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| Measuring "Center Line of the
Main Journal" |
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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 would be:
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Measuring "Oil
Pan Rail" |
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- Early 20R
Blocks 75-80 9.120"
- Early 22R
Blocks 81-84 9.120"
- Late 22RE Blocks 85-95 8.930"
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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"
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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 (Part# P8807) 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 (Part# 19-1052 single row
or Part# 19-1055 double row) 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 16 years of proven
experience, we can assist in completing the right engine components for
your needs. |
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