From 1975 to 1982 Toyota produced the 20R & 22R four-cylinder engines that utilized a dual timing chain system. It proved to be very dependable and included steel timing chain guides. Then in 1983, Toyota decided to install the single row chain with plastic guides on all of their 22R engines. The single row timing chain is prone to stretching beyond the tensioner's limits, resulting in a loose chain. As the chain stretches, several things can occur. You experience improper camshaft timing, the plastic guides eventually break, the timing chain can either wear a hole in the timing cover or break entirely sending the pistons and valves to meet their fate. Not a pretty picture. LCE does supply a very heavy-duty single row chain with metal guides to give a little more life expectancy.
From 1985 to 1995, Toyota was still producing the single row timing chain for the 22R series engine, but made the deck height of the block and cylinder head shorter. This changed the centerline distance between the crankshaft and camshaft resulting in a shorter chain. Toyota recommends that you replace the single row chain every 70 to 80k miles.
As the evolution of our performance engines took place, LCE was experiencing problems with the single row timing chain. So, in 1995 we designed and started to manufacture the Dual Row Timing Chain Conversion Kit for the late 22R series engines. What a positive impact this made on the quality and performance of our engine packages. This kit is also available for those who want to convert their 85-95-22R series engine over to the dual row chain. LCE has spent countless hours on our engine dyno machine developing the proven quality products that we have provided our customers for the past 20+ years.