Engine – Proper Deck Heights Blocks & Heads
Whenever you go through an engine or cylinder head re-build, there will be some amount of "re-surfacing" that has to be performed to either the block or the head. Most frequently, it's the cylinder head. This is also known as "decking."
For machining purposes, deck height on an engine block is the measured distance between the "Center Line of the Main Journal" to the "Deck Surface". This can only be performed with the engine block disassembled and the crankshaft removed.
Toyota Factory Heights / Specs:
- Early 20R Blocks 75-80 9.120"
- Early 22R Blocks 81-84 9.120"
- Late 22RE Blocks 85-95 8.930"
For easy identification purposes, with the engine still assembled, deck height on an engine block is the measured distance between the "Oil Pan Rail" (bottom of the engine block) to the "Deck Surface" (top of the engine block). Toyota 20R, 22R and 22RE engine blocks have these factory deck heights:
- Early 20R Blocks 75-80 11.280"
- Early 22R Blocks 81-84 11.280"
- Late 22RE Blocks 85-95 11.090"
Deck height on a cylinder head is the distance between the bottom of the "Camshaft Journal" to the "Surface of the Cylinder Head" itself. Toyota 20R, 22R and 22RE cylinder heads have these factory deck heights:
- Early 20r/22R Heads 75-84 3.290"
- Late 22R/22RE Heads 85-95 3.130"
These numbers are especially important if you have purchased a pre-owned engine and have no idea what, if any, modifications were made prior. In other words, it's a starting point in establishing how much re-surfacing has already been performed to the head or block. Example: If you have a late 22RE cylinder head that has a measured deck height of 3.110", then it is probably safe to say that the head has been "decked" approximately 0.020".
From stock deck height measurements, LC Engineering recommends for "street use", no more than 0.020" of re-surfacing or use a head shim to achieve proper deck height. Anytime you deck a head, block or both, by more than 0.010" you are affecting the camshaft timing with the engine resulting in a "Lazy" motor. If increased compression is the goal, or the surface requires "decking" because of minor warping, then an adjustable camshaft gear will be ideal.
If you wish to deviate from any of the factory specifications, "decking", larger camshafts, bigger valves, domed pistons, etc...please call the experts at LC Engineering to get the right answers to your questions before it costs you more. With over 20 years of proven experience, we can assist in completing the right engine components for your needs.
Measuring "Center Line of the Main Journal"
Measuring "Oil Pan Rail"