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We’re Pulling Back The Curtain…

A Behind-The-Scenes Look At The EQ Cylinder Head Assembly Process

The new cylinder head casting is placed in V-Blocks for proper cleaning. Valve guides get brushed to insure they are clean.

All combustion chamber areas are air blown to ensure no debris is left from manufacturing of the casting.

Valve guide areas are inspected, and all oil and coolant passages are blown clear and free of debris.

EngineQuest follows Prosis Pro standards for all cylinder head assembly specifications.

Moving into the cylinder head assembly clean room, the team begins the process of checking all the specs. Working on one cylinder head casting and assembly part kit at a time may not be the fastest way to do this process; it does confirm that the EQ assembled cylinder head meets the quality you deserve in our products. Manufactured with the EQ Difference. Assembled in the USA.

Each valve stem is checked for O.D. From top to bottom to ensure specifications.

All specifications are documented.

Valve guide I.D. measuring gauge is inserted into each guide and I.D. is checked and verified.

If a valve guide I.D. does not meet the specifications, it is taken outside of the clean room, reamed to size, and finished with a flex hone.

After sizing has been verified, the cylinder head is recleaned to remove any debris from the reaming process.

Back in the cleanroom, all valve train parts are laid out for assembly. Keep in mind that the EQ team member is focused on only 1 cylinder head at a time.

All valves are cleaned with a non-lint cloth.

All valve stems receive a good coat of FL-128 assembly lube to prevent a valve-to-guide dry start.

All valve guide I.D.s receive a good coat of FL-128 assembly lube to prevent a valve-to-guide dry start.

Valves are inserted into valve guides of the cylinder head.

Valve head to valve seat concentricity is checked.

Valve stem seals are placed on each valve guide by hand.

A Valve Stem Seal installation tool is used to ensure proper seal installation.

Note that you can see the FL-128 Assembly lube on the top of the valve stem above the seal in the close-up image. Dry starts cause premature engine failure. EQ makes sure this does not happen.

Cylinder head casting is moved over to the valve spring bench. The valve spring and retainer is installed over the valve stem, seal, and guide area. Spring is then compressed.

The valve locks are inserted, and spring is un-compressed. Valve locks are checked to make sure of proper alignment.

One by one, the EQ team member moves the cylinder head through the process of setting the retainer and keepers onto the valves.

The look of a completed assembled EQ cylinder head. (On overhead cam cylinder heads, EngineQuest does not supply camshaft or rocker assembly).

Each cylinder goes through a vacuum check to ensure the valves are seated properly.

If the cylinder head does not pass the vacuum check, it is taken apart and issue is corrected.

An industry standard HEAT TAB is installed. A heat tab is used for monitoring engine temperature to determine if an engine has exceeded the recommended margin, otherwise known as “overheating.” Casting is stamped with team member’s steel stamp, which helps with traceability of the assembly, if a warranty issue should arise.

Each assembled casting is then placed into a poly bag to ensure cleanliness.

The poly bagged cylinder head is placed into a padded carton.

Packed carton is labeled. Lot traceability of each unit assembled is right on the label.

Assembled cylinders heads are ready for immediate delivery, and backed by our parts and labor warranty. Assembled in the USA with 100% new oe type stainless steel valves and parts.