Thursday, April 14, 2011

Now For Something Completely Different

No bodywork yesterday evening. Engine work for a change. I’d told Gary (local Corvair guru) that I’d be by Saturday to return his ring groove scrapers he’d loaned me a month or so ago. That meant I actually had to use them on the assortment of pistons I have lying around. I started with the six that came out of Ringo’s former engine (an assumed 1964 110HP). It took a bit to figure out the most effective way to use the tool, but I was finally able to get the knack without breaking anything. The next six out of the Old Betty’s ’66 vintage 95 HP went much easier. I then went looking for the six pistons that were in the York engine (if I remember correctly, the code indicated a 110 HP LM engine). While digging through the shelves of parts, I discovered the box with that engine’s cylinders. Just for kicks, I pulled it off the shelf, removed a cylinder, and gave the bore a quick look. What? No ridge? I took the entire box over to the workbench and began measuring and inspecting to see if these could be the elusive set of cylinders that could be re-used with only a light hone. First, using a bore gauge, I determined the bore diameter of one of the set measured right around Chevy’s desired 3.4375”. Next, I inserted a saved compression ring into the bore at the same location I’d just measured. After making sure it sat level in the bore, I used feeler gages to measure the gap between the ends of the ring. I could get .060” to slide in, but not .062”. I slid the ring down to roughly the center point of the stroke in the cylinder and got the same gap measurement. The gap measured the same at the lowest point of the stroke. No taper. This was awesome, but I was skeptical that it would hold true for all the cylinders. Fifteen identical gap measurements later, I was convinced these cylinders had seen very little miles. While finding or trading for a running engine will probably still be the least expensive approach to getting Ringo his replacement engine, I now have the hard parts necessary for a fairly affordable fallback rebuild of the 95 HP engine.

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