine Reconditioning Process Explained

How is an Engine Reconditioned?

PROCESS EXPLAINED

Before any cylinder head reconditioning can occur, it's important to ensure the cylinder head itself is actually servicable. This is the determining factor on whether the cylinder head will actually work once it is repaired.

To do this, the cylinder head hardness is checked. A hardness tester (For example the Brinell tester) can work out whether a cylinder head is too soft or not. If it is too soft, it may need to be hardened again. Sometimes this is not possible and an entirely new cylinder head is required. 

Too soft is bad

A soft cylinder head will result in a blown head gasket quickly, so it's vital not to use one.

Straighten it out

Once the strength of the head is determined, the dimensions and condition of the head are examined. If the head is not straight, it will require straightening. If the bores are not round they may need to be bored, or maybe blasted. 

Crack testing is then undertaken to determine if the cylinder head has any cracks. This is done by both pressure testing and magnetic crack testing, which identifies any cracks. This is very important because any tiny and unseen cracks will lead to big issues later on. 

Valves & K-Lines

After straightening, boring, benching and pressure testing, valve guides and K-Lines are fitted. Camshaft tunnels are also line bored to ensure they are straight. Main bearing tunnels are also checked.

Once they are fitted, the cylinder head is near complete and is then surfaced to ensure it's flat. It's recommended the same is done to the block.

Quality Assurance

Prior to leaving the workshop, every cylinder head is checked at least once if not twice. It's usually the case that the mechanic that does the inspections does not do the actual work as the review needs to be independent. 

And you're done! Now you've got a reconditioned cylinder head ready for fitment.