1991 RS 305

Just a "heads-up" about 1.6 rockers and pushrod clearence. Last fall, I posted that I loved the Comp 1.6's I'd installed, just prior to putting my IROC in storage. The 305 TPI seemed to pick up some grunt and ran strong. I thought all was fine.

Recently, when taken out of storage , I decided to re-set the valves to get rid of some ticking I'd "thought" I'd eliminated. I found I could not get a few of the valves to set quietly . I swapped other quiet roller tips to the problematic valves to see if it was possibly a few defective rockers, with no improvement. Then I tried the factory rocker in the noisey locations............they were silent. I also noticed, in a side-by-side comparison, that the pushrods were riding pretty low in the pushrod slots with the 1.6's, while they were centered in the pushrod slots with the factory 1.5's! For quiet operation and peace of mind, I changed them all back to the factory rockers!

Morale of the story, unless your absolutely sure the pushrod slot is long enough to allow clearance through full motion of the pushrod with the 1.6's , don't risk it. I "THOUGHT" mine, while now riding lower in the slot than before, were fine. Now I see they were not on some of the valves, and were not allowing me to set them properly. The "tick-tick" would come and go, but it was there. Fortunately, it was driven few miles this way, so nothing damaged. BTW, also changed my oil to remove any wear metals just to be safe!